Revised Proposal on Updates to the CEQA Guidelines on Evaluating Transportation Impacts in CEQA

ON EVALUATING TRANSPORTATION

IMPACTS IN CEQA

TECHNICAL ADVISORY

December 2018

Contents

A. Introduction ...................................................................................................................................... 1

B. Background ....................................................................................................................................... 2

C. Technical Considerations in Assessing Vehicle Miles Traveled ......................................................... 4

1. Recommendations Regarding Methodology ................................................................................ 4

D. General Principles to Guide Consideration of VMT .......................................................................... 7

E. Recommendations Regarding Significance Thresholds .................................................................... 8

1. Screening Thresholds for Land Use Projects ............................................................................... 12

2. Recommended Numeric Thresholds for Residential, Office, and Retail Projects ....................... 15

3. Recommendations Regarding Land Use Plans ............................................................................ 18

4. Other Considerations .................................................................................................................. 19

F. Considering the Effects of Transportation Projects on Vehicle Travel ........................................... 19

1. Recommended Significance Threshold for Transportation Projects .......................................... 22

2. Estimating VMT Impacts from Transportation Projects ............................................................. 23

G. Analyzing Other Impacts Related to Transportation ...................................................................... 25

H. VMT Mitigation and Alternatives .................................................................................................... 26

Appendix 1. Considerations About Which VMT to Count ....................................................................... 29

Appendix 2. Induced Travel: Mechanisms, Research, and Additional Assessment Approaches ............ 32

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December 2018

A. Introduction

This technical advisory is one in a series of advisories provided by the Governor’s Office of Planning and

Research (OPR) as a service to professional planners, land use officials, and CEQA practitioners. OPR

issues technical assistance on issues that broadly affect the practice of land use planning and the

California Environmental Quality Act (CEQA) (Pub. Resources Code, § 21000 et seq.). (Gov. Code, §

65040, subds. (g), (l), (m).) The purpose of this document is to provide advice and recommendations,

which agencies and other entities may use at their discretion. This document does not alter lead agency

discretion in preparing environmental documents subject to CEQA. This document should not be

construed as legal advice.

Senate Bill 743

(Steinberg, 2013), which was codified in Public Resources Code section 21099, required

changes to the guidelines implementing CEQA (CEQA Guidelines) (Cal. Code Regs., Title 14, Div. 6, Ch. 3,

§ 15000 et seq.) regarding the analysis of transportation impacts. As one appellate court recently

explained: “During the last 10 years, the Legislature has charted a course of long-term sustainability

based on denser infill development, reduced reliance on individual vehicles and improved mass transit,

all with the goal of reducing greenhouse gas emissions. Section 21099 is part of that strategy . . . .”

(Covina Residents for Responsible Development v. City of Covina (2018) 21 Cal.App.5th 712, 729.)

Pursuant to Section 21099, the criteria for determining the significance of transportation impacts must

“promote the reduction of greenhouse gas emissions, the development of multimodal transportation

networks, and a diversity of land uses.” (Id., subd. (b)(1); see generally, adopted CEQA Guidelines, §

15064.3, subd. (b) [Criteria for Analyzing Transportation Impacts].) To that end, in developing the

criteria, OPR has proposed, and the California Natural Resources Agency (Agency) has certified and

adopted, changes to the CEQA Guidelines that identify vehicle miles traveled (VMT) as the most

appropriate metric to evaluate a project’s transportation impacts. With the California Natural Resources

Agency’s certification and adoption of the changes to the CEQA Guidelines, automobile delay, as

measured by “level of service” and other similar metrics, generally no longer constitutes a significant

environmental effect under CEQA. (Pub. Resources Code, § 21099, subd. (b)(3).)

This advisory contains technical recommendations regarding assessment of VMT, thresholds of

significance, and mitigation measures. Again, OPR provides this Technical Advisory as a resource for the

public to use at their discretion. OPR is not enforcing or attempting to enforce any part of the

recommendations contained herein. (Gov. Code, § 65035 [“It is not the intent of the Legislature to vest

in the Office of Planning and Research any direct operating or regulatory powers over land use, public

works, or other state, regional, or local projects or programs.”].)

This December 2018 technical advisory is an update to the advisory it published in April 2018. OPR will

continue to monitor implementation of these new provisions and may update or supplement this

advisory in response to new information and advancements in modeling and methods.

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December 2018

B. Background

VMT and Greenhouse Gas Emissions Reduction. Senate Bill 32 (Pavley, 2016) requires California to

reduce greenhouse gas (GHG) emissions 40 percent below 1990 levels by 2030, and Executive Order B-

16-12 provides a target of 80 percent below 1990 emissions levels for the transportation sector by 2050.

The transportation sector has three major means of reducing GHG emissions: increasing vehicle

efficiency, reducing fuel carbon content, and reducing the amount of vehicle travel. The California Air

Resources Board (CARB) has provided a path forward for achieving these emissions reductions from the

transportation sector in its 2016 Mobile Source Strategy. CARB determined that it will not be possible to

achieve the State’s 2030 and post-2030 emissions goals without reducing VMT growth. Further, in its

2018 Progress Report on California’s Sustainable Communities and Climate Protection Act, CARB found

that despite the State meeting its 2020 climate goals, “emissions from statewide passenger vehicle

travel per capita [have been] increasing and going in the wrong direction,” and “California cannot meet

its [long-term] climate goals without curbing growth in single-occupancy vehicle activity.”

CARB also

found that “[w]ith emissions from the transportation sector continuing to rise despite increases in fuel

efficiency and decreases in the carbon content of fuel, California will not achieve the necessary

greenhouse gas emissions reductions to meet mandates for 2030 and beyond without significant

changes to how communities and transportation systems are planned, funded, and built.”

Thus, to achieve the State’s long-term climate goals, California needs to reduce per capita VMT. This can

occur under CEQA through VMT mitigation. Half of California’s GHG emissions come from the

transportation sector

, therefore, reducing VMT is an effective climate strategy, which can also result in

co-benefits.

Furthermore, without early VMT mitigation, the state may follow a path that meets GHG

targets in the early years, but finds itself poorly positioned to meet more stringent targets later. For

example, in absence of VMT analysis and mitigation in CEQA, lead agencies might rely upon verifiable

offsets for GHG mitigation, ignoring the longer-term climate change impacts resulting from land use

development and infrastructure investment decisions. As stated in CARB’s 2017 Scoping Plan:

“California’s future climate strategy will require increased focus on integrated land use planning

to support livable, transit-connected communities, and conservation of agricultural and other

lands. Accommodating population and economic growth through travel- and energy-efficient

land use provides GHG-efficient growth, reducing GHGs from both transportation and building

energy use. GHGs can be further reduced at the project level through implementing energy-

efficient construction and travel demand management approaches.”

(Id. at p. 102.)

California Air Resources Board (Nov. 2018) 2018 Progress Report on California’s Sustainable

Communities and Climate Protection Act, pp. 4, 5, available at

https://ww2.arb.ca.gov/sites/default/files/2018-11/Final2018Report_SB150_112618_02_Report.pdf

Id., p. 28.

See https://ca50million.ca.gov/transportation/

Fang et al. (2017) Cutting Greenhouse Gas Emissions Is Only the Beginning: A Literature Review of the

Co-Benefits of Reducing Vehicle Miles Traveled.

California Air Resources Board (Nov. 2017) California’s 2017 Climate Change Scoping Plan, p. 102,

available at https://www.arb.ca.gov/cc/scopingplan/scoping_plan_2017.pdf

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December 2018

In light of this, the 2017 Scoping Plan describes and quantifies VMT reductions needed to achieve our

long-term GHG emissions reduction goals, and specifically points to the need for statewide deployment

of the VMT metric in CEQA:

“Employing VMT as the metric of transportation impact statewide will help to ensure GHG

reductions planned under SB 375 will be achieved through on-the-ground development, and will

also play an important role in creating the additional GHG reductions needed beyond SB 375

across the State. Implementation of this change will rely, in part, on local land use decisions to

reduce GHG emissions associated with the transportation sector, both at the project level, and

in long-term plans (including general plans, climate action plans, specific plans, and

transportation plans) and supporting sustainable community strategies developed under SB

375.”

VMT and Other Impacts to Health and Environment. VMT mitigation also creates substantial benefits

(sometimes characterized as “co-benefits” to GHG reduction) in both in the near-term and the long-

term. Beyond GHG emissions, increases in VMT also impact human health and the natural environment.

Human health is impacted as increases in vehicle travel lead to more vehicle crashes, poorer air quality,

increases in chronic diseases associated with reduced physical activity, and worse mental health.

Increases in vehicle travel also negatively affect other road users, including pedestrians, cyclists, other

motorists, and many transit users. The natural environment is impacted as higher VMT leads to more

collisions with wildlife and fragments habitat. Additionally, development that leads to more vehicle

travel also tends to consume more energy, water, and open space (including farmland and sensitive

habitat). This increase in impermeable surfaces raises the flood risk and pollutant transport into

waterways.

VMT and Economic Growth. While it was previously believed that VMT growth was a necessary

component of economic growth, data from the past two decades shows that economic growth is

possible without a concomitant increase in VMT. (Figure 1.) Recent research shows that requiring

development projects to mitigate LOS may actually reduce accessibility to destinations and impede

economic growth.

8,9

Id. at p. 76.

Fang et al. (2017) Cutting Greenhouse Gas Emissions Is Only the Beginning: A Literature Review of the

Co-Benefits of Reducing Vehicle Miles Traveled, available at

https://ncst.ucdavis.edu/wp-

content/uploads/2017/03/NCST-VMT-Co-Benefits-White-Paper_Fang_March-2017.pdf.

Haynes et al. (Sept. 2015) Congested Development: A Study of Traffic Delays, Access, and Economic

Activity in Metropolitan Los Angeles, available at http://www.its.ucla.edu/wp-

content/uploads/sites/6/2015/11/Haynes_Congested-Development_1-Oct-2015_final.pdf.

Osman et al. (Mar. 2016) Not So Fast: A Study of Traffic Delays, Access, and Economic Activity in the

San Francisco Bay Area, available at http://www.its.ucla.edu/wp-

content/uploads/sites/6/2016/08/Taylor-Not-so-Fast-04-01-2016_final.pdf.

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December 2018

Figure 1. Kooshian and Winkelman (2011) VMT and Gross Domestic Product (GDP), 1960-2010.

C. Technical Considerations in Assessing Vehicle Miles Traveled

Many practitioners are familiar with accounting for VMT in connection with long-range planning, or as

part of the CEQA analysis of a project’s greenhouse gas emissions or energy impacts. This document

provides technical information on how to assess VMT as part of a transportation impacts analysis under

CEQA. Appendix 1 provides a description of which VMT to count and options on how to count it.

Appendix 2 provides information on induced travel resulting from roadway capacity projects, including

the mechanisms giving rise to induced travel, the research quantifying it, and information on additional

approaches for assessing it.

1. Recommendations Regarding Methodology

Proposed Section 15064.3 explains that a “lead agency may use models to estimate a project’s vehicle

miles traveled . . . .” CEQA generally defers to lead agencies on the choice of methodology to analyze

impacts. (Santa Monica Baykeeper v. City of Malibu (2011) 193 Cal.App.4th 1538, 1546; see Laurel

Heights Improvement Assn. v. Regents of University of California (1988) 47 Cal.3d 376, 409 [“the issue is

not whether the studies are irrefutable or whether they could have been better” … rather, the “relevant

issue is only whether the studies are sufficiently credible to be considered” as part of the lead agency’s

overall evaluation].)

This section provides suggestions to lead agencies regarding methodologies to

analyze VMT associated with a project.

Vehicle Types. Proposed Section 15064.3, subdivision (a), states, “For the purposes of this section,

‘vehicle miles traveled’ refers to the amount and distance of automobile travel attributable to a

project.” Here, the term “automobile” refers to on-road passenger vehicles, specifically cars and light

trucks. Heavy-duty truck VMT could be included for modeling convenience and ease of calculation (for

example, where models or data provide combined auto and heavy truck VMT). For an apples-to-apples

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comparison, vehicle types considered should be consistent across project assessment, significance

thresholds, and mitigation.

Residential and Office Projects. Tour- and trip-based approaches

offer the best methods for assessing

VMT from residential/office projects and for comparing those assessments to VMT thresholds. These

approaches also offer the most straightforward methods for assessing VMT reductions from mitigation

measures for residential/office projects. When available, tour-based assessment is ideal because it

captures travel behavior more comprehensively. But where tour-based tools or data are not available

for all components of an analysis, a trip-based assessment of VMT serves as a reasonable proxy.

Models and methodologies used to calculate thresholds, estimate project VMT, and estimate VMT

reduction due to mitigation should be comparable. For example:

• A tour-based assessment of project VMT should be compared to a tour-based threshold, or a

trip-based assessment to a trip-based VMT threshold.

• Where a travel demand model is used to determine thresholds, the same model should also be

used to provide trip lengths as part of assessing project VMT.

• Where only trip-based estimates of VMT reduction from mitigation are available, a trip-based

threshold should be used, and project VMT should be assessed in a trip-based manner.

When a trip-based method is used to analyze a residential project, the focus can be on home-based

trips. Similarly, when a trip-based method is used to analyze an office project, the focus can be on

home-based work trips.

When tour-based models are used to analyze an office project, either employee work tour VMT or VMT

from all employee tours may be attributed to the project. This is because workplace location influences

overall travel. For consistency, the significance threshold should be based on the same metric: either

employee work tour VMT or VMT from all employee tours.

For office projects that feature a customer component, such as a government office that serves the

public, a lead agency can analyze the customer VMT component of the project using the methodology

for retail development (see below).

Retail Projects. Generally, lead agencies should analyze the effects of a retail project by assessing the

change in total VMT

because retail projects typically re-route travel from other retail destinations. A

retail project might lead to increases or decreases in VMT, depending on previously existing retail travel

patterns.

See Appendix 1, Considerations About Which VMT to Count, for a description of these approaches.

See Appendix 1, Considerations About Which VMT to Count, “Assessing Change in Total VMT” section,

for a description of this approach.

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December 2018

Considerations for All Projects. Lead agencies should not truncate any VMT analysis because of

jurisdictional or other boundaries, for example, by failing to count the portion of a trip that falls outside

the jurisdiction or by discounting the VMT from a trip that crosses a jurisdictional boundary. CEQA

requires environmental analyses to reflect a “good faith effort at full disclosure.” (CEQA Guidelines, §

15151.) Thus, where methodologies exist that can estimate the full extent of vehicle travel from a

project, the lead agency should apply them to do so. Where those VMT effects will grow over time,

analyses should consider both a project’s short-term and long-term effects on VMT.

Combining land uses for VMT analysis is not recommended. Different land uses generate different

amounts of VMT, so the outcome of such an analysis could depend more on the mix of uses than on

their travel efficiency. As a result, it could be difficult or impossible for a lead agency to connect a

significance threshold with an environmental policy objective (such as a target set by law), inhibiting the

CEQA imperative of identifying a project’s significant impacts and providing mitigation where feasible.

Combining land uses for a VMT analysis could streamline certain mixes of uses in a manner disconnected

from policy objectives or environmental outcomes. Instead, OPR recommends analyzing each use

separately, or simply focusing analysis on the dominant use, and comparing each result to the

appropriate threshold. Recommendations for methods of analysis and thresholds are provided below.

In the analysis of each use, a mixed-use project should take credit for internal capture.

Any project that includes in its geographic bounds a portion of an existing or planned Transit Priority

Area (i.e., the project is within a ½ mile of an existing or planned major transit stop or an existing stop

along a high quality transit corridor) may employ VMT as its primary metric of transportation impact for

the entire project. (See Pub. Resources Code, § 21099, subds. (a)(7), (b)(1).)

Cumulative Impacts. A project’s cumulative impacts are based on an assessment of whether the

“incremental effects of an individual project are considerable when viewed in connection with the

effects of past projects, the effects of other current projects, and the effects of probable future

projects.” (Pub. Resources Code, § 21083, subd. (b)(2); see CEQA Guidelines, § 15064, subd. (h)(1).)

When using an absolute VMT metric, i.e., total VMT (as recommended below for retail and

transportation projects), analyzing the combined impacts for a cumulative impacts analysis may be

appropriate. However, metrics such as VMT per capita or VMT per employee, i.e., metrics framed in

terms of efficiency (as recommended below for use on residential and office projects), cannot be

summed because they employ a denominator. A project that falls below an efficiency-based threshold

that is aligned with long-term environmental goals and relevant plans would have no cumulative impact

distinct from the project impact. Accordingly, a finding of a less-than-significant project impact would

imply a less than significant cumulative impact, and vice versa. This is similar to the analysis typically

conducted for greenhouse gas emissions, air quality impacts, and impacts that utilize plan compliance as

a threshold of significance. (See Center for Biological Diversity v. Department of Fish & Wildlife (2015) 62

Cal.4

204, 219, 223; CEQA Guidelines, § 15064, subd. (h)(3).)

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D. General Principles to Guide Consideration of VMT

SB 743 directs OPR to establish specific “criteria for determining the significance of transportation

impacts of projects[.]” (Pub. Resources Code, § 21099, subd. (b)(1).) In establishing this criterion, OPR

was guided by the general principles contained within CEQA, the CEQA Guidelines, and applicable case

law.

To assist in the determination of significance, many lead agencies rely on “thresholds of significance.”

The CEQA Guidelines define a “threshold of significance” to mean “an identifiable quantitative,

qualitative

or performance level of a particular environmental effect, non-compliance with which

means the effect will normally be determined to be significant by the agency and compliance with

which means the effect normally will be determined to be less than significant.” (CEQA Guidelines, §

15064.7, subd. (a) (emphasis added).) Lead agencies have discretion to develop and adopt their own, or

rely on thresholds recommended by other agencies, “provided the decision of the lead agency to adopt

such thresholds is supported by substantial evidence.” (Id. at subd. (c); Save Cuyama Valley v. County of

Santa Barbara (2013) 213 Cal.App.4th 1059, 1068.) Substantial evidence means “enough relevant

information and reasonable inferences from this information that a fair argument can be made to

support a conclusion, even though other conclusions might also be reached.” (Id. at § 15384 (emphasis

added); Protect the Historic Amador Waterways v. Amador Water Agency (2004) 116 Cal.App.4th 1099,

1108-1109.)

Additionally, the analysis leading to the determination of significance need not be perfect. The CEQA

Guidelines describe the standard for adequacy of environmental analyses:

An EIR should be prepared with a sufficient degree of analysis to provide decision makers

with information which enables them to make a decision which intelligently takes

account of environmental consequences. An evaluation of the environmental effects of

a proposed project need not be exhaustive, but the sufficiency of an EIR is to be reviewed

in the light of what is reasonably feasible. Disagreement among experts does not make

an EIR inadequate, but the EIR should summarize the main points of disagreement among

the experts. The courts have looked not for perfection but for adequacy, completeness,

and a good faith effort at full disclosure.

(CEQA Guidelines, § 15151 (emphasis added).)

These general principles guide OPR’s recommendations regarding thresholds of significance for VMT set

forth below.

Generally, qualitative analyses should only be conducted when methods do not exist for undertaking a

quantitative analysis.

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December 2018

E. Recommendations Regarding Significance Thresholds

As noted above, lead agencies have the discretion to set or apply their own thresholds of significance.

(Center for Biological Diversity v. California Dept. of Fish & Wildlife (2015) 62 Cal.4th 204, 218-223 [lead

agency had discretion to use compliance with AB 32’s emissions goals as a significance threshold]; Save

Cuyama Valley v. County of Santa Barbara (2013) 213 Cal.App.4th at p. 1068.) However, Section 21099

of the Public Resources Code states that the criteria for determining the significance of transportation

impacts must promote: (1) reduction of greenhouse gas emissions; (2) development of multimodal

transportation networks; and (3) a diversity of land uses. It further directed OPR to prepare and develop

criteria for determining significance. (Pub. Resources Code, § 21099, subd. (b)(1).) This section provides

OPR’s suggested thresholds, as well as considerations for lead agencies that choose to adopt their own

thresholds.

The VMT metric can support the three statutory goals: “the reduction of greenhouse gas emissions, the

development of multimodal transportation networks, and a diversity of land uses.” (Pub. Resources

Code, § 21099, subd. (b)(1), emphasis added.) However, in order for it to promote and support all three,

lead agencies should select a significance threshold that aligns with state law on all three. State law

concerning the development of multimodal transportation networks and diversity of land uses requires

planning for and prioritizing increases in complete streets and infill development, but does not mandate

a particular depth of implementation that could translate into a particular threshold of significance.

Meanwhile, the State has clear quantitative targets for GHG emissions reduction set forth in law and

based on scientific consensus, and the depth of VMT reduction needed to achieve those targets has

been quantified. Tying VMT thresholds to GHG reduction also supports the two other statutory goals.

Therefore, to ensure adequate analysis of transportation impacts, OPR recommends using quantitative

VMT thresholds linked to GHG reduction targets when methods exist to do so.

Various legislative mandates and state policies establish quantitative greenhouse gas emissions

reduction targets. For example:

• Assembly Bill 32 (2006) requires statewide GHG emissions reductions to 1990 levels by 2020 and

continued reductions beyond 2020.

• Senate Bill 32 (2016) requires at least a 40 percent reduction in GHG emissions from 1990 levels

by 2030.

• Pursuant to Senate Bill 375 (2008), the California Air Resources Board GHG emissions reduction

targets for metropolitan planning organizations (MPOs) to achieve based on land use patterns

and transportation systems specified in Regional Transportation Plans and Sustainable

Community Strategies (RTP/SCS). Current targets for the State’s largest MPOs call for a 19

percent reduction in GHG emissions from cars and light trucks from 2005 emissions levels by

2035.

• Executive Order B-30-15 (2015) sets a GHG emissions reduction target of 40 percent below 1990

levels by 2030.

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December 2018

• Executive Order S-3-05 (2005) sets a GHG emissions reduction target of 80 percent below 1990

levels by 2050.

• Executive Order B-16-12 (2012) specifies a GHG emissions reduction target of 80 percent below

1990 levels by 2050 specifically for transportation.

• Executive Order B-55-18 (2018) established an additional statewide goal of achieving carbon

neutrality as soon as possible, but no later than 2045, and maintaining net negative emissions

thereafter. It states, “The California Air Resources Board shall work with relevant state agencies

to develop a framework for implementation and accounting that tracks progress toward this

goal.”

• Senate Bill 391 requires the California Transportation Plan to support 80 percent reduction in

GHGs below 1990 levels by 2050.

• The California Air Resources Board Mobile Source Strategy (2016) describes California’s strategy

for containing air pollutant emissions from vehicles, and quantifies VMT growth compatible with

achieving state targets.

• The California Air Resources Board’s 2017 Climate Change Scoping Plan Update: The Strategy for

Achieving California’s 2030 Greenhouse Gas Target describes California’s strategy for containing

GHG emissions from vehicles, and quantifies VMT growth compatible with achieving state

targets.

Considering these various targets, the California Supreme Court observed:

Meeting our statewide reduction goals does not preclude all new development. Rather,

the Scoping Plan … assumes continued growth and depends on increased efficiency and

conservation in land use and transportation from all Californians.

(Center for Biological Diversity v. California Dept. of Fish & Wildlife, supra, 62 Cal.4th at p. 220.) Indeed,

the Court noted that when a lead agency uses consistency with climate goals as a way to determine

significance, particularly for long-term projects, the lead agency must consider the project’s effect on

meeting long-term reduction goals. (Ibid.) And more recently, the Supreme Court stated that “CEQA

requires public agencies . . . to ensure that such analysis stay in step with evolving scientific knowledge

and state regulatory schemes.” (Cleveland National Forest Foundation v. San Diego Assn. of

Governments (2017) 3 Cal.5th 497, 504.)

Meeting the targets described above will require substantial reductions in existing VMT per capita to

curb GHG emissions and other pollutants. But targets for overall GHG emissions reduction do not

translate directly into VMT thresholds for individual projects for many reasons, including:

• Some, but not all, of the emissions reductions needed to achieve those targets could be

accomplished by other measures, including increased vehicle efficiency and decreased fuel

carbon content. The CARB’s First Update to the Climate Change Scoping Plan explains:

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December 2018

“Achieving California’s long-term criteria pollutant and GHG emissions goals will require four

strategies to be employed: (1) improve vehicle efficiency and develop zero emission

technologies, (2) reduce the carbon content of fuels and provide market support to get these

lower-carbon fuels into the marketplace, (3) plan and build communities to reduce vehicular

GHG emissions and provide more transportation options, and (4) improve the efficiency and

throughput of existing transportation systems.”

CARB’s 2018 Progress Report on California’s

Sustainable Communities and Climate Protection Act

states on page 28 that “California cannot

meet its climate goals without curbing growth in single-occupancy vehicle activity.” In other

words, vehicle efficiency and better fuels are necessary, but insufficient, to address the GHG

emissions from the transportation system. Land use patterns and transportation options also

will need to change to support reductions in vehicle travel/VMT.

• New land use projects alone will not sufficiently reduce per-capita VMT to achieve those targets,

nor are they expected to be the sole source of VMT reduction.

• Interactions between land use projects, and also between land use and transportation projects,

existing and future, together affect VMT.

• Because location within the region is the most important determinant of VMT, in some cases,

streamlining CEQA review of projects in travel efficient locations may be the most effective

means of reducing VMT.

• When assessing climate impacts of some types of land use projects, use of an efficiency metric

(e.g., per capita, per employee) may provide a better measure of impact than an absolute

numeric threshold. (Center for Biological Diversity, supra.)

Public Resources Code section 21099 directs OPR to propose criteria for determining the significance of

transportation impacts. In this Technical Advisory, OPR provides its recommendations to assist lead

agencies in selecting a significance threshold that may be appropriate for their particular projects. While

OPR’s Technical Advisory is not binding on public agencies, CEQA allows lead agencies to “consider

thresholds of significance . . . recommended by other public agencies, provided the decision to adopt

those thresholds is supported by substantial evidence.” (CEQA Guidelines, § 15064.7, subd. (c).) Based

on OPR’s extensive review of the applicable research, and in light of an assessment by the California Air

Resources Board quantifying the need for VMT reduction in order to meet the State’s long-term climate

goals, OPR recommends that a per capita or per employee VMT that is fifteen percent below that of

existing development may be a reasonable threshold.

Fifteen percent reductions in VMT are achievable at the project level in a variety of place types.

Moreover, a fifteen percent reduction is consistent with SB 743’s direction to OPR to select a threshold

that will help the State achieve its climate goals. As described above, section 21099 states that the

California Air Resources Board (May 2014) First Update to the Climate Change Scoping Plan, p. 46

(emphasis added).

CAPCOA (2010) Quantifying Greenhouse Gas Mitigation Measures, p. 55, available at

http://www.capcoa.org/wp-content/uploads/2010/11/CAPCOA-Quantification-Report-9-14-Final.pdf

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criteria for determining significance must “promote the reduction in greenhouse gas emissions.” In its

document California Air Resources Board 2017 Scoping Plan-Identified VMT Reductions and Relationship

to State Climate Goals

, CARB assesses VMT reduction per capita consistent with its evidence-based

modeling scenario that would achieve State climate goals of 40 percent GHG emissions reduction from

1990 levels by 2030 and 80 percent GHG emissions reduction levels from 1990 by 2050. Applying

California Department of Finance population forecasts, CARB finds per-capita light-duty vehicle travel

would need to be approximately 16.8 percent lower than existing, and overall per-capita vehicle travel

would need to be approximately 14.3 percent lower than existing levels under that scenario. Below

these levels, a project could be considered low VMT and would, on that metric, be consistent with 2017

Scoping Plan Update assumptions that achieve climate state climate goals.

CARB finds per capita vehicle travel would need to be kept below what today’s policies and plans would

achieve.

CARB’s assessment is based on data in the 2017 Scoping Plan Update and 2016 Mobile Source Strategy.

In those documents, CARB previously examined the relationship between VMT and the state’s GHG

emissions reduction targets. The Scoping Plan finds:

“While the State can do more to accelerate and incentivize these local decisions, local actions

that reduce VMT are also necessary to meet transportation sector-specific goals and achieve the

2030 target under SB 32. Through developing the Scoping Plan, CARB staff is more convinced

than ever that, in addition to achieving GHG reductions from cleaner fuels and vehicles,

California must also reduce VMT. Stronger SB 375 GHG reduction targets will enable the State to

make significant progress toward needed reductions, but alone will not provide the VMT growth

reductions needed; there is a gap between what SB 375 can provide and what is needed to meet

the State’s 2030 and 2050 goals.”

Note that, at present, consistency with RTP/SCSs does not necessarily lead to a less-than-significant VMT

impact.

As the Final 2017 Scoping Plan Update states,

VMT reductions are necessary to achieve the 2030 target and must be part of any strategy

evaluated in this Plan. Stronger SB 375 GHG reduction targets will enable the State to make

significant progress toward this goal, but alone will not provide all of the VMT growth reductions

that will be needed. There is a gap between what SB 375 can provide and what is needed to

meet the State’s 2030 and 2050 goals.”

California Air Resources Board (Jan. 2019) California Air Resources Board 2017 Scoping Plan-Identified

VMT Reductions and Relationship to State Climate Goals, available at

https://ww2.arb.ca.gov/resources/documents/carb-2017-scoping-plan-identified-vmt-reductions-and-

relationship-state-climate.

California Air Resources Board (Nov. 2017) California’s 2017 Climate Change Scoping Plan, p. 101.

California Air Resources Board (Feb. 2018) Updated Final Staff Report: Proposed Update to the SB 375

Greenhouse Gas Emission Reduction Targets, Figure 3, p. 35, available at

https://www.arb.ca.gov/cc/sb375/sb375_target_update_final_staff_report_feb2018.pdf

California Air Resources Board (Nov. 2017) California’s 2017 Climate Change Scoping Plan, p. 75.

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Also, in order to capture the full effects of induced travel resulting from roadway capacity projects, an

RTP/SCS would need to include an assessment of land use effects of those projects, and the effects of

those land uses on VMT. (See section titled “Estimating VMT Impacts from Transportation Projects”

below.) RTP/SCSs typically model VMT using a collaboratively-developed land use “vision” for the

region’s land use, rather than studying the effects on land use of the proposed transportation

investments.

In summary, achieving 15 percent lower per capita (residential) or per employee (office) VMT than

existing development is both generally achievable and is supported by evidence that connects this level

of reduction to the State’s emissions goals.

1. Screening Thresholds for Land Use Projects

Many agencies use “screening thresholds” to quickly identify when a project should be expected to

cause a less-than-significant impact without conducting a detailed study. (See e.g., CEQA Guidelines, §§

15063(c)(3)(C), 15128, and Appendix G.) As explained below, this technical advisory suggests that lead

agencies may screen out VMT impacts using project size, maps, transit availability, and provision of

affordable housing.

Screening Threshold for Small Projects

Many local agencies have developed screening thresholds to indicate when detailed analysis is needed.

Absent substantial evidence indicating that a project would generate a potentially significant level of

VMT, or inconsistency with a Sustainable Communities Strategy (SCS) or general plan, projects that

generate or attract fewer than 110 trips per day

generally may be assumed to cause a less-than-

significant transportation impact.

Map-Based Screening for Residential and Office Projects

Residential and office projects that locate in areas with low VMT, and that incorporate similar features

(i.e., density, mix of uses, transit accessibility), will tend to exhibit similarly low VMT. Maps created with

VMT data, for example from a travel survey or a travel demand model, can illustrate areas that are

CEQA provides a categorical exemption for existing facilities, including additions to existing structures

of up to 10,000 square feet, so long as the project is in an area where public infrastructure is available to

allow for maximum planned development and the project is not in an environmentally sensitive area.

(CEQA Guidelines, § 15301, subd. (e)(2).) Typical project types for which trip generation increases

relatively linearly with building footprint (i.e., general office building, single tenant office building, office

park, and business park) generate or attract an additional 110-124 trips per 10,000 square feet.

Therefore, absent substantial evidence otherwise, it is reasonable to conclude that the addition of 110

or fewer trips could be considered not to lead to a significant impact.

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December 2018

currently below threshold VMT (see recommendations below). Because new development in such

locations would likely result in a similar level of VMT, such maps can be used to screen out residential

and office projects from needing to prepare a detailed VMT analysis.

Figure 2. Example map of household VMT that could be used to

delineate areas eligible to receive streamlining for VMT analysis.

(Source: City of San José, Department of Transportation, draft output of

City Transportation Model.)

Presumption of Less Than Significant Impact Near Transit Stations

Proposed CEQA Guideline Section 15064.3, subdivision (b)(1), states that lead agencies generally should

presume that certain projects (including residential, retail, and office projects, as well as projects that

are a mix of these uses) proposed within ½ mile of an existing major transit stop

or an existing stop

Pub. Resources Code, § 21064.3 (“‘Major transit stop’ means a site containing an existing rail transit

station, a ferry terminal served by either a bus or rail transit service, or the intersection of two or more

major bus routes with a frequency of service interval of 15 minutes or less during the morning and

afternoon peak commute periods.”).

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December 2018

along a high quality transit corridor

will have a less-than-significant impact on VMT. This presumption

would not apply, however, if project-specific or location-specific information indicates that the project

will still generate significant levels of VMT. For example, the presumption might not be appropriate if

the project:

● Has a Floor Area Ratio (FAR) of less than 0.75

● Includes more parking for use by residents, customers, or employees of the project than

required by the jurisdiction (if the jurisdiction requires the project to supply parking)

● Is inconsistent with the applicable Sustainable Communities Strategy (as determined by the lead

agency, with input from the Metropolitan Planning Organization)

● Replaces affordable residential units with a smaller number of moderate- or high-income

residential units

A project or plan near transit which replaces affordable residential units

with a smaller number of

moderate- or high-income residential units may increase overall VMT because the increase in VMT of

displaced residents could overwhelm the improvements in travel efficiency enjoyed by new residents.

If any of these exceptions to the presumption might apply, the lead agency should conduct a detailed

VMT analysis to determine whether the project would exceed VMT thresholds (see below).

Presumption of Less Than Significant Impact for Affordable Residential Development

Adding affordable housing to infill locations generally improves jobs-housing match, in turn shortening

commutes and reducing VMT.

24,25

Further, “… low-wage workers in particular would be more likely to

choose a residential location close to their workplace, if one is available.”

In areas where existing jobs-

housing match is closer to optimal, low income housing nevertheless generates less VMT than market-

Pub. Resources Code, § 21155 (“For purposes of this section, a high-quality transit corridor means a

corridor with fixed route bus service with service intervals no longer than 15 minutes during peak

commute hours.”).

Including naturally-occurring affordable residential units.

Chapple et al. (2017) Developing a New Methodology for Analyzing Potential Displacement, Chapter 4,

pp. 159-160, available at https://www.arb.ca.gov/research/apr/past/13-310.pdf

Karner and Benner (2016) The convergence of social equity and environmental sustainability: Jobs-

housing fit and commute distance (“[P]olicies that advance a more equitable distribution of jobs and

housing by linking the affordability of locally available housing with local wage levels are likely to be

associated with reduced commuting distances”).

Karner and Benner (2015) Low-wage jobs-housing fit: identifying locations of affordable housing

shortages.

Karner and Benner (2015) Low-wage jobs-housing fit: identifying locations of affordable housing

shortages.

15 | Page

December 2018

rate housing.

27,28

Therefore, a project consisting of a high percentage of affordable housing may be a

basis for the lead agency to find a less-than-significant impact on VMT. Evidence supports a

presumption of less than significant impact for a 100 percent affordable residential development (or the

residential component of a mixed-use development) in infill locations. Lead agencies may develop their

own presumption of less than significant impact for residential projects (or residential portions of mixed

use projects) containing a particular amount of affordable housing, based on local circumstances and

evidence. Furthermore, a project which includes any affordable residential units may factor the effect

of the affordability on VMT into the assessment of VMT generated by those units.

2. Recommended Numeric Thresholds for Residential, Office, and Retail

Projects

Recommended threshold for residential projects: A proposed project exceeding a level of 15

percent below existing VMT per capita may indicate a significant transportation impact. Existing

VMT per capita may be measured as regional VMT per capita or as city VMT per capita. Proposed

development referencing a threshold based on city VMT per capita (rather than regional VMT per

capita) should not cumulatively exceed the number of units specified in the SCS for that city, and

should be consistent with the SCS.

Res

idential development that would generate vehicle travel that is 15 or more percent below the

existing residential VMT per capita, measured against the region or city, may indicate a less-than-

significant transportation impact. In MPO areas, development measured against city VMT per capita

(rather than regional VMT per capita) should not cumulatively exceed the population or number of units

specified in the SCS for that city because greater-than-planned amounts of development in areas above

the region-based threshold would undermine the VMT containment needed to achieve regional targets

under SB 375.

For residential projects in unincorporated county areas, the local agency can compare a residential

project’s VMT to (1) the region’s VMT per capita, or (2) the aggregate population-weighted VMT per

capita of all cities in the region. In MPO areas, development in unincorporated areas measured against

aggregate city VMT per capita (rather than regional VMT per capita) should not cumulatively exceed the

population or number of units specified in the SCS for that city because greater-than-planned amounts

of development in areas above the regional threshold would undermine achievement of regional targets

under SB 375.

Chapple et al. (2017) Developing a New Methodology for Analyzing Potential Displacement, available

at https://www.arb.ca.gov/research/apr/past/13-310.pdf

CAPCOA (2010) Quantifying Greenhouse Gas Mitigation Measures, pp. 176-178, available at

http://www.capcoa.org/wp-content/uploads/2010/11/CAPCOA-Quantification-Report-9-14-Final.pdf

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December 2018

These thresholds can be applied to either household (i.e., tour-based) VMT or home-based (i.e., trip-

based) VMT assessments.

It is critical, however, that the agency be consistent in its VMT measurement

approach throughout the analysis to maintain an “apples-to-apples” comparison. For example, if the

agency uses a home-based VMT for the threshold, it should also be use home-based VMT for calculating

project VMT and VMT reduction due to mitigation measures.

Because new retail development typically redistributes shopping trips rather than creating new trips,

estimating the total change in VMT (i.e., the difference in total VMT in the area affected with and

without the project) is the best way to analyze a retail project’s transportation impacts.

By adding retail opportunities into the urban fabric and thereby improving retail destination proximity,

local-serving retail development tends to shorten trips and reduce VMT. Thus, lead agencies generally

may presume such development creates a less-than-significant transportation impact. Regional-serving

retail development, on the other hand, which can lead to substitution of longer trips for shorter ones,

may tend to have a significant impact. Where such development decreases VMT, lead agencies should

consider the impact to be less-than-significant.

Many cities and counties define local-serving and regional-serving retail in their zoning codes. Lead

agencies may refer to those local definitions when available, but should also consider any project-

See Appendix 1 for a description of these approaches.

Lovejoy, et al. (2013) Measuring the impacts of local land-use policies on vehicle miles of travel:

The case of the first big-box store in Davis, California, The Journal of Transport and Land Use.

Recommended threshold for retail projects: A net increase in total VMT may indicate a significant

transportation impact.

Office pr

ojects that would generate vehicle travel exceeding 15 percent below existing VMT per

employee for the region may indicate a significant transportation impact. In cases where the region is

substantially larger than the geography over which most workers would be expected to live, it might be

appropriate to refer to a smaller geography, such as the county, that includes the area over which nearly

all workers would be expected to live.

Office VMT screening maps can be developed using tour-based data, considering either total employee

VMT or employee work tour VMT. Similarly, tour-based analysis of office project VMT could consider

either total employee VMT or employee work tour VMT. Where tour-based information is unavailable

for threshold determination, project assessment, or assessment of mitigation, home-based work trip

VMT should be used throughout all steps of the analysis to maintain an “apples-to-apples” comparison.

Recommended threshold for office projects: A proposed project exceeding a level of 15 percent

below existing regional VMT per employee may indicate a significant transportation impact.

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December 2018

specific information, such as market studies or economic impacts analyses that might bear on

customers’ travel behavior. Because lead agencies will best understand their own communities and the

likely travel behaviors of future project users, they are likely in the best position to decide when a

project will likely be local-serving. Generally, however, retail development including stores larger than

50,000 square feet might be considered regional-serving, and so lead agencies should undertake an

analysis to determine whether the project might increase or decrease VMT.

Mixed-Use Projects

Lead agencies can evaluate each component of a mixed-use project independently and apply the

significance threshold for each project type included (e.g., residential and retail). Alternatively, a lead

agency may consider only the project’s dominant use. In the analysis of each use, a project should take

credit for internal capture. Combining different land uses and applying one threshold to those land uses

may result in an inaccurate impact assessment.

Other Project Types

Of land use projects, residential, office, and retail projects tend to have the greatest influence on VMT.

For that reason, OPR recommends the quantified thresholds described above for purposes of analysis

and mitigation. Lead agencies, using more location-specific information, may develop their own more

specific thresholds, which may include other land use types. In developing thresholds for other project

types, or thresholds different from those recommended here, lead agencies should consider the

purposes described in section 21099 of the Public Resources Code and regulations in the CEQA

Guidelines on the development of thresholds of significance (e.g., CEQA Guidelines, § 15064.7).

Strategies and projects that decrease local VMT but increase total VMT should be avoided. Agencies

should consider whether their actions encourage development in a less travel-efficient location by

limiting development in travel-efficient locations.

Redevelopment Projects

Where a project replaces existing VMT-generating land uses, if the replacement leads to a net overall

decrease in VMT, the project would lead to a less-than-significant transportation impact. If the project

leads to a net overall increase in VMT, then the thresholds described above should apply.

As described above, a project or plan near transit which replaces affordable

residential units with a

smaller number of moderate- or high-income residential units may increase overall VMT, because

Including naturally-occurring affordable residential units.

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December 2018

displaced residents’ VMT may increase.

A lead agency should analyze VMT for such a project even if it

otherwise would have been presumed less than significant. The assessment should incorporate an

estimate of the aggregate VMT increase experienced by displaced residents. That additional VMT

should be included in the numerator of the VMT per capita assessed for the project.

If a residential or office project leads to a net increase in VMT, then the project’s VMT per capita

(residential) or per employee (office) should be compared to thresholds recommended above. Per

capita and per employee VMT are efficiency metrics, and, as such, apply only to the existing project

without regard to the VMT generated by the previously existing land use.

If the project leads to a net increase in provision of locally-serving retail, transportation impacts from

the retail portion of the development should be presumed to be less than significant. If the project

consists of regionally-serving retail, and increases overall VMT compared to with existing uses, then the

project would lead to a significant transportation impact.

RTP/SCS Consistency (All Land Use Projects)

Section 15125, subdivision (d), of the CEQA Guidelines provides that lead agencies should analyze

impacts resulting from inconsistencies with regional plans, including regional transportation plans. For

this reason, if a project is inconsistent with the Regional Transportation Plan and Sustainable

Communities Strategy (RTP/SCS), the lead agency should evaluate whether that inconsistency indicates

a significant impact on transportation. For example, a development may be inconsistent with an

RTP/SCS if the development is outside the footprint of development or within an area specified as open

space as shown in the SCS.

3. Recommendations Regarding Land Use Plans

As with projects, agencies should analyze VMT outcomes of land use plans across the full area over

which the plan may substantively affect travel patterns, including beyond the boundary of the plan or

jurisdiction’s geography. And as with projects, VMT should be counted in full rather than split between

origin and destination. (Emissions inventories have sometimes spit cross-boundary trips in order to sum

to a regional total, but CEQA requires accounting for the full impact without truncation or discounting).

Analysis of specific plans may employ the same thresholds described above for projects. A general plan,

area plan, or community plan may have a significant impact on transportation if proposed new

residential, office, or retail land uses would in aggregate exceed the respective thresholds

recommended above. Where the lead agency tiers from a general plan EIR pursuant to CEQA Guidelines

sections 15152 and 15166, the lead agency generally focuses on the environmental impacts that are

specific to the later project and were not analyzed as significant impacts in the prior EIR. (Pub. Resources

Code, § 21068.5; Guidelines, § 15152, subd. (a).) Thus, in analyzing the later project, the lead agency

Chapple et al. (2017) Developing a New Methodology for Analyzing Potential Displacement, Chapter 4,

pp. 159-160, available at https://www.arb.ca.gov/research/apr/past/13-310.pdf

19 | Page

December 2018

would focus on the VMT impacts that were not adequately addressed in the prior EIR. In the tiered

document, the lead agency should continue to apply the thresholds recommended above.

Thresholds for plans in non-MPO areas may be determined on a case-by-case basis.

4. Other Considerations

Rural Projects Outside of MPOs

In rural areas of non-MPO counties (i.e., areas not near established or incorporated cities or towns),

fewer options may be available for reducing VMT, and significance thresholds may be best determined

on a case-by-case basis. Note, however, that clustered small towns and small town main streets may

have substantial VMT benefits compared to isolated rural development, similar to the transit oriented

development described above.

Impacts to Transit

Because criteria for determining the significance of transportation impacts must promote “the

development of multimodal transportation networks” pursuant to Public Resources Code section 21099,

subd. (b)(1), lead agencies should consider project impacts to transit systems and bicycle and pedestrian

networks. For example, a project that blocks access to a transit stop or blocks a transit route itself may

interfere with transit functions. Lead agencies should consult with transit agencies as early as possible in

the development process, particularly for projects that are located within one half mile of transit stops.

When evaluating impacts to multimodal transportation networks, lead agencies generally should not

treat the addition of new transit users as an adverse impact. An infill development may add riders to

transit systems and the additional boarding and alighting may slow transit vehicles, but it also adds

destinations, improving proximity and accessibility. Such development also improves regional vehicle

flow by adding less vehicle travel onto the regional network.

Increased demand throughout a region may, however, cause a cumulative impact by requiring new or

additional transit infrastructure. Such impacts may be adequately addressed through a fee program that

fairly allocates the cost of improvements not just to projects that happen to locate near transit, but

rather across a region to all projects that impose burdens on the entire transportation system, since

transit can broadly improve the function of the transportation system.

F. Considering the Effects of Transportation Projects on Vehicle Travel

Many transportation projects change travel patterns. A transportation project which leads to additional

vehicle travel on the roadway network, commonly referred to as “induced vehicle travel,” would need to

quantify the amount of additional vehicle travel in order to assess air quality impacts, greenhouse gas

emissions impacts, energy impacts, and noise impacts. Transportation projects also are required to

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examine induced growth impacts under CEQA. (See generally, Pub. Resources Code, §§ 21065 [defining

“project” under CEQA as an activity as causing either a direct or reasonably foreseeable indirect physical

change], 21065.3 [defining “project-specific effect” to mean all direct or indirect environmental effects],

21100, subd. (b) [required contents of an EIR].) For any project that increases vehicle travel, explicit

assessment and quantitative reporting of the amount of additional vehicle travel should not be omitted

from the document; such information may be useful and necessary for a full understanding of a project’s

environmental impacts. (See Pub. Resources Code, §§ 21000, 21001, 21001.1, 21002, 21002.1

[discussing the policies of CEQA].) A lead agency that uses the VMT metric to assess the transportation

impacts of a transportation project may simply report that change in VMT as the impact. When the lead

agency uses another metric to analyze the transportation impacts of a roadway project, changes in

amount of vehicle travel added to the roadway network should still be analyzed and reported.

While CEQA does not require perfection, it is important to make a reasonably accurate estimate of

transportation projects’ effects on vehicle travel in order to make reasonably accurate estimates of GHG

emissions, air quality emissions, energy impacts, and noise impacts. (See, e.g., California Clean Energy

Com. v. City of Woodland (2014) 225 Cal.App.4th 173, 210 [EIR failed to consider project’s

transportation energy impacts]; Ukiah Citizens for Safety First v. City of Ukiah (2016) 248 Cal.App.4th

256, 266.) Appendix 2 describes in detail the causes of induced vehicle travel, the robust empirical

evidence of induced vehicle travel, and how models and research can be used in conjunction to

quantitatively assess induced vehicle travel with reasonable accuracy.

If a project would likely lead to a measurable and substantial increase in vehicle travel, the lead agency

should conduct an analysis assessing the amount of vehicle travel the project will induce. Project types

that would likely lead to a measurable and substantial increase in vehicle travel generally include:

• Addition of through lanes on existing or new highways, including general purpose lanes, HOV

lanes, peak period lanes, auxiliary lanes, or lanes through grade-separated interchanges

Projects that would not likely lead to a substantial or measurable increase in vehicle travel, and

therefore generally should not require an induced travel analysis, include:

• Rehabilitation, maintenance, replacement, safety, and repair projects designed to improve the

condition of existing transportation assets (e.g., highways; roadways; bridges; culverts;

Transportation Management System field elements such as cameras, message signs, detection,

or signals; tunnels; transit systems; and assets that serve bicycle and pedestrian facilities) and

that do not add additional motor vehicle capacity

• Roadside safety devices or hardware installation such as median barriers and guardrails

See, e.g., California Department of Transportation (2006) Guidance for Preparers of Growth-related,

Indirect Impact Analyses, available at

http://www.dot.ca.gov/ser/Growth-

related_IndirectImpactAnalysis/GRