Neighbors for Smart Rail v. Exposition Metro Line Construction Authority , 160 Cal. Rptr. 3d 1 ( 2013 )


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  • Filed 8/5/13
    IN THE SUPREME COURT OF CALIFORNIA
    NEIGHBORS FOR SMART RAIL,              )
    )
    Plaintiff and Appellant,    )
    )                           S202828
    v.                          )
    )                    Ct.App. 2/8 B232655
    EXPOSITION METRO LINE                  )
    CONSTRUCTION AUTHORITY et al.,         )
    )                    Los Angeles County
    Defendants and Respondents; )                  Super. Ct. No. BS125233
    )
    LOS ANGELES COUNTY                     )
    METROPOLITAN TRANSPORTATION )
    AUTHORITY et al.,                      )
    )
    Real Parties in Interest.   )
    ____________________________________)
    This case presents a challenge under the California Environmental Quality
    Act (CEQA; Pub. Resources Code, § 21000 et seq.)1 to the approval by defendant
    Exposition Metro Line Construction Authority (Expo Authority) of a project to
    construct a light-rail line running from Culver City to Santa Monica. Once
    completed, the transit line is to be operated by real party in interest Los Angeles
    County Metropolitan Transportation Authority (MTA).
    1      All statutory references are to the Public Resources Code unless otherwise
    specified.
    1
    Plaintiff Neighbors for Smart Rail (Neighbors) contends the Expo
    Authority‟s environmental impact report (the EIR) for the project is deficient in
    two respects: (1) by exclusively employing an analytic baseline of conditions in
    the year 2030 to assess likely impacts on traffic congestion and air quality, the EIR
    fails to disclose the effects the project will have on existing environmental
    conditions in the project area; and (2) the EIR fails to incorporate mandatory and
    enforceable mitigation measures for potentially significant spillover parking
    effects in the neighborhoods of certain planned rail stations.
    We agree with Neighbors on its first claim, but not on its second. (1) While
    an agency has the discretion under some circumstances to omit environmental
    analysis of impacts on existing conditions and instead use only a baseline of
    projected future conditions, existing conditions “will normally constitute the
    baseline physical conditions by which a lead agency determines whether an impact
    is significant.” (Cal. Code Regs., tit. 14, § 15125, subd. (a).) A departure from
    this norm can be justified by substantial evidence that an analysis based on
    existing conditions would tend to be misleading or without informational value to
    EIR users. Here, however, the Expo Authority fails to demonstrate the existence
    of such evidence in the administrative record. (2) The EIR‟s mitigation measure
    for spillover parking effects satisfied CEQA‟s requirements by including
    enforceable mandates for actions by MTA and the Expo Authority, as well as
    planned actions to be implemented by the municipalities responsible for parking
    regulations on streets near the planned rail stations. (§ 21081, subd. (a); Cal. Code
    Regs., tit. 14, § 15091.)
    Although we conclude the EIR fails to satisfy CEQA‟s requirements in the
    first respect claimed, we also conclude the agency‟s abuse of discretion was
    nonprejudicial. Under the particular facts of this case, the agency‟s examination
    of certain environmental impacts only on projected year 2030 conditions, and not
    2
    on existing environmental conditions, did not deprive the agency or the public of
    substantial relevant information on those impacts. (Environmental Protection
    Information Center v. California Dept. of Forestry & Fire Protection (2008) 
    44 Cal.4th 459
    , 485-486.) We will therefore affirm the judgment of the Court of
    Appeal, which affirmed the superior court‟s denial of Neighbors‟s petition for writ
    of mandate.
    FACTUAL AND PROCEDURAL BACKGROUND
    Formally known as phase 2 of the Exposition Corridor Transit Project
    (Expo Phase 2), the project at issue consists of a light-rail transit line running from
    a station in Culver City (the western terminus of phase 1, which connects to
    downtown Los Angeles), through the Westside area of the City of Los Angeles, to
    a terminus in Santa Monica. The project‟s purpose is to provide high-capacity
    transit service between the Westside area of Los Angeles and Santa Monica,
    thereby accommodating population and employment growth in the area,
    improving mobility for the large population of transit-dependent Westside
    residents, providing an alternative to the area‟s congested roadways, and
    enhancing access to downtown Los Angeles, Culver City, Santa Monica, and other
    destinations in the corridor.
    The Expo Authority issued a notice of preparation of an EIR for Expo
    Phase 2 in February 2007, circulated a draft EIR for public comment in January
    2009, and published its final EIR in December 2009. In February 2010, it certified
    the EIR‟s compliance with CEQA, selected the transit mode and route
    recommended in the EIR, and approved the Expo Phase 2 project.
    Neighbors petitioned the superior court for a writ of mandate, alleging the
    Expo Authority‟s approval of Expo Phase 2 violated CEQA in several respects.
    The superior court denied the petition in full, and the Court of Appeal affirmed,
    rejecting all of Neighbors‟s CEQA claims on the merits. We granted Neighbors‟s
    3
    petition for review, which raised only two issues: the propriety of the Expo
    Authority‟s exclusive use of a future conditions baseline for assessment of the
    project impacts on traffic and air quality, and the adequacy of the mitigation
    measure the Expo Authority adopted for possible impacts on street parking near
    planned transit stations. We resolve those two issues below.
    DISCUSSION
    I. Use of Future Conditions as a Baseline for Analysis of Project
    Impacts2
    The fundamental goal of an EIR is to inform decision makers and the
    public of any significant adverse effects a project is likely to have on the physical
    environment. (§ 21061; Vineyard Area Citizens for Responsible Growth, Inc. v.
    City of Rancho Cordova (2007) 
    40 Cal.4th 412
    , 428.) To make such an
    assessment, an EIR must delineate environmental conditions prevailing absent the
    project, defining a “baseline” against which predicted effects can be described and
    quantified. (Communities for a Better Environment v. South Coast Air Quality
    Management Dist. (2010) 
    48 Cal.4th 310
    , 315 (Communities for a Better
    Environment).) The question posed here is whether that baseline may consist
    solely of conditions projected to exist absent the project at a date in the distant
    future or whether the EIR must include an analysis of the project‟s significant
    impacts on measured conditions existing at the time the environmental analysis is
    performed.
    The Expo Authority‟s chosen analytic method and its stated reasons for that
    choice will be described in detail below; suffice it here to say the agency first
    2      With the exception of part II.B.5., post, which addresses prejudice, the
    analysis in this part (as well as that in pt. II., post) expresses the view of a majority
    of the court. (See conc. & dis. opn. of Liu, J., post, at pp. 1-3, 5.)
    4
    projected the traffic and air quality conditions that would exist in the project area
    in the year 2030, then estimated the effect that operation of the Expo Phase 2
    transit line would have on those conditions at that future time. With regard to
    traffic delays due to the rail line crossing streets at grade, the EIR found some
    adverse effects were likely in 2030, but none rising to a level deemed significant.
    With regard to air quality, no adverse effects were projected to occur; the project
    was expected to have a generally beneficial impact on air quality by slightly
    reducing automobile travel in the study area in comparison with conditions
    otherwise expected in 2030.
    Neighbors contends the Expo Authority proceeded contrary to CEQA‟s
    commands, thus abusing its discretion as a matter of law (§ 21168.5), in its choice
    of a baseline for analysis of traffic and air quality impacts. The Expo Authority
    and the MTA contend agencies have discretion to choose future conditions
    baselines if their choice is supported by substantial evidence, as the Expo
    Authority‟s choice assertedly was here.3 We first ask whether an agency‟s
    discretion ever extends to use of a future conditions baseline to the exclusion of
    one reflecting conditions at the time of the environmental analysis. Concluding
    that existing conditions is the normal baseline under CEQA, but that factual
    circumstances can justify an agency departing from that norm when necessary to
    prevent misinforming or misleading the public and decision makers, we then ask
    3       The Expo Authority also contends Neighbors failed to exhaust the future
    conditions baseline issue in the administrative forum. The Court of Appeal held
    the issue exhausted, and the Expo Authority did not raise the exhaustion issue in
    its answer to Neighbors‟s petition for review. As the exhaustion question was not
    raised in the petition for review or answer, and is not fairly included in the merits
    of the baseline issue on which we granted review, we decline to address it here.
    (See Cal. Rules of Court, rule 8.520(b)(3).)
    5
    whether the administrative record here contains substantial evidence of such
    circumstances.
    A. Use of Future Conditions Baselines Generally
    For the proposition that the baseline for an EIR‟s significant impacts
    analysis must reflect existing conditions, Neighbors relies heavily on section
    15125, subdivision (a) of the CEQA Guidelines,4 which provides: “An EIR must
    include a description of the physical environmental conditions in the vicinity of
    the project, as they exist at the time the notice of preparation is published, or if no
    notice of preparation is published, at the time environmental analysis is
    commenced, from both a local and regional perspective. This environmental
    setting will normally constitute the baseline physical conditions by which a lead
    agency determines whether an impact is significant.” (Cal. Code Regs., tit. 14,
    § 15125, subd. (a) (Guidelines section 15125(a)), italics added.)
    In Communities for a Better Environment, we relied on Guidelines section
    15125(a) and CEQA case law for the principle that the baseline for an agency‟s
    primary environmental analysis under CEQA must ordinarily be the actually
    existing physical conditions rather than hypothetical conditions that could have
    existed under applicable permits or regulations. (Communities for a Better
    4       The CEQA Guidelines, promulgated by the state‟s Natural Resources
    Agency, are authorized by section 21083 and found in title 14 of the California
    Code of Regulations, section 15000 et seq. By statutory mandate, the Guidelines
    provide “criteria for public agencies to follow in determining whether or not a
    proposed project may have a „significant effect on the environment.‟ ” (§ 21083,
    subd. (b).) In interpreting CEQA, we accord the Guidelines great weight except
    where they are clearly unauthorized or erroneous. (Communities for a Better
    Environment, 
    supra,
     48 Cal.4th at p. 319, fn. 4; Vineyard Area Citizens for
    Responsible Growth, Inc. v. City of Rancho Cordova, 
    supra,
     40 Cal.4th at p. 428,
    fn. 5.)
    6
    Environment, 
    supra,
     48 Cal.4th at pp. 320-322.) Applying this principle, we held
    the air pollution effects of a project to expand a petroleum refinery were to be
    measured against the existing emission levels rather than against the levels that
    would have existed had all the refinery‟s boilers operated simultaneously at their
    maximum permitted capacities. (Id. at pp. 322-327.)
    In a separate part of the Communities for a Better Environment analysis, we
    addressed the problem of defining an existing conditions baseline in circumstances
    where the existing conditions themselves change or fluctuate over time, as the
    refinery‟s operations and emissions assertedly did. (Communities for a Better
    Environment, supra, 48 Cal.4th at pp. 327-328.) We concluded that despite the
    CEQA Guidelines‟ reference to “the time the notice of preparation is published, or
    if no notice of preparation is published, . . . the time environmental analysis is
    commenced” (Guidelines, § 15125(a)), “[n]either CEQA nor the CEQA
    Guidelines mandates a uniform, inflexible rule for determination of the existing
    conditions baseline. Rather, an agency enjoys the discretion to decide, in the first
    instance, exactly how the existing physical conditions without the project can most
    realistically be measured, subject to review, as with all CEQA factual
    determinations, for support by substantial evidence.” (Communities for a Better
    Environment, at p. 328.)
    Communities for a Better Environment provides guidance here in its
    insistence that CEQA analysis employ a realistic baseline that will give the public
    and decision makers the most accurate picture practically possible of the project‟s
    likely impacts. (Communities for a Better Environment, 
    supra,
     48 Cal.4th at
    pp. 322, 325, 328.) It did not, however, decide either the propriety of using solely
    a future conditions baseline or the standard of review by which such a choice is to
    be judged. Our holding that the analysis must measure impacts against actually
    existing conditions was in contrast to the use of hypothetical permitted conditions,
    7
    not projected future conditions. And our holding that agencies enjoy discretion to
    choose a suitable baseline, subject to review for substantial evidence, related to the
    choice of a measurement technique for existing conditions, not to the choice
    between an existing conditions baseline and one employing solely conditions
    projected to prevail in the distant future.
    Justice Baxter therefore errs in citing Communities for a Better
    Environment for the proposition that an agency‟s future baseline choice is valid if
    it is “a realistic measure of the physical conditions without the proposed
    project . . . .” (Conc. & dis. opn. of Baxter, J., post, at p. 7.) In Communities for a
    Better Environment, we held an agency‟s discretionary decision on “exactly how
    the existing physical conditions without the project can most realistically be
    measured” is reviewed for substantial evidence supporting the measurement
    method. (48 Cal.4th at p. 328, italics added.) We did not hold or imply agencies
    enjoy equivalent discretion under CEQA and the CEQA Guidelines to omit all
    analysis of the project‟s impacts on existing conditions and measure impacts only
    against conditions projected to prevail 20 or 30 years in the future, so long as their
    projections are realistic.
    Nor does the concurring and dissenting opinion‟s citation to Cherry Valley
    Pass Acres & Neighbors v. City of Beaumont (2010) 
    190 Cal.App.4th 316
     aid its
    argument. (Conc. & dis. opn. of Baxter, J., post, at p. 6.) The cited decision
    merely applied Communities for a Better Environment to determine that a water
    allocation approximating the property‟s recent historical use constituted a realistic
    measure of existing conditions. (Cherry Valley Pass Acres & Neighbors v. City of
    Beaumont, supra, 190 Cal.App.4th at pp. 337-338.) The case has nothing to say
    about an agency‟s decision to omit an existing conditions analysis and employ
    solely a baseline of conditions in the distant future.
    8
    The Courts of Appeal, however, have since addressed the future conditions
    baseline question directly in Sunnyvale West Neighborhood Assn. v. City of
    Sunnyvale City Council (2010) 
    190 Cal.App.4th 1351
     (Sunnyvale West), Madera
    Oversight Coalition, Inc. v. County of Madera (2011) 
    199 Cal.App.4th 48
    , and
    Pfeiffer v. City of Sunnyvale City Council (2011) 
    200 Cal.App.4th 1552
     (Pfeiffer),
    as well as in the present litigation.
    In Sunnyvale West, the appellate court held inadequate an EIR‟s analysis of
    a road extension project‟s traffic impacts because it used projected conditions in
    the year 2020 as its only baseline, even though EIR preparation began in 2007 and
    the project was approved in 2008. (Sunnyvale West, supra, 190 Cal.App.4th at pp.
    1358, 1360, 1370.) While acknowledging that Guidelines section 15125(a) and
    our decision in Communities for a Better Environment provided agencies
    discretion on how best to measure existing conditions, the court concluded
    “nothing in the law authorizes environmental impacts to be evaluated only against
    predicted conditions more than a decade after EIR certification and project
    approval.” (Sunnyvale West, at p. 1380.) The use of a single future conditions
    baseline was per se a violation of CEQA; it was not a discretionary choice that
    could be justified by substantial evidence. (Sunnyvale West, at p. 1383.)
    The Sunnyvale West court observed that, although in its view the baseline
    for analysis of a project‟s direct impacts must be existing conditions, “discussions
    of the foreseeable changes and expected future conditions . . . may be necessary to
    an intelligent understanding of a project‟s impacts over time and full compliance
    with CEQA.” (Sunnyvale West, supra, 190 Cal.App.4th at p. 1381.) In particular,
    the effects of the project under predicted future conditions, themselves projected in
    part on the assumption that other approved or planned projects will proceed, are
    appropriately considered in an EIR‟s analysis of cumulative impacts (see Cal.
    Code Regs., tit. 14, § 15130) or in a discussion comparing the project to the “no
    9
    project alternative” (id., § 15126.6, subd. (e)). (Sunnyvale West, at pp. 1381-
    1382.) So long as the EIR evaluated the project‟s significant impacts on existing
    conditions, the court saw “no problem” with also examining the effect on
    projected future conditions “where helpful to an intelligent understanding of the
    project‟s environmental impacts.” (Id. at p. 1382.)
    The court in Madera Oversight Coalition, Inc. v. County of Madera,
    considering the adequacy of an EIR‟s discussion of a mixed-use property
    development‟s traffic impacts, followed Sunnyvale West on the baseline question.
    Without extensive additional statutory analysis, the court adopted from Sunnyvale
    West the rule that agencies “do not have the discretion to adopt a baseline that uses
    conditions predicted to occur on a date subsequent to the certification of the EIR.”
    (Madera Oversight Coalition, Inc. v. County of Madera, supra, 199 Cal.App.4th at
    p. 90.)
    In Pfeiffer, a different panel of the same court that decided Sunnyvale West
    reviewed the EIR for a medical center‟s expansion project. The EIR‟s analysis of
    traffic impacts compared, for various road segments and intersections in the
    project‟s vicinity, existing traffic conditions with various growth and project
    scenarios. (Pfeiffer, supra, 200 Cal.App.4th at p. 1571.) Holding the plaintiffs
    had not shown this analysis inadequate under CEQA, Pfeiffer distinguished
    Sunnyvale West as involving the use of only a future conditions baseline, whereas
    in Pfeiffer “the traffic baselines included in the EIR were not limited to projected
    traffic conditions in the year 2020, but also included existing conditions and the
    traffic growth anticipated from approved but not yet constructed developments.”
    (Pfeiffer, at p. 1573.)
    The appellate court in the present case flatly disagreed with the Sunnyvale
    West analysis. Noting that Guidelines section 15125(a) states the EIR‟s
    description of existing environmental conditions “ „normally‟ ” serves as the
    10
    baseline for analysis of project impacts, the court reasoned that “[t]o state the
    norm is to recognize the possibility of departure from the norm” and concluded the
    Sunnyvale West court erred in finding in the law an absolute rule against use of
    projected future conditions as the baseline. In the lower court‟s view, future
    conditions are properly used as a baseline if the projections on which they are
    based are reliable and their use “provide[s] information that is relevant and permits
    informed decisionmaking.”
    We conclude CEQA and the Guidelines dictate a rule less restrictive than
    Sunnyvale West‟s but more restrictive than that articulated by the Court of Appeal
    below. Projected future conditions may be used as the sole baseline for impacts
    analysis if their use in place of measured existing conditions—a departure from
    the norm stated in Guidelines section 15125(a)—is justified by unusual aspects of
    the project or the surrounding conditions. That the future conditions analysis
    would be informative is insufficient, but an agency does have discretion to
    completely omit an analysis of impacts on existing conditions when inclusion of
    such an analysis would detract from an EIR‟s effectiveness as an informational
    document, either because an analysis based on existing conditions would be
    uninformative or because it would be misleading to decision makers and the
    public.
    Before addressing the use of a future conditions baseline, we pause to
    clarify some potentially confusing aspects of the standard analysis, in which the
    project‟s impacts are assessed against existing environmental conditions. First,
    although most projects for which an EIR is prepared do not yet exist or are not yet
    in operation at the time the EIR is written, it is common for an EIR‟s impacts
    analysis to assume, counterfactually, that the project exists and is in full operation
    at the time the environmental analysis is conducted. (See, e.g., Gilroy Citizens for
    Responsible Planning v. City of Gilroy (2006) 
    140 Cal.App.4th 911
    , 916-917, 933
    11
    [EIR analyzed impacts on city‟s existing central business district of developing
    proposed outlying retail center]; Association of Irritated Residents v. County of
    Madera (2003) 
    107 Cal.App.4th 1383
    , 1389, 1393-1394 [EIR analyzed impacts on
    wildlife of replacing existing farm fields with proposed dairy operation]; cf.
    1 Kostka & Zischke, Practice Under the Cal. Environmental Quality Act
    (Cont.Ed.Bar 2d ed. 2008) Significant Environmental Effects, § 13.21, p. 635 (rev.
    3.13) [EIR must analyze significant effects of entire project, including phases to be
    implemented later].) In such an analysis, the EIR attempts to predict the impacts a
    project would have on the existing environment if approved and implemented.
    CEQA‟s wording reflects the fact that projects generally are not yet operating
    when an EIR is prepared: an EIR must be prepared for any project “that may
    have” a significant environmental effect (§ 21100, subd. (a)); the report‟s purpose
    is to inform the public and decision makers as to the effects a proposed project “is
    likely to have” on the environment (§ 21061); and the “environment” referred to is
    the set of physical conditions in the area “which will be affected” by the project
    (§ 21060.5).
    Second, we note that in appropriate circumstances an existing conditions
    analysis may take account of environmental conditions that will exist when the
    project begins operations; the agency is not strictly limited to those prevailing
    during the period of EIR preparation. An agency may, where appropriate, adjust
    its existing conditions baseline to account for a major change in environmental
    conditions that is expected to occur before project implementation. In so adjusting
    its existing conditions baseline, an agency exercises its discretion on how best to
    define such a baseline under the circumstance of rapidly changing environmental
    conditions. (Communities for a Better Environment, 
    supra,
     48 Cal.4th at p. 328.)
    As we explained in our earlier decision, CEQA imposes no “uniform, inflexible
    rule for determination of the existing conditions baseline,” instead leaving to a
    12
    sound exercise of agency discretion the exact method of measuring the existing
    environmental conditions upon which the project will operate. (Ibid.) Interpreting
    the statute and regulations in accord with the central purpose of an EIR—“to
    provide public agencies and the public in general with detailed information about
    the effect which a proposed project is likely to have on the environment”
    (§ 21061)—we find nothing precluding an agency from employing, under
    appropriate factual circumstances, a baseline of conditions expected to obtain at
    the time the proposed project would go into operation.
    For example, in an EIR for a new office building, the analysis of impacts on
    sunlight and views in the surrounding neighborhood might reasonably take
    account of a larger tower already under construction on an adjacent site at the time
    of EIR preparation. For a large-scale transportation project like that at issue here,
    to the extent changing background conditions during the project‟s lengthy
    approval and construction period are expected to affect the project‟s likely
    impacts, the agency has discretion to consider those changing background
    conditions in formulating its analytical baseline. Contrary to Justice Baxter‟s view
    (conc. & dis. opn. of Baxter, J., post, at p. 15), such a date-of-implementation
    baseline does not share the principal problem presented by a baseline of conditions
    expected to prevail in the more distant future following years of project operation
    — it does not omit impacts expected to occur during the project‟s early period of
    operation.
    Is it ever appropriate for an EIR‟s significant impacts analysis to use
    conditions predicted to prevail in the more distant future, well beyond the date the
    project is expected to begin operation, to the exclusion of an existing conditions
    baseline? We conclude agencies do have such discretion. The key, again, is the
    EIR‟s role as an informational document. To the extent a departure from the
    “norm[]” of an existing conditions baseline (Guidelines, § 15125(a)) promotes
    13
    public participation and more informed decisionmaking by providing a more
    accurate picture of a proposed project‟s likely impacts, CEQA permits the
    departure. Thus an agency may forego analysis of a project‟s impacts on existing
    environmental conditions if such an analysis would be uninformative or
    misleading to decision makers and the public.5
    Parenthetically, we stress that the burden of justification articulated above
    applies when an agency substitutes a future conditions analysis for one based on
    existing conditions, omitting the latter, and not to an agency‟s decision to examine
    project impacts on both existing and future conditions. As the Sunnyvale West
    court observed, a project‟s effects on future conditions are appropriately
    considered in an EIR‟s discussion of cumulative effects and in discussion of the no
    project alternative. (Sunnyvale West, supra, 190 Cal.App.4th at pp. 1381-1382.)6
    5      Amicus curiae South Coast Air Quality Management District provides a
    hypothetical example of factual conditions in which use of an existing conditions
    baseline would arguably mask potentially significant project impacts that would be
    revealed by using a future conditions baseline. In this illustration, an existing
    industrial facility currently emits an air pollutant in the amount of 1,000 pounds
    per day. By the year 2020, if no new project is undertaken at the facility,
    emissions of the pollutant are projected to fall to 500 pounds per day due to
    enforcement of regulations already adopted and to turnover in the facility‟s vehicle
    fleet. The operator proposes to use the facility for a new project that will emit 750
    pounds per day of the pollutant upon implementation and through at least 2020.
    An analysis comparing the project‟s emissions to existing emissions would
    conclude the project would reduce pollution and thus have no significant adverse
    impact, while an analysis using a baseline of projected year 2020 conditions would
    show the project is likely to increase emissions by 250 pounds per day, a
    (presumably significant) 50 percent increase over baseline conditions.
    6      A cumulative impacts analysis focuses on the effects of the proposed
    project together with other projects causing related impacts and may rely on
    projections of future conditions that are expected to contribute to a cumulative
    adverse effect (Cal. Code Regs., tit. 14, § 15130, subds. (a)(1), (b)), while analysis
    of the no project alternative includes a discussion of “what would be reasonably
    (footnote continued on next page)
    14
    But nothing in CEQA law precludes an agency, as well, from considering both
    types of baseline—existing and future conditions—in its primary analysis of the
    project‟s significant adverse effects. (Pfeiffer, supra, 200 Cal.App.4th at p. 1573;
    Woodward Park Homeowners Assn., Inc. v. City of Fresno (2007) 
    150 Cal.App.4th 683
    , 707.) The need for justification arises when an agency chooses
    to evaluate only the impacts on future conditions, foregoing the existing conditions
    analysis called for under the CEQA Guidelines.
    The need to justify omission of an existing conditions analysis derives in
    part from the CEQA Guidelines, which clearly establish that the norm for an EIR
    is analysis against a baseline of existing conditions. In addition to Guidelines
    section 15125(a), which expressly so provides, the Guidelines provide that an EIR
    “should normally limit its examination to changes in the existing physical
    conditions in the affected area,” considering both direct and indirect effects and
    “giving due consideration to both the short-term and long-term effects” of the
    project. (Cal. Code Regs., tit. 14, § 15126.2, subd. (a), italics added.) Moreover,
    the Guidelines explain that “[t]he no project alternative analysis is not the baseline
    for determining whether the proposed project‟s environmental impacts may be
    significant, unless it is identical to the existing environmental setting analysis
    which does establish that baseline (see Section 15125).” (Cal. Code Regs., tit. 14,
    § 15126.6, subd. (e)(1).) While the latter regulation does not absolutely prohibit
    the use of a future conditions baseline where appropriate, it makes clear that
    normally the baseline for determining a project‟s significant adverse impacts is not
    (footnote continued from previous page)
    expected to occur in the foreseeable future if the project were not approved, based
    on current plans and consistent with available infrastructure and community
    services” (Cal. Code Regs., tit. 14, § 15126.6, subd. (e)(2)).
    15
    the same as the no project alternative, which takes into account future changes in
    the environment reasonably expected to occur if the project is not approved. (Id.,
    subd. (e)(2), (3)(C).)
    The CEQA Guidelines establish the default of an existing conditions
    baseline even for projects expected to be in operation for many years or decades.
    That a project will have a long operational life, by itself, does not justify an
    agency‟s failing to assess its impacts on existing environmental conditions. For
    such projects as for others, existing conditions constitute the norm from which a
    departure must be justified—not only because the CEQA Guidelines so state, but
    because using existing conditions serves CEQA‟s goals in important ways.
    Even when a project is intended and expected to improve conditions in the
    long term—20 or 30 years after an EIR is prepared—decision makers and
    members of the public are entitled under CEQA to know the short- and medium-
    term environmental costs of achieving that desirable improvement. These costs
    include not only the impacts involved in constructing the project but also those the
    project will create during its initial years of operation. Though we might
    rationally choose to endure short- or medium-term hardship for a long-term,
    permanent benefit, deciding to make that trade-off requires some knowledge about
    the severity and duration of the near-term hardship. An EIR stating that in 20 or
    30 years the project will improve the environment, but neglecting, without
    justification, to provide any evaluation of the project‟s impacts in the meantime,
    does not “giv[e] due consideration to both the short-term and long-term effects” of
    the project (Cal. Code Regs., tit. 14, § 15126.2, subd. (a)) and does not serve
    CEQA‟s informational purpose well. The omission of an existing conditions
    analysis must be justified, even if the project is designed to alleviate adverse
    environmental conditions over the long term.
    16
    In addition, existing environmental conditions have the advantage that they
    can generally be directly measured and need not be projected through a predictive
    model. However sophisticated and well-designed a model is, its product carries
    the inherent uncertainty of every long-term prediction, uncertainty that tends to
    increase with the period of projection. For example, if future population in the
    project area is projected using an annual growth multiplier, a small error in that
    multiplier will itself be multiplied and compounded as the projection is pushed
    further into the future. The public and decision makers are entitled to the most
    accurate information on project impacts practically possible, and the choice of a
    baseline must reflect that goal.
    Finally, use of existing conditions as a baseline makes the analysis more
    accessible to decision makers and especially to members of the public, who may
    be familiar with the existing environment but not technically equipped to assess a
    projection into the distant future. As an amicus curiae observes, “[a]nyone can
    review an EIR‟s discussion of current environmental conditions and determine
    whether [it] comports with that person‟s knowledge and experience of the world.”
    But “[i]n a hypothetical future world, the environment is what the statisticians say
    it is.” Quantitative and technical descriptions of environmental conditions have a
    place in CEQA analysis, but an agency must not create unwarranted barriers to
    public understanding of the EIR by unnecessarily substituting a baseline of
    projected future conditions for one based on actual existing conditions. (See
    Laurel Heights Improvement Assn. v. Regents of University of California (1988)
    
    47 Cal.3d 376
    , 392 [EIR allows the public to “know the basis on which its
    responsible officials either approve or reject environmentally significant action,”
    thereby promoting “informed self-government”].)
    Justice Baxter‟s concurring and dissenting opinion proposes a significantly
    more lax rule, similar to that espoused by the Court of Appeal below, under which
    17
    a future conditions baseline may be employed, in lieu of one based on existing
    environmental conditions, so long as it is “a realistic measure of the physical
    conditions without the proposed project” projected at the agency‟s chosen future
    date. (Conc. & dis. opn. of Baxter, J, post, at p. 7.) As discussed earlier, such a
    rule cannot be derived from Communities for a Better Environment or the other
    authority cited for it. Moreover, it would drain Guidelines section 15125(a)‟s last
    sentence (providing that existing environmental conditions “will normally
    constitute the baseline physical conditions by which a lead agency determines
    whether an impact is significant”) of virtually all prescriptive effect. Perhaps most
    important, it would sanction the unwarranted omission of information on years or
    decades of a project‟s environmental impacts and open the door to gamesmanship
    in the choice of baselines.
    Under the rule proposed in Justice Baxter‟s opinion, agencies evaluating
    projects intended to exist and operate for many decades could seemingly choose a
    baseline of conditions from any period of the project‟s expected operations, 15, 30
    or 60 years in the future, so long as the agency‟s projections were supported by
    reasonably reliable data and predictive modeling. Existing environmental
    conditions would constitute the “normal[]” baseline for an EIR (Guidelines
    § 15125(a))—except for any case where the agency chose a different baseline.
    Agencies would be empowered routinely to omit discussion of short- and medium-
    term operational effects, preparing EIRs that told the public and decision makers
    only what impacts could be expected decades down the road. An agency that
    wished to hide significant adverse impacts expected to occur in the project‟s initial
    years of operation could choose to analyze the project‟s environmental effects
    only at some more distant period, when changes in background conditions might
    mask or swamp the adverse effects seen in the shorter term. That no intentional
    hiding of likely impacts appears in this case does not negate the potential for
    18
    manipulation of the baseline under a rule that provides agencies unbounded
    discretion in the choice.
    Contrary to Justice Baxter‟s claim, our holding here does not impose any
    “wasteful” or “additional” substantive requirement on agencies. (Conc. & dis.
    opn. of Baxter, J., post, at p. 18.) We hold only that agencies normally must do
    what Guidelines section 15125(a) expressly requires — compare the project‟s
    impacts to existing environmental conditions, as that term is broadly understood,
    to determine their significance. The question we would have an agency ask in
    choosing a baseline is not, “Would an existing conditions analysis add information
    to a future conditions analysis?” It is, “Do we have a reason to omit the existing
    conditions analysis and substitute one based on future conditions?” Of course,
    where an agency concludes an analysis of impacts on future conditions is also
    needed in any portion of the EIR, it may include such an analysis. But any
    duplication of effort therein involved is not a product of this decision.
    For all these reasons, we hold that while an agency preparing an EIR does
    have discretion to omit an analysis of the project‟s significant impacts on existing
    environmental conditions and substitute a baseline consisting of environmental
    conditions projected to exist in the future, the agency must justify its decision by
    showing an existing conditions analysis would be misleading or without
    informational value. Sunnyvale West Neighborhood Assn. v. City of Sunnyvale
    City Council, supra, 
    190 Cal.App.4th 1351
    , and Madera Oversight Coalition, Inc.
    v. County of Madera, supra, 
    199 Cal.App.4th 48
    , are disapproved insofar as they
    hold an agency may never employ predicted future conditions as the sole baseline
    for analysis of a project‟s environmental impacts.
    Because the standard articulated here involves a primarily factual
    assessment, the agency‟s determination is reviewed only for substantial evidence
    supporting it. (Vineyard Area Citizens for Responsible Growth, Inc. v. City of
    19
    Rancho Cordova, 
    supra,
     40 Cal.4th at p. 435.) If substantial evidence supports an
    agency‟s determination that an existing conditions impacts analysis would provide
    little or no relevant information or would be misleading as to the project‟s true
    impacts, a reviewing court may not substitute its own judgment on this point for
    that of the agency. (Ibid.)
    B. The Expo Authority’s Use of a Year 2030 Baseline
    1. Traffic congestion analysis
    As proposed in the EIR, the Expo Phase 2 project will cross several streets
    at grade rather than with bridges or tunnels. To analyze the resulting impacts on
    traffic congestion, the Expo Authority used the following method:
    (1) For numerous street intersections in the vicinity, the agency directly
    observed existing congestion in 2007-2008, measuring it as the average delay in
    travel through each intersection during the morning and afternoon peak travel
    periods. The delay was expressed in terms of “Level of Service” (LOS), ranging
    from LOS A (free flow) to LOS F (extreme congestion).7
    (2) Using MTA‟s traffic projection model, which incorporates regional
    growth projections from the Southern California Association of Governments, the
    Expo Authority predicted the LOS for each intersection in the year 2030 if the
    Expo Phase 2 project is not built (and assuming no other transit improvements
    along the project corridor).
    7      For signalized intersections, delay at LOS A is less than or equal to 10
    seconds, at LOS B it is between 10 and 20 seconds, at LOS C it is between 20 and
    35 seconds, at LOS D it is between 35 and 55 seconds, at LOS E it is between 55
    and 80 seconds, and at LOS F it is greater than 80 seconds. The LOS thresholds
    are lower for unsignalized intersections.
    20
    (3) For each intersection studied, the Expo Authority then predicted the
    LOS in the year 2030 if the Expo Phase 2 project is built and operated. These
    projections took into account automobile trip reductions expected to result from
    the project and additional peak hour trips to drop off or pick up passengers at
    stations, as well as the impact of stoppages at grade crossings as each train passes.
    (4) For each intersection, the predicted year 2030 LOS with the project was
    compared to the predicted year 2030 LOS without the project and the significance
    of any impact assessed. An adverse impact on delay was considered significant if
    the project was projected to cause service to deteriorate from LOS A, B, C, or D to
    LOS E or F or, for those intersections projected to be at LOS E or F in 2030
    without the project, if the project would increase delay by four seconds or more.
    Using this method, the EIR projects some additional local traffic congestion
    in 2030 due to the project, but none rising above the significance thresholds just
    described. For example, at the intersection of Stewart Street and Olympic
    Boulevard, vehicles in the year 2030 are expected to experience a morning peak
    period delay of 34.2 seconds absent the project and 49.0 seconds with the project,
    but this 14.8-second increase in delay is not considered significant because it only
    moves the intersection from LOS C to LOS D, and not into the unsatisfactory
    categories of LOS E and F. At 20th Street and Olympic Boulevard, the project is
    expected to cause an additional 0.8 seconds of delay, considered insignificant
    because it does not change the projected LOS, which is expected to be
    unsatisfactory (LOS E) in 2030 even without the project, and falls below the four-
    second significance threshold. Several other intersections fit these patterns of
    insignificant adverse impact, while at many other intersections the project is
    projected to reduce traffic delay in 2030, due in part to intersection improvements
    proposed in conjunction with the transit line.
    21
    2. Air pollution analysis
    Based on projections of an increase in vehicle miles traveled in the region,
    the EIR predicts an increase in air pollution emissions by 2030 if the Expo Phase 2
    project is not built. The project would result in fewer vehicle miles traveled, in
    comparison to the no-build alternative, and hence in fewer emissions in 2030. By
    reducing vehicle travel and the resulting emissions below those otherwise
    expected, project implementation “would have a beneficial impact on regional
    pollutant levels over the life of the project . . . .”
    3. Explanation of baseline choice
    In the introduction to the EIR‟s factual findings, the Expo Authority
    explains that it found use of a future conditions baseline for traffic and air quality
    impacts analysis necessary “so that the public and the decision makers may
    understand the future impacts on traffic and air quality of approving and not
    approving the project.” The EIR continues: “The evaluation of future traffic and
    air quality conditions utilizes adopted official demographic and [sic] projections
    for the project area and region. Past experience with the adopted demographic
    projections indicate that it is reasonable to assume that the population of the
    project area and the region will continue to increase over the life of the project.
    The projected population increases will, in turn, result in increased traffic
    congestion and increased air emissions from mobile sources in the project area and
    in the region. [¶] For most of the environmental topics in the [EIR] and in these
    Findings, the Authority finds that existing environmental conditions are the
    appropriate baseline condition for the purpose of determining whether an impact is
    significant. However, the Authority finds that the existing physical environmental
    conditions (current population and traffic levels) do not provide a reasonable
    baseline for the purpose of determining whether traffic and air quality impacts of
    the Project are significant. The Authority is electing to utilize the future baseline
    22
    conditions for the purposes of determining the significance of impacts to traffic
    and air quality.”
    Further explanation of the baseline choice is provided in a later section on
    the EIR‟s methods for determining impacts: “A transportation project includes
    significant capital infrastructure and is intended to meet long-term needs. As a
    result, the permanent effects of those transportation projects are, and should be,
    evaluated based on a longer-term perspective that takes increases in population
    and programmed changes to the transportation system into account. Since the
    project is addressing both existing and long-term transportation shortfalls, that
    longer-term perspective should include reasonably foreseeable other
    improvements. [¶] For this project the long-term permanent impacts are evaluated
    against what is [sic] expected to be existing conditions in 2030. This assumes the
    planned growth (jobs and employment) and related funded transportation
    improvements as proposed in the [Southern California Association of
    Governments Regional Transportation Plan]. In addition, short-term impacts
    associated with the construction period (2011 to 2015) of the project have also
    been evaluated. [¶] . . . Because population and traffic are anticipated to increase
    over the life of the project, this approach provides the public and decision makers
    with a realistic evaluation of the significance of air quality and traffic impacts over
    the life of the project.”
    The Expo Authority‟s explanation of its baseline choice in its briefing
    places similar reliance on the inevitability of population and traffic growth in the
    project area: “It is undisputed that the population, employment and concomitant
    traffic congestion will continue to increase through 2030 on the west side.
    [Citation.] It is absurd to suggest that the Authority use 2007 population,
    employment and traffic to determine the Project‟s operational impacts when the
    2007 conditions will no longer exist when the Project is fully operational.”
    23
    4. Propriety of baseline choice
    We discern no substantial evidence supporting the Expo Authority‟s
    decision to omit an analysis of the project‟s traffic and air quality impacts on
    existing environmental conditions. Although the agency did not expressly find an
    existing conditions analysis would have been misleading or without informational
    value, its finding that for analysis of traffic congestion and air pollution impacts
    “existing physical environmental conditions . . . do not provide a reasonable
    baseline” may be construed as so asserting. Unfortunately, nothing in the record
    supports that determination, and without such evidence the Expo Authority cannot
    justify its decision to completely omit an analysis of the project‟s impacts on
    existing traffic congestion and air quality.
    The Expo Authority observes that “2007 conditions will no longer exist
    when the Project is fully operational.” As discussed earlier, CEQA allows an
    agency to adjust its existing conditions baseline to account for an important
    change that will occur between the time an EIR is prepared and the time of project
    implementation. (See pt. I.A., ante.) But the Expo Authority did not measure
    traffic congestion and air pollution impacts against existing environmental
    conditions when the project begins operations. The agency used no existing
    conditions baseline, adjusted or unadjusted, for analysis of these impacts, instead
    employing only a baseline of projected 2030 conditions.
    That the Expo Phase 2 project is “intended to meet long-term needs” for
    public transportation is an insufficient justification. By focusing solely on the
    project‟s operational impacts in the distant future, the EIR neglects to inform the
    public and decision makers explicitly of any operational impacts that could occur
    in the project‟s first 15 years of operation. (The only short-term impacts on traffic
    and air quality analyzed were those resulting from the project‟s construction.) The
    absence of such “due consideration to both the short-term and long-term effects”
    24
    of the project (Cal. Code Regs., tit. 14, § 15126.2, subd. (a)) threatens to deprive
    the EIR‟s users of the opportunity to weigh the project‟s environmental costs and
    benefits in an informed manner.
    Similarly, that project area population, traffic, and emissions of air
    pollutants are expected to continue increasing through and beyond 2030 does not
    justify the agency‟s failure to analyze operational impacts under earlier conditions.
    The expectation of change may make it important for the agency to also examine
    impacts under future conditions (whether in the significant impacts analysis, the
    cumulative impacts analysis, or the discussion of the no project alternative), but it
    does not constitute substantial evidence supporting a determination that an existing
    conditions analysis would be uninformative or misleading.
    Nor does the fact ridership is not expected to reach maximum levels
    immediately upon the transit line‟s opening constitute substantial evidence
    justifying the failure to examine impacts on existing conditions.8 The level of
    ridership on the proposed transit line is a characteristic of the project in operation,
    not a characteristic of the environmental baseline against which project impacts
    are measured. As noted earlier, an existing conditions analysis often assumes the
    8       The record does not indicate full ridership will first be achieved in 2030.
    The passage cited in the Expo Authority‟s brief, found in the EIR‟s discussion of
    parking impacts and mitigation along Colorado Avenue, reads as follows: “On
    opening day, 71 to 92 percent of the 2030 parking demand would be provided
    depending on the Preferred Alternative selected. This would be reasonably
    consistent with opening day ridership, which is estimated at approximately 77
    percent of the year 2030 forecasts.” While this makes clear ridership on opening
    day is expected to be below its ultimate maximum, it does not purport to predict
    how fast ridership will increase or when it will reach its full level, other than
    assuming that level will be reached by or before the year 2030. From common
    experience, one might expect fewer than 15 years will be needed for commuters to
    start using a new transit line.
    25
    project exists and is in full operation at the time the environmental analysis is
    conducted, measuring the likely impacts against a baseline of conditions existing
    at the time of environmental analysis. Thus the Expo Authority did not need to
    employ a baseline of predicted 2030 background conditions in order to measure
    the impacts of full ridership; those likely impacts could have been predicted
    against an existing conditions baseline. Justice Baxter‟s concurring and dissenting
    opinion, in suggesting the year 2030 baseline was chosen as representative of full
    ridership, ignores the fact that ridership is not a baseline condition but a
    characteristic of the project‟s operations. (Conc. & dis. opn. of Baxter, J., post, at
    p. 11.) In any event, neither the EIR, nor the Expo Authority‟s briefs, nor Justice
    Baxter‟s opinion explain whether ridership levels would affect the project‟s
    impacts on traffic congestion and air pollution, and if so, whether the effect would
    be positive or negative; the likelihood of changing ridership levels thus cannot be
    considered substantial evidence an existing conditions analysis—whatever
    ridership level it assumed—would be useless or misleading.
    In its brief, the Expo Authority states it “chose 2030 because when it issued
    the [notice of preparation of the EIR] in 2007, 2030 was the planning horizon for
    transportation projects in the adopted [Southern California Association of
    Governments] Regional Transportation Plan,” and asserts that federal law requires
    the use of this long-term perspective in planning for federally funded
    transportation projects. To the extent the agency is arguing that a technique used
    for planning under another statutory scheme necessarily satisfies CEQA‟s
    requirements for analysis of a project‟s impacts, we disagree. Except where
    CEQA or the CEQA Guidelines tie CEQA analysis to planning done for a
    different purpose (see, e.g., § 21081.2, subd. (a) [CEQA findings on traffic
    impacts not required for certain residential infill projects that are in compliance
    with other municipal plans and ordinances]), an EIR must be judged on its
    26
    fulfillment of CEQA‟s mandates, not those of other statutes. And while we try to
    interpret CEQA in a manner consistent with other planning schemes (see Vineyard
    Area Citizens for Responsible Growth, Inc. v. City of Rancho Cordova, 
    supra,
     40
    Cal.4th at pp. 432-434), no issue of conflict or incompatibility arises here.
    Nothing prevents an agency preparing an EIR from analyzing the impacts of a
    project against an existing conditions baseline even if the agency has also planned
    under other statutes for the project‟s long-term operation. Moreover, the use of
    multiple baselines for direct impacts analysis does not violate CEQA (see Pfeiffer,
    supra, 200 Cal.App.4th at p. 1573; Woodward Park Homeowners Assn., Inc. v.
    City of Fresno, supra, 150 Cal.App.4th at p. 707), and even when the EIR uses
    solely an existing conditions baseline for direct impacts analysis, available
    information about the longer term impacts of the project, together with other
    foreseeable developments, is appropriately incorporated into the EIR under the
    rubric of a cumulative impacts analysis (Cal. Code Regs., tit. 14, § 15130). There
    is thus no necessary connection between use of a year 2030 horizon for
    transportation planning generally and the agency‟s choice of conditions in that
    year as the sole baseline for project impacts analysis under CEQA.
    In summary, the administrative record does not offer substantial evidence
    to support the Expo Authority‟s decision to limit its analysis of project impacts on
    traffic congestion and air quality to predicted impacts in the year 2030, to the
    exclusion of likely impacts on conditions existing when the EIR was prepared or
    when the project begins operation.
    5. Prejudice
    An omission in an EIR‟s significant impacts analysis is deemed prejudicial
    if it deprived the public and decision makers of substantial relevant information
    about the project‟s likely adverse impacts. Although an agency‟s failure to
    27
    disclose information called for by CEQA may be prejudicial “regardless of
    whether a different outcome would have resulted if the public agency had
    complied” with the law (§ 21005, subd. (a)), under CEQA “there is no
    presumption that error is prejudicial” (id., subd. (b)). Insubstantial or merely
    technical omissions are not grounds for relief. (Environmental Protection
    Information Center v. California Dept. of Forestry & Fire Protection, 
    supra,
     44
    Cal.4th at pp. 485-486.) “A prejudicial abuse of discretion occurs if the failure to
    include relevant information precludes informed decisionmaking and informed
    public participation, thereby thwarting the statutory goals of the EIR process.”
    (Kings County Farm Bureau v. City of Hanford (1990) 
    221 Cal.App.3d 692
    , 712.)
    With regard to the analysis of Expo Phase 2‟s traffic congestion impacts,
    we conclude the EIR‟s use exclusively of a future conditions baseline had no such
    prejudicial effect. Although the EIR failed to analyze the project‟s impacts on
    existing traffic congestion, it did include an extensive analysis of year 2030
    congestion effects, finding no significant adverse impacts. That detailed analysis
    demonstrates the lack of grounds to suppose the same analysis performed against
    existing traffic conditions would have produced any substantially different
    information.
    The EIR revealed that project impacts on congestion at intersections along
    the chosen rail route are expected in most cases to be favorable in 2030, that most
    of the adverse impacts expected are small, and that even the few relatively large
    adverse impacts expected would not, if applied to existing conditions, result in
    significant changes in delay status.9 Although Neighbors has argued that
    9     For the majority of the more than 100 intersection/peak period
    combinations studied, the project‟s expected impact in 2030 is favorable or
    nonexistent. Where the predicted impact is adverse, it is generally minor,
    (footnote continued on next page)
    28
    intersections expected to reach unsatisfactory status by 2030 without the project
    might do so earlier because of project impacts, the EIR showed that those
    intersections would experience favorable, or in one instance adverse but very
    minor, impacts in 2030 due to the project.10 Design changes reducing delay are
    built into the project at many intersections, and the expected gradual increase in
    traffic generally could not reasonably be thought likely to result in substantially
    larger project impacts on congestion under existing conditions than under 2030
    conditions.11 In these particular factual circumstances, the EIR‟s omission did not
    (footnote continued from previous page)
    exceeding 10 seconds in only seven instances. And of the 10 currently satisfactory
    intersections (those in LOS status A through D) on which the rail project is
    expected to have the greatest adverse impacts in 2030, including the seven on
    which the projected 2030 impact exceeds 10 seconds, none are currently close
    enough to LOS E so that the 2030 impact, if applied to existing conditions, would
    put the intersection into unsatisfactory status. Only two currently satisfactory
    intersections are within 10 seconds of the LOS E threshold, and the project is
    projected to affect delay favorably at both.
    10      Five intersection/peak period combinations along the proposed transit line
    meet the criteria of being currently in a satisfactory LOS and projected to turn
    unsatisfactory by 2030 in the project‟s absence. For four of the five, the project‟s
    2030 impact on congestion is expected to be favorable, reducing delay in amounts
    ranging from 1.1 seconds to 30.1 seconds. The single projected adverse impact in
    this group is very small, 0.8 seconds. And since the existing morning peak delay
    at that intersection (20th Street and Olympic Boulevard) is 42.6 seconds, the
    adverse project impact under existing conditions would have to be 12.4 seconds,
    or more than 15 times the adverse impact in 2030, to put the intersection over the
    55-second threshold into LOS E. To posit such an extreme difference in impacts
    would be unsupported speculation.
    11      The record shows that, baseline conditions aside, the project‟s operations
    may differ somewhat on opening day from later periods, in that ridership on the
    transit line is expected initially to be only 77 percent of its eventual level. As
    noted earlier, however, an existing conditions impacts analysis ordinarily assumes,
    counterfactually, that the project is in full operation. And even if an existing
    conditions analysis assumed 77 percent ridership, no substantial difference in
    impacts would be likely. The rail project‟s favorable effect on project area traffic
    (footnote continued on next page)
    29
    “preclude[] informed decisionmaking and informed public participation.” (Kings
    County Farm Bureau v. City of Hanford, supra, 221 Cal.App.3d at p. 712.)
    We reach the same conclusion as to the analysis of air quality impacts.
    Based on the prediction that operation of the Expo Phase 2 project would reduce
    the vehicle miles traveled in the project area and hence reduce emissions of
    pollutants, the EIR concluded project implementation “would have a beneficial
    impact on regional pollutant levels over the life of the project . . . .” But the
    project will begin reducing vehicle miles travelled as soon as it starts operating, as
    some of those who would otherwise drive decide to take the new train. Under the
    EIR‟s logic, to which Neighbors raises no objection other than the choice of a
    baseline, the project‟s impact on air quality will thus be beneficial throughout its
    operation, not only in 2030. The EIR‟s formal use of a year 2030 baseline for this
    analysis was thus an insubstantial, technical error that cannot be considered
    prejudicial. (Environmental Protection Information Center v. California Dept. of
    Forestry & Fire Protection, 
    supra,
     44 Cal.4th at pp. 486-488.)
    To comply fully with CEQA‟s informational mandate, the Expo Authority
    should have analyzed the project‟s effects on existing traffic congestion and air
    quality conditions. Under the specific circumstances of this case, however, its
    failure to do so did not deprive agency decision makers or the public of substantial
    information relevant to approving the project, and is therefore not a ground for
    setting that decision aside.
    (footnote continued from previous page)
    is projected to be modest even at full ridership: a reduction of 0.38 percent in
    vehicle miles traveled in 2030. Even if the 77 percent initial ridership implies that
    initially the project will reduce vehicle miles traveled only by 0.29 percent, there
    are no grounds to believe such an extremely minor difference (0.09 percent) could
    substantially alter the project impacts on existing congestion at the individual
    intersections studied.
    30
    II. Adequacy of Mitigation Measure for Spillover Parking Effects
    As proposed in the EIR, the Expo Phase 2 project does not include
    construction of parking facilities at several stations. The EIR recognizes that some
    transit patrons will nevertheless attempt to park near these stations, and near-
    station streets where parking is neither time limited nor restricted to those with
    residential permits “could be impacted by spillover parking.” To mitigate this
    potential impact, the EIR proposed, and the agency adopted, a series of measures.
    On-street parking in areas where spillover effects are anticipated will be monitored
    before and for six months after the opening of the transit line. If a parking
    shortage results, MTA will help the responsible local jurisdiction establish an
    appropriate permit parking program, for which MTA will pay the signage and
    administrative costs. If a permit program is inappropriate for the area, MTA “will
    work with the local jurisdictions” to decide on another option, such as time-
    restricted, metered, or shared parking arrangements. By means of this mitigation
    measure, the EIR concludes, any adverse spillover parking effect will be rendered
    less than significant.
    Neighbors contends this mitigation measure is insufficiently enforceable
    because it depends on the cooperation of municipal agencies having jurisdiction
    over parking in the vicinity of the stations. CEQA, however, allows an agency to
    approve or carry out a project with potential adverse impacts if binding mitigation
    measures have been “required in, or incorporated into” the project or if “[t]hose
    changes or alterations are within the responsibility and jurisdiction of another
    public agency and have been, or can and should be, adopted by that other agency.”
    (§ 21081, subd. (a); see Cal. Code Regs., tit. 14, § 15091, subd. (b) [findings to
    this effect “shall be supported by substantial evidence in the record”].) The Expo
    Authority made both findings as to its spillover parking mitigation measure, and
    both findings are supported by substantial evidence.
    31
    Under the adopted mitigation measure, MTA is required to monitor parking
    in the potentially affected neighborhoods, to pay for a residential permit parking
    program where station spillover has resulted in a street parking shortage, and to
    assist in developing other measures where a residential permit program is
    inappropriate. But as MTA cannot institute street parking restrictions without the
    cooperation of the local municipalities, some part of the mitigation, to the extent it
    is needed, will indeed be the responsibility of other public agencies, which “can
    and should” (§ 21081, subd. (a)(2)) adopt parking programs and restrictions to
    alleviate pressure from commuters using the new transit line.
    Neighbors relies on Federation of Hillside & Canyon Associations v. City
    of Los Angeles (2000) 
    83 Cal.App.4th 1252
    , 1260-1262, in which the appellate
    court found a city‟s proposed measures to mitigate the transportation impacts of a
    general plan framework were inadequate. The transportation plan involved in that
    case, however, was designed to mitigate the effects of massive population and
    employment growth planned for the city and would have required $12 billion from
    various sources, of which the city‟s own portion far exceeded its available funds.
    (Id. at p. 1256.) The city thus “acknowledged in the [mitigation plan] that there
    was great uncertainty as to whether the mitigation measures would ever be funded
    or implemented” (id. at p. 1261), leading the court to find no substantial evidence
    that enforceable mitigation measures had been incorporated into or were required
    by the project.
    The circumstances in Federation of Hillside & Canyon Associations are not
    comparable to those here, where the mitigation measure at issue involves only the
    monitoring of parking near several transit stations and, if a shortage develops, the
    cooperative implementation of one or more relatively low-cost solutions. While
    the Expo Authority and MTA cannot guarantee local governments will cooperate
    to implement permit parking programs or other parking restrictions, the record
    32
    supports the conclusion these municipalities “can and should” (§ 21081, subd.
    (a)(2)) do so. Neighbors‟s speculation a municipality might not agree to a permit
    parking program—which MTA would pay for and which would benefit the
    municipality‟s own residents—is not sufficient to show the agency violated CEQA
    by adopting this mitigation measure. (See City of Marina v. Board of Trustees of
    California State University (2006) 
    39 Cal.4th 341
    , 364-365 [the finding that
    mitigation through sharing the cost of necessary improvements with the
    responsible agency is infeasible was not justified by speculation that the agency
    might not agree to undertake the improvements].)
    DISPOSITION
    The judgment of the Court of Appeal is affirmed.
    WERDEGAR, J.
    WE CONCUR:
    KENNARD, J.
    CORRIGAN, J.
    33
    CONCURRING AND DISSENTING OPINION BY BAXTER, J.
    Enacted by the Legislature in 1970, the California Environmental Quality
    Act (CEQA; Pub. Resources Code,1 § 21000 et seq.) aims to enhance the
    environmental quality of the state and promote long-term protection of the
    environment. (§ 21001.) To achieve these objectives, CEQA establishes a
    comprehensive review process for analyzing the potential environmental impacts
    of a proposed project and assessing how such impacts might be mitigated.
    Inasmuch as the review process can be quite lengthy and involved, the Legislature
    has declared it our state policy that the public agencies responsible for carrying out
    the process must do so “in the most efficient, expeditious manner,” so as to
    conserve the available financial, governmental, and other resources for application
    toward mitigation efforts. (§ 21003, subd. (f).) It is also the Legislature‟s intent
    that courts “shall not” interpret the statutory and regulatory requirements of CEQA
    “in a manner which imposes procedural or substantive requirements beyond those
    explicitly stated in [CEQA] or in the state guidelines.” (§ 21083.1.)
    1      All further statutory references are to this code unless otherwise indicated.
    1
    The majority‟s analysis of the baseline issue fails to honor these legislative
    prerogatives.2 The upshot of that analysis is this: An environmental impact report
    (EIR) may omit an analysis of a proposed project‟s impacts on existing conditions
    only when its inclusion “would detract from [the] EIR‟s effectiveness as an
    informational document.” (Lead opn., ante, at p. 11.) The majority‟s categorical
    rule means that, notwithstanding the particular nature and circumstances of a
    proposed project, a lead agency abuses its discretion when it evaluates
    environmental impacts with a baseline of projected future conditions in lieu of an
    existing conditions baseline, even though selection of the former is reasonable
    under the circumstances and substantial evidence supports the analysis. In short,
    even if an EIR‟s analysis of impacts using a future conditions baseline, standing
    alone, would provide a realistic measure of a project‟s impacts that allows for
    informed decisionmaking and public participation, the majority mandates that the
    EIR also undertake and include an existing conditions analysis, so long as such an
    analysis would not in fact diminish the effectiveness of the document. (Lead opn.,
    ante, at p. 11.)
    Although it is easy to see the wastefulness of requiring an existing
    conditions analysis when a future conditions analysis provides a realistic
    assessment of a project‟s significant adverse effects, there are several legal reasons
    why the majority‟s holding is in error. Most notably, the majority‟s restrictions on
    agency discretion find no support in CEQA or in the regulations promulgated
    thereunder. (See pt. II.A., post.) In addition, the restrictions are contrary to our
    2      I use the term “majority” to refer to those portions of the lead opinion‟s
    analysis in which Justice Liu concurs. (See conc. & dis. opn. of Liu, J., post, at
    pp. 1-3, 5.)
    2
    decisions recognizing an agency‟s discretion in selecting a baseline and case law
    requiring deferential review of agency decisions. (See ibid.)
    Apart from these legal defects, the majority‟s analysis is objectionable for
    the further reason that it adds a significant level of complexity and uncertainty to
    an already arduous environmental review process. To begin with, the stated
    restrictions are ambiguous and create opportunities for litigation over their
    applicability. Moreover, the ease of alleging an abuse of discretion under the
    majority‟s analysis is likely to prompt challenges whenever an existing conditions
    baseline is omitted, causing delays that may add significantly to a project‟s costs
    or derail it altogether. (See pt. II.B., post.) The mere threat of such challenges
    may prompt lead agencies to engage in existing conditions analyses as a matter of
    course, even if such exercises would not materially improve public disclosure or
    informed decisionmaking, and this despite the declared state policy requiring that
    the review process be conducted efficiently and expeditiously in order to conserve
    financial and governmental resources. (See ibid.) That the majority needlessly
    complicates and protracts the CEQA review process is most unfortunate, for both
    the public and the environment.
    In sum, I concur in the ultimate affirmance of the Court of Appeal
    judgment, which upheld certification of the EIR for the proposed light rail project
    at issue (Expo Phase 2). I also concur in the majority‟s rejection of the spillover
    parking contentions of plaintiff Neighbors for Smart Rail (Neighbors). But I
    dissent from the majority‟s analysis of the baseline issue and its conclusion that
    the lead agency (Expo Authority) abused its discretion in approving the EIR‟s use
    of an analytic baseline of traffic and air quality conditions projected to exist in the
    year 2030 (the 2030 baseline), in lieu of a baseline of the conditions existing in
    2007 when the notice of preparation of the EIR was published.
    3
    As a major infrastructure project designed specifically to address projected
    long-term increases in traffic congestion and air pollution, Expo Phase 2‟s very
    operation will, over time, achieve environmental objectives and efficiencies in
    complete alignment with CEQA‟s goals of enhancing and protecting the
    environment in this state. The majority does not disagree that the traffic and air
    quality conditions in 2007 will no longer exist when Expo Phase 2 is fully
    operational. But despite Expo Authority‟s reliance on this reality as a justification
    for omitting an impacts analysis based on the 2007 conditions, the majority
    proceeds to fault the agency for failing to analyze the conditions projected to exist
    eight years after that date, when Expo Phase 2 is scheduled to begin operations in
    2015. (See lead opn., ante, at pp. 24, 27.) The unfairness of today‟s decision is
    stunning: the majority finds an abuse of discretion based on the lead agency‟s
    failure to use a baseline that is nowhere mentioned in the CEQA statutes,
    regulations, or case law, and that no agency or member of the public ever
    advocated in the administrative review process below.
    Unlike the majority, I conclude, consistent with the statutory and decisional
    law governing review in CEQA proceedings, that the record amply supports Expo
    Authority‟s use of the 2030 baseline in place of an existing conditions baseline.
    (See pt. I., post.) The record also confirms that substantial evidence supports the
    2030 baseline as a realistic baseline for measuring the project‟s operational
    impacts on traffic and air quality conditions. (Ibid.)
    I.
    The basic purpose of an EIR is “to provide public agencies and the public
    in general with detailed information about the effect which a proposed project is
    likely to have on the environment; to list ways in which the significant effects of
    such a project might be minimized; and to indicate alternatives to such a project.”
    (§ 21061; see also § 21002.1, subd. (a).) CEQA defines a “significant effect on
    4
    the environment” as meaning “a substantial, or potentially substantial, adverse
    change in the environment.” (§ 21068.)
    In order to provide meaningful information to the decision makers and the
    public, an EIR must clearly and accurately identify the effects of the proposed
    project as distinguished from nonproject effects. To determine if a project is likely
    to have a significant effect on the environment, the lead agency “must use some
    measure of the environment‟s state absent the project.” (Communities for a Better
    Environment v. South Coast Air Quality Management Dist. (2010) 
    48 Cal.4th 310
    ,
    315 (Communities for a Better Environment).) The “environment” means the
    physical conditions existing within the area “which will be affected by a proposed
    project.” (§ 21060.5.)
    As relevant here, “[a]n EIR must include a description of the physical
    environmental conditions in the vicinity of the project, as they exist at the time the
    notice of preparation is published, or if no notice of preparation is published, at the
    time environmental analysis is commenced, from both a local and regional
    perspective. This environmental setting will normally constitute the baseline
    physical conditions by which a lead agency determines whether an impact is
    significant.” (Cal. Code Regs., tit. 14, § 15125, subd. (a), italics added;3 see also
    Guidelines, § 15126.2, subd. (a).) In using the word “normally,” Guidelines
    section 15125, subdivision (a) (Guidelines section 15125(a)), “necessarily
    contemplates” that physical conditions at a point in time other than the two
    specified may constitute the appropriate baseline or environmental setting.
    3       Henceforth, all references to “Guidelines” are to the CEQA Guidelines in
    title 14 of the California Code of Regulations.
    5
    (Cherry Valley Pass Acres & Neighbors v. City of Beaumont (2010) 
    190 Cal.App.4th 316
    , 336 (Cherry Valley).)
    In Communities for a Better Environment, we emphasized that “ „the date
    for establishing a baseline cannot be a rigid one. Environmental conditions may
    vary from year to year and in some cases it is necessary to consider conditions
    over a range of time periods.‟ ” (Communities for a Better Environment, supra, 48
    Cal.4th at pp. 327-328.) An agency‟s selection of a baseline is, fundamentally, a
    factual determination of how to realistically measure the physical conditions
    without the proposed project. (Id. at p. 328; see Cherry Valley, supra,
    190 Cal.App.4th at pp. 336-337.) Although Communities for a Better
    Environment did not approve the use of projected future conditions as the sole
    baseline for evaluating environmental impacts, neither did it prohibit such use or
    otherwise impose restrictions on an agency‟s discretion to omit an existing
    conditions baseline.4 This should be obvious from the fact that the decision is the
    only support the majority cites for its purported holding that an agency may base
    an EIR‟s impacts analysis exclusively on the conditions “expected to obtain” —
    i.e., projected to obtain — when a proposed project begins operating. (Lead opn.,
    ante, at pp. 12-13, italics added; see pt. II.B., post.) The important takeaway from
    Communities for a Better Environment is our recognition that, while flexibility in
    establishing a baseline must be allowed, the selected baseline must result in a
    reliable evaluation of a project‟s impacts.
    4      As the majority acknowledges, to the extent Court of Appeal decisions have
    held or suggested that sole use of a projected future conditions baseline is
    forbidden, they are wrong. (E.g., Pfeiffer v. City of Sunnyvale City Council (2011)
    
    200 Cal.App.4th 1552
    ; Madera Oversight Coalition, Inc. v. County of Madera
    (2011) 
    199 Cal.App.4th 48
    ; Sunnyvale West Neighborhood Assn. v. City of
    Sunnyvale City Council (2010) 
    190 Cal.App.4th 1351
    .)
    6
    Generally, an abuse of discretion is established under CEQA “if the agency
    has not proceeded in a manner required by law or if the determination or decision
    is not supported by substantial evidence.” (§ 21168.5.) Because the language of
    Guidelines section 15125(a) clearly contemplates that an agency may depart from
    the norm of an existing conditions analysis, the proper inquiry is whether the
    agency acted reasonably given the nature and circumstances of the project, and
    whether substantial evidence supports its selected alternative baseline as a realistic
    measure of the physical conditions without the proposed project that provides an
    impacts analysis allowing for informed decisionmaking and public participation.
    (§ 21168.5; see Communities for a Better Environment, 
    supra,
     48 Cal.4th at
    pp. 315, 322.) A reviewing court will “indulge all reasonable inferences from the
    evidence that would support the agency‟s determinations and resolve all conflicts
    in the evidence in favor of the agency‟s decision.” (Save Our Peninsula
    Committee v. Monterey County Bd. of Supervisors (2001) 
    87 Cal.App.4th 99
    , 117
    (Save Our Peninsula).)
    “[A]s with all CEQA factual determinations,” the selection of a baseline is
    a discretionary determination reviewed “for support by substantial evidence.”
    (Communities for a Better Environment, 
    supra,
     48 Cal.4th at p. 328; see Fat v.
    County of Sacramento (2002) 
    97 Cal.App.4th 1270
    , 1278 [decision not to deviate
    from the norm also reviewed for substantial evidence].) Substantial evidence
    supporting a predicted baseline may consist of reasonable assumptions and expert
    evaluations that are supported by facts. (§ 21080, subd. (e)(1); Guidelines,
    § 15384, subd. (b); see Eureka Citizens for Responsible Government v. City of
    Eureka (2007) 
    147 Cal.App.4th 357
    , 371-372; Save Our Peninsula, supra,
    87 Cal.App.4th at p. 120.) The requirement that an agency‟s decision be
    supported by substantial evidence helps to ensure that a particular baseline will not
    7
    be selected unless there is evidence of a solid and credible nature warranting its
    use.
    During the lengthy administrative review process here, plaintiff Neighbors
    complained the EIR should have used a baseline of projected conditions in the
    year 2035 to allow for a proper evaluation of traffic congestion and air quality
    impacts. In filing this lawsuit, however, Neighbors switched tactics and now
    claims the EIR is deficient in failing to use the regulatory baseline norm of the
    physical conditions existing “at the time the notice of preparation is published”
    (Guidelines, § 15125(a)), namely, a 2007 baseline. No deficiency appears.
    The EIR explicitly states that Expo Phase 2 is designed, inter alia, to
    “provide high-capacity transit service,” to “[a]ccommodate existing population
    and employment growth and transit-supportive land use densities,” to “[p]rovide
    an effective transit alternative to the current and expected increase in roadway
    congestion in the corridor,” and to “[r]ealize environmental benefits associated
    with increased transit usage, such as improved air quality and energy efficiencies.”
    Thus, unlike projects that are industrial or commercial in nature, Expo Phase 2
    was conceived specifically to alleviate traffic congestion and improve air quality
    in full alignment with CEQA‟s objectives to enhance environmental quality and
    promote long-term protection of the environment. (See § 21001; Mountain Lion
    Foundation v. Fish & Game Com. (1997) 
    16 Cal.4th 105
    , 112.)
    As pertinent here, the EIR presented and relied upon state-of-the-art
    forecasting models that accounted for existing traffic conditions, approved
    population and employment growth projections, and resulting changes in traffic.
    These models project, among other things, that between 2005 and 2030, daily
    vehicle miles traveled within the study area will increase by 27 percent (31 percent
    to 32 percent during peak hours), and daily vehicle hours will increase by 74
    percent (93 percent to 105 percent during peak hours). In light of this and other
    8
    data, including the forecast that the transit system‟s opening day ridership in 2015
    will be only 77 percent of the ridership in 2030, Expo Authority approved the
    EIR‟s exclusive use of a 2030 baseline to evaluate the traffic and air quality
    impacts that would be associated with the system‟s usage at that time.5
    Significantly, no one here disputes the validity of the forecasting models
    and data used to project the physical conditions in 2030 or the accuracy of the
    EIR‟s analysis of the transit system‟s operational impacts using the 2030 baseline.
    As the EIR reflects, it evaluated the system‟s impacts on traffic utilizing an
    independently developed forecasting model6 that has been subjected to extensive
    peer review and certified by the Federal Transit Administration for use in
    environmental documents. Notably, the model was updated and refined
    specifically for use in the EIR, in close coordination with that federal agency.
    Likewise, there is no evidence that the 2030 baseline was selected to
    manipulate the analysis of traffic congestion and air quality impacts. As even
    5      Consistent with CEQA requirements, Expo Authority reviewed the EIR at
    issue and approved its evaluation of Expo Phase 2‟s potential impacts and possible
    alternatives with an existing conditions baseline on all other environmental topics,
    including the impacts during the projected four-year construction period (2011-
    2015). (Guidelines, § 15125(a).) These topics included visual quality (aesthetics),
    biological resources (vegetation and wildlife), cultural resources (including
    archaeological and historical resources), paleontological resources, geology, soils,
    and seismicity, hydrology and water quality, land use and planning, noise and
    vibration, parks and community facilities, safety and security (including delay of
    emergency service vehicles when waiting for light rail vehicles to cross an
    intersection), socioeconomics (including potential displacement and relocation of
    housing, residents, and businesses), and energy resources. Expo Authority also
    reviewed the potential hazardous materials or conditions that could be
    encountered, given the existing conditions.
    6     The Los Angeles County Metropolitan Transit Authority developed the
    model with data inputs from a regional travel demand model developed by the
    Southern California Association of Governments.
    9
    Justice Werdegar acknowledges, use of the 2030 baseline resulted in an
    “extensive” and “detailed” analysis that demonstrates no grounds “to suppose the
    same analysis performed against existing traffic [and air quality] conditions would
    have produced any substantially different information.” (Lead opn., ante, at p.
    28.)
    Indulging all reasonable inferences from the evidence that support Expo
    Authority‟s determinations and resolving all evidentiary conflicts in favor of its
    decision (Save Our Peninsula Committee, supra, 87 Cal.App.4th at p. 117), and
    for the reasons below, I conclude the agency did not abuse its discretion in
    forgoing an existing conditions baseline in favor of a 2030 baseline to measure
    Expo Phase 2‟s operational impacts.
    Expo Phase 2 was specifically designed to alleviate expected increases in
    “roadway congestion” and to “realize environmental benefits . . . such as improved
    air quality” based on a 2030 transit planning horizon. Accordingly, Expo
    Authority could reasonably decide that an evaluation of the environmental
    conditions with and without the transit system in the year 2030, when the system
    will actually be operating, will allow for a meaningful understanding of its
    operational impacts on traffic and air quality. Certainly, the fact that state-of-the-
    art forecasting models predict substantial increases in the percentages of daily
    vehicle miles and vehicle hours from 2005 to 2030 provides ample basis for the
    agency‟s decision to dispense with an analysis based on 2007 traffic conditions
    which will no longer exist when the system is in operation. Given the
    uncontroverted expert projections showing that traffic conditions and congestion
    at the studied intersections will be worse in 2030 than in 2005 (and in 2007), it
    stands to reason that analyzing the system‟s operational impacts under the more
    congested conditions of 2030 is not only realistic, but yields a more
    environmentally rigorous measure of such impacts than an analysis based on the
    10
    outdated and less congested conditions existing in 2007. Selecting the 2030
    planning horizon as representative of operational conditions is logical for the
    additional reason that, despite the system‟s anticipated opening date of 2015,
    ridership at that point is projected to be at only 77 percent of the capacity
    anticipated in 2030.
    Moreover, as the validity of the forecasting models and the accuracy of the
    projected future conditions are not even in dispute, there can be no question that
    substantial evidence supported Expo Authority‟s predicted baseline. (Guidelines,
    § 15384, subd. (b); see Eureka Citizens for Responsible Government v. City of
    Eureka, supra, 147 Cal.App.4th at pp. 371-372; Save Our Peninsula, supra, 87
    Cal.App.4th at p. 120.) Indeed, Justice Werdegar‟s prejudice analysis confirms
    that the EIR‟s assessment of Expo Phase 2‟s impacts, using the 2030 baseline,
    fulfilled the essential purpose of an EIR to provide the decision makers and the
    public in general with “detailed information about the effect which [the] proposed
    project is likely to have on the environment.” (§ 21061; see also § 21002.1, subd.
    (a).)
    II.
    Instead of applying a straightforward abuse of discretion analysis, the
    majority holds: “Projected future conditions may be used as the sole baseline for
    impacts analysis if their use in place of measured existing conditions — a
    departure from the norm stated in Guidelines section 15125(a) — is justified by
    unusual aspects of the project or the surrounding conditions. That the future
    conditions analysis would be informative is insufficient, but an agency does have
    discretion to completely omit an analysis of impacts on existing conditions when
    inclusion of such an analysis would detract from an EIR’s effectiveness as an
    informational document, either because an analysis based on existing conditions
    would be uninformative or because it would be misleading to decision makers and
    11
    the public.” (Lead opn., ante, at p. 11, italics added.) Applying these rigid
    limitations, the majority concludes Expo Authority abused its discretion in
    approving the EIR‟s sole use of a 2030 baseline to measure Expo Phase 2‟s
    impacts on traffic and air quality.
    As explained below, the majority‟s analysis suffers from several significant
    flaws.
    A. The Majority’s Restrictions Find No Support in CEQA and are
    Contrary to Principles Governing Review of Agency Decisions
    First and foremost, the stated restrictions find no support in CEQA or its
    Guidelines. Apart from emphasizing Guideline language stating that existing
    physical conditions will “normally” constitute the baseline for an impacts analysis
    (Guidelines, § 15125(a)) and that a lead agency should “normally” limit its
    examination to changes in the existing physical conditions (Guidelines, § 15126.2,
    subd. (a)), the majority offers no statutory or regulatory basis, and no evidence of
    legislative intent, reflecting that an agency has no discretion to omit an existing
    conditions analysis unless such an analysis is so utterly devoid of value that it is
    uninformative or misleading. Without more, it is a stretch to construe the bare
    language of the Guidelines in this manner. Nor are the Guidelines reasonably
    susceptible of a construction that bars an agency from selecting a projected future
    conditions analysis in lieu of an existing conditions analysis when the former
    (1) reflects a rational selection given the nature and circumstances of the project;
    (2) is realistic and furnishes substantial relevant information about a project‟s
    significant effects; and (3) otherwise allows for informed decisionmaking and
    informed public participation.7
    7      The majority‟s citation to Guidelines section 15126.6, which requires an
    EIR to consider and discuss a range of reasonable alternatives to a proposed
    (footnote continued on next page)
    12
    In addition, the majority‟s restrictions do not align with the principle that an
    agency‟s selection of a baseline involves a discretionary determination of how to
    realistically measure a project‟s impacts. (See Communities for a Better
    Environment, 
    supra,
     48 Cal.4th at pp. 327-328.) When an agency reasonably
    relies on an alternative baseline, requiring an extra analysis with an existing
    conditions baseline is superfluous and runs counter to the CEQA principle that a
    reviewing court must defer to an agency‟s baseline selection when it is supported
    by the record, even if a different baseline would be equally reasonable — or
    perhaps even more reasonable — than the one selected. (See Vineyard Area
    Citizens for Responsible Growth, Inc. v. City of Rancho Cordova (2007) 
    40 Cal.4th 412
    , 435; Guidelines, § 15384, subd. (a).)
    The majority‟s abuse of discretion analysis also ignores the basic precepts
    that a certified EIR is presumed adequate and that “the party challenging the EIR
    has the burden of showing otherwise.” (Santa Clarita Organization for Planning
    the Environment v. County of Los Angeles (2007) 
    157 Cal.App.4th 149
    , 158; see
    Save Our Peninsula, supra, 87 Cal.App.4th at p. 117.) To wit, the majority finds
    the record lacking in substantial evidence justifying Expo Authority‟s decision to
    omit an analysis based on existing traffic congestion and air quality conditions.8
    Neighbors, however, never once contended during the administrative review
    process that the EIR was deficient for failing to use an existing conditions
    (footnote continued from previous page)
    project, adds nothing to the analysis. In the majority‟s own words, the Guideline
    “makes clear that normally the baseline for determining a project‟s significant
    adverse impacts is not the same as the no project alternative.” (Lead opn., ante, at
    pp. 15-16, first italics added.)]
    8       As explained, I conclude to the contrary. (See pt. I., ante.)
    13
    analysis. Although Neighbors‟s reply brief refers to other individuals who
    supposedly did so, none of the alleged comments or EIR responses thereto is
    included as part of the stipulated administrative record presented to the trial court
    or to this court. Hence, while the record‟s perceived inadequacy on this point
    comes as no surprise under the circumstances, what is startling is the majority‟s
    determination that the inadequacy inures to the benefit of the EIR‟s challenger.
    Finally, the majority‟s gloss on Guidelines section 15125(a) is entirely
    unnecessary to advance the environmental goals of CEQA. This is so because any
    baseline analysis — whether it evaluates the so-called norm of conditions existing
    before project approval or the conditions projected to exist at some future point —
    cannot be illusory and instead must be realistic and supported by substantial
    evidence. (§ 21168.5; Guidelines, § 15384; see Communities for a Better
    Environment, 
    supra,
     48 Cal.4th at p. 322.)
    B. The Majority’s Analysis Creates Uncertainties Regarding CEQA
    Compliance and Will Increase Project Costs and Delays
    The majority‟s analysis also suffers from ambiguity on a number of levels.
    In particular, the majority fails to clarify whether its restrictions apply to all
    departures from the regulatory baseline norm. By its terms, Guidelines section
    15125(a) designates only two environmental settings as the normal baseline: “at
    the time the notice of preparation is published, or if no notice of preparation is
    published, at the time environmental analysis is commenced.” The majority,
    however, identifies an alternative baseline based on a distinct third environmental
    setting — which it calls the “date-of-implementation baseline” — that reflects
    environmental conditions projected to exist “at the time the proposed project
    would go into operation.” (Lead opn., ante, at p. 13.) As the majority sees it, an
    agency might use such a baseline to analyze impacts when a project is not
    14
    scheduled to begin operations until years after the two events specified in
    Guidelines section 15125(a).9
    Although the majority finds that an agency has discretion to employ a date-
    of-implementation baseline, it fails to explicitly state whether or not its restrictions
    on agency discretion apply when such a baseline is selected. Logically, the
    restrictions should apply because the problems perceived by the majority
    regarding future conditions baselines in general would seem to apply equally to
    date-of-implementation baselines, particularly when a project takes several years
    to implement. (See lead opn., ante, at pp. 16-17 [criticizing use of predictive
    models to forecast future conditions, even though the validity and accuracy of the
    models used here are not disputed].)
    Moreover, the term “date of implementation” is nowhere mentioned in
    Guidelines section 15125(a), and the majority points to no other CEQA Guideline
    or statute providing a definition. While the majority offers its own definition of
    the term (the “environmental conditions that will exist when the project begins
    operations”; lead opn., ante, at p. 12), the absence of actual CEQA guidance on
    the issue creates uncertainty as to how much operation or implementation may be
    too much when determining the implementation date.
    9       In this case, for example, a so-called date-of-implementation baseline
    would have measured Expo Phase 2‟s predicted impacts on conditions projected to
    exist in 2015, a full eight years after the notice of preparation of an EIR was
    published in 2007. Although the majority essentially holds that use of a 2015
    baseline would have been a reasonable and proper exercise of discretion (see lead
    opn., ante, at pp. 12-13, 24, 27), there is no indication that view was shared by any
    agency or member of the public participating in the administrative review process.
    And as previously noted, Neighbors complained during the review process that a
    2035 baseline was required to accurately reflect the project‟s operational impacts.
    15
    Despite all this ambiguity, the majority appears to contemplate that use of a
    date-of-implementation baseline falls squarely within the existing conditions
    default. (Lead opn., ante, at pp. 12-13.) But the language of Guidelines section
    15125(a) is clear in designating only two environmental settings — both of which
    refer to physical conditions existing in the study area prior to a project’s approval
    — as the normal baseline. Under the guise of construing the physical conditions
    in those two environmental settings as encompassing conditions predicted to exist
    years in the future when a project is scheduled to begin operations, the majority
    accomplishes two things: while adding language to restrict an agency‟s discretion
    to omit an existing conditions analysis, the majority redefines what the Guideline
    means by “existing conditions,” so as to exempt this particular category of future
    conditions analysis from those restrictions. But that is not all — the majority
    further suggests that a date-of-implementation analysis is properly understood as
    including an analysis based on yet another distinct environmental setting not
    mentioned in Guidelines section 15125(a), i.e., “impacts expected to occur during
    the project‟s early period of operation.” (Lead opn., ante, at p. 13.) Although the
    judicial maneuvering on this point is creative, this court has no power to rewrite
    the Guideline so as to make it conform to a presumed intention that is not
    expressed. (See Vogel v. County of Los Angeles (1967) 
    68 Cal.2d 18
    , 26.)
    In any event, there is no need to rewrite Guidelines section 15125(a) to
    provide for ordinary discretionary use of a date-of-implementation baseline in lieu
    of an existing conditions baseline. Rather, consistent with the Guideline‟s express
    contemplation that an existing conditions analysis is the norm but not mandatory,
    we should simply adhere to precedent recognizing that an agency enjoys discretion
    to select an alternative baseline that is reasonably suited to the nature of the project
    under environmental review and the totality of the circumstances under which the
    project is expected to occur. (See Save Our Peninsula, supra, 87 Cal.App.4th at
    16
    pp. 125-126 [where environmental conditions vary over time it may be necessary
    to consider conditions over a range of time periods; in some cases, conditions
    closer to the date of project approval, which may be years after environmental
    review is commenced, may be more relevant to the impacts determination]; see
    also Communities for a Better Environment, 
    supra,
     48 Cal.4th at pp. 327-328
    [quoting Save Our Peninsula].) Moreover, as with any analysis of impacts on
    projected future physical conditions, a date-of-implementation analysis must be
    realistic and supported by substantial evidence.
    Another issue is that the majority‟s restrictions on the exercise of agency
    discretion appear rather difficult to meet. It is unclear how an agency might show
    that an existing conditions analysis would be “uninformative” or “misleading,”
    without actually conducting such an analysis. (Lead opn., ante, at p. 11.) It is also
    unclear just how “unusual” the aspects of a project or the surrounding conditions
    must be in order for a departure from the baseline norm to be “justified.” (Ibid.)
    Indeed, even though both the trial court and the Court of Appeal found substantial
    evidence supporting Expo Authority‟s use of a 2030 baseline instead of a 2007
    baseline (as do I), the majority‟s finding to the contrary demonstrates how
    rigorous the burden is intended to be.
    Finally, because the majority so narrowly circumscribes an agency‟s
    discretion to depart from the regulatory baseline norm, the burdens and delay
    associated with preparing and defending EIRs are likely to increase. That is, even
    though CEQA expressly permits use of an alternative baseline in lieu of an
    existing conditions baseline, and even though use of an alternative baseline,
    standing alone, would allow for informed decisionmaking and public participation,
    the EIR must also include an analysis of the project‟s impacts on existing
    conditions unless its inclusion actually diminishes the EIR‟s effectiveness as an
    informational document. The majority‟s imposition of this extra analytical
    17
    requirement is wasteful and directly at odds with the dual legislative commands
    that courts shall not interpret CEQA or the Guidelines in a manner that imposes
    additional substantive requirements (§ 21083.1), and that agencies must not
    engage in unnecessary and costly administrative processes that do not materially
    improve public disclosure or informed decisionmaking (§ 21003, subd. (f)).
    III.
    In sum, it cannot be disputed that a lead agency‟s “determination of the
    proper baseline for a project can be difficult and controversial, particularly when
    the physical conditions in the vicinity of the project are subject to fluctuations” or
    other significant changes. (Cherry Valley, supra, 190 Cal.App.4th at p. 337.) For
    all the reasons above, I conclude that an agency retains discretion to omit an
    analysis of a project‟s likely impacts with an existing conditions baseline, so long
    as the selected alternative of a projected future conditions baseline is supported by
    substantial evidence and results in a realistic impacts analysis that allows for
    informed decisionmaking and public participation.
    I further conclude that, given the nature and the circumstances of the light
    rail project at issue, Expo Authority reasonably selected a 2030 baseline in lieu of
    an existing conditions baseline for measuring the project‟s operational impacts on
    traffic congestion and air quality. Finally, in light of the undisputed validity of the
    forecasting models used to predict the future traffic and air quality conditions, I
    also conclude that substantial evidence supports the 2030 baseline as a realistic
    baseline for analyzing the project‟s impacts.
    BAXTER, J.
    WE CONCUR:
    CANTIL-SAKAUYE, C.J.
    CHIN, J.
    18
    CONCURRING AND DISSENTING OPINION BY LIU, J.
    I agree with the entirety of the court‟s well-reasoned opinion except for the
    conclusion that the error in the environmental impact report (EIR) was not
    prejudicial. On this record, I cannot confidently infer that the EIR‟s failure to
    measure impacts against a baseline of existing conditions did not deprive the
    public of relevant information about the project.
    The court‟s lucid analysis of the California Environmental Quality Act
    (CEQA) and applicable regulations firmly supports its holding that existing
    conditions comprise the normal baseline for measuring environmental impacts and
    that an agency may forego analyzing impacts against a baseline of existing
    conditions only “if such an analysis would be uninformative or misleading to
    decision makers and the public.” (Maj. opn., ante, at p. 14, fn. omitted.) Further,
    in light of Communities for a Better Environment v. South Coast Air Quality
    Management Dist. (2010) 
    48 Cal.4th 310
    , 328, the court is correct that “an
    existing conditions analysis may take account of environmental conditions that
    will exist when the project begins operations; the agency is not strictly limited to
    those prevailing during the period of EIR preparation.” (Maj. opn., ante, at p. 12;
    see id. at p. 13 [“[A] date-of-implementation baseline does not share the principal
    problem presented by a baseline of conditions expected to prevail in the more
    1
    distant future following years of project operation — it does not omit impacts
    expected to occur during the project‟s early period of operation.”].)
    Here, the Exposition Metro Line Construction Authority (Expo Authority)
    used a baseline of existing conditions to measure most of the predicted effects of
    the light-rail project, but it used a baseline of conditions projected to exist in 2030
    to measure the project‟s expected impacts on traffic congestion and air quality. It
    is undisputed that the agency properly considered what the long-term impacts of
    the project would be in 2030. The issue is whether the agency properly considered
    those long-term impacts to the exclusion of any short-term impacts. In measuring
    traffic and air quality impacts solely against projected conditions in 2030, the EIR
    provided no analysis of such impacts against a baseline of existing conditions,
    including conditions in 2015 when the project is scheduled to begin operations.
    As today‟s opinion explains: “Even when a project is intended and
    expected to improve conditions in the long term — 20 or 30 years after an EIR is
    prepared — decision makers and members of the public are entitled under CEQA
    to know the short- and medium-term environmental costs of achieving that
    desirable improvement. These costs include not only the impacts involved in
    constructing the project but also those the project will create during its initial years
    of operation. Though we might rationally choose to endure short- or medium-term
    hardship for a long-term, permanent benefit, deciding to make that trade-off
    requires some knowledge about the severity and duration of the near-term
    hardship.” (Maj. opn., ante, at p. 16.)
    Here, there is “no substantial evidence supporting the Expo Authority‟s
    decision to omit an analysis of the project‟s traffic and air quality impacts on
    existing environmental conditions.” (Maj. opn., ante, at p. 24.) “By focusing
    solely on the project‟s operational impacts in the distant future, the EIR neglects to
    inform the public and decision makers explicitly of any operational impacts that
    2
    could occur in the project‟s first 15 years of operation.” (Ibid.) The fact “that
    project area population, traffic, and emissions of air pollutants are expected to
    continue increasing through and beyond 2030 does not justify the agency‟s failure
    to analyze operational impacts under earlier conditions. The expectation of
    change may make it important for the agency to also examine impacts under
    future conditions . . . , but it does not constitute substantial evidence supporting a
    determination that an existing conditions analysis would be uninformative or
    misleading.” (Id. at p. 25.)
    After reaching these conclusions, the court holds that the EIR‟s failure to
    measure traffic and air quality impacts against existing conditions was harmless in
    this case. The court reasons that the EIR‟s extensive analysis of traffic congestion
    against conditions projected to exist in 2030 “demonstrates the lack of grounds to
    suppose the same analysis performed against existing traffic conditions would
    have produced any substantially different information.” (Maj. opn., ante, at p. 28.)
    But the fact that the project in 2030 is expected to have only a small effect on
    traffic congestion when compared to conditions in 2030 provides no reason to
    think that the project in 2015, at the start of operations, would have no greater
    impact when compared to conditions in 2015.
    The EIR compared measures of congestion in 2030 if the project is built to
    measures of congestion in 2030 if the project is not built. But the measures of
    congestion in 2030 if the project is not built reflect significant predicted increases
    in congestion due to population growth. Thus it is not surprising that the project is
    expected to have little impact on congestion in 2030 when measured against the
    heightened congestion expected in 2030. But that finding sheds no light on the
    extent or magnitude of the project‟s traffic impacts when it begins to operate in
    2015, before the predicted increase in congestion due to population growth from
    2015 to 2030. Without knowing how significant this transient impact on traffic
    3
    congestion might be, how are the public and decision makers to decide whether
    the short-term pain is worth the long-term gain promised by the light-rail project?
    It is not speculative to suggest that examining the project‟s impact on traffic
    congestion in 2015 would yield different results. When the project begins to
    operate, ridership is expected to be at 77 percent of its eventual level. During that
    initial period, there may be an influx of cars to areas around the new transit
    stations, as people come to ride the train. While it is reasonable to assume that the
    worsening of congestion solely due to population growth is a more-or-less linear
    process, it is also reasonable to posit that the increase in congestion if the project is
    built would take the shape of a curve, with an initial steep increase due to an influx
    of cars and riders that later tapers off as the public adjusts to the new system. At
    the very least, it is not implausible to think that things may get worse before they
    get better. As Neighbors for Smart Rail contends, focusing solely on impacts in
    2030 may mask earlier effects: intersections that are projected to worsen to
    critical levels of congestion if the project is not built may reach those levels sooner
    if the project is built. Or maybe not — but either way, CEQA does not permit the
    agency to simply leave the public guessing.
    The EIR‟s measure of air quality impacts suffers from the same problem.
    The EIR says the project, at full ridership, is expected to reduce vehicle miles
    traveled by 0.38 percent in 2030. The 0.38 percent figure reflects the differential
    between (a) vehicle miles driven in 2030 if the project is built and (b) vehicle
    miles driven in 2030 if the project is not built. From this, the court extrapolates
    that “the 77 percent initial ridership implies that initially the project will reduce
    vehicle miles traveled only by 0.29 percent.” (Maj. opn., ante, at p. 30, fn. 11.)
    The court derives the 0.29 percent figure by comparing (a) vehicle miles driven in
    2015 when the project begins operation with 77 percent ridership and (b) vehicle
    miles driven in 2030 if the project is not built. The proper comparison, however,
    4
    is the differential between (a) vehicle miles driven in 2015 when the project begins
    operation with 77 percent ridership and (b) vehicle miles driven in 2015 if the
    project is not built. As with traffic congestion, there is reason to believe the
    project might actually increase vehicle miles driven in the short term, as new
    transit stations attract people from near and far to ride the light rail. Further,
    without some analysis of the issue, we can only guess what portion of light-rail
    riders consists of people who would otherwise drive or ride cars to reach their
    destinations as opposed to new commuters who, but for the project, would not
    have traveled to their destinations at all, by car or otherwise.
    For the reasons above, I respectfully disagree with the court‟s conclusion
    that the EIR‟s failure to measure traffic congestion and air quality impacts against
    a baseline of existing conditions “did not deprive agency decision makers or the
    public of substantial information relevant to approving the project.” (Maj. opn.,
    ante, at p. 30.) In all other respects, I join the court‟s opinion.
    LIU, J.
    5
    See last page for addresses and telephone numbers for counsel who argued in Supreme Court.
    Name of Opinion Neighbors for Smart Rail v. Exposition Metro Line Construction Authority
    __________________________________________________________________________________
    Unpublished Opinion
    Original Appeal
    Original Proceeding
    Review Granted XXX 
    205 Cal.App.4th 552
    Rehearing Granted
    __________________________________________________________________________________
    Opinion No. S202828
    Date Filed: August 5, 2013
    __________________________________________________________________________________
    Court: Superior
    County: Los Angeles
    Judge: Thomas I. McKnew, Jr.
    __________________________________________________________________________________
    Counsel:
    Elkins Kalt Weintraub Reuben Gartside, John M. Bowman and C. J. Laffer for Plaintiff and Appellant.
    Alexander T. Henson for Sunnyvale West Neighborhood Association as Amicus Curiae on behalf of
    Plaintiff and Appellant.
    Nossaman, Robert D. Thornton, John J. Flynn III, Robert C. Horton, Lauren C. Valk and Lloyd W. Pellman
    for Defendants and Respondents.
    Cole Pedroza, Curtis A. Cole, Kenneth R. Pedroza and Matthew S. Levinson for Associated General
    Contractors of California as Amicus Curiae on behalf of Defendants and Respondents.
    Marcia L. Scully, Adam C. Kear; Brownstein Hyatt Farber Schreck, Lisabeth D. Rothman and Amy M.
    Steinfeld for Association of California Water Agencies as Amicus Curiae on behalf of Defendants and
    Respondents.
    Andrea Sheridan Ordin and John F. Krattli, County Counsel, Ronald W. Stamm, Principal Deputy County
    Counsel; Remy Moose Manley, Tiffany K. Wright, Sabrina V. Teller and Amanda R. Berlin for Real
    Parties in Interest.
    Remy, Thomas, Moose and Manley, Tiffany K. Wright; Woodruff, Spradlin & Smart, Bradley R. Hogin
    and Ricia R. Hager for Southern California Association of Governments, Foothill/Eastern Transportation
    Corridor Agency, San Joaquin Hills Transportation Corridor Agency, Metropolitan Water District of
    Southern California, San Joaquin Council of Governments, Madera County Transportation Commission,
    Riverside County Transportation Commission, Contra Costa Transportation Authority, Metro Gold Line
    Foothill Extension Construction Authority, Santa Clara Valley Transportation Authority, Orange County
    Transportation Authority and San Francisco County Transportation Authority as Amici Curiae on behalf of
    Defendants and Respondents and Real Parties in Interest.
    Page 2 – counsel continued
    Counsel:
    Cox, Castle& Nicholson, Michael H. Zischke, Andrew B. Sabey, Rachel R. Jones; Carmen A. Trutanich,
    City Attorney (Los Angeles), Andrew J. Nocas, Timothy McWilliams and Siegmund Shyu, Deputy City
    Attorneys; Marsha Jones Moutrie, City Attorney (Santa Monica), Joseph Lawrence, Deputy City Attorney;
    Carol Schwab, City Attorney (Culver City); John F. Kratli, County Counsel (Los Angeles), Thomas J.
    Faugnan, Assistant County Counsel, and Helen S. Parker, Principal Deputy County Counsel, for League of
    California Cities, California State Association of Counties, City of Los Angeles, County of Los Angeles,
    Culver City and City of Santa Monica as Amici Curiae on behalf of Defendants and Respondents and Real
    Parties in Interest.
    Kurt R. Wiese, Barbara B. Baird and Veera Tyagi for South Coast Air Quality Management District as
    Amicus Curiae on behalf of Defendants and Respondents and Real Parties in Interest.
    Sedgwick, Anna C. Shimko, Matthew D. Francois and Sigrid R. Waggener for California Building Industry
    as Amicus Curiae on behalf of Defendants and Respondents and Real Parties in Interest.
    Shute, Mihaly & Weinberger, Robert S. Perlmutter and Maya Kuttan for Sierra Club and Center for
    Biological Diversity as Amicus Curiae.
    Counsel who argued in Supreme Court (not intended for publication with opinion):
    John M. Bowman
    Elkins Kalt Weintraub Reuben Gartside
    2049 Century Park East, Suite 2700
    Los Angeles, CA 90067
    (310) 746-4400
    Robert D. Thornton
    Nossaman
    18101 Von Karman Avenue, Suite 1800
    Irvine, CA 92612
    (949) 833-7800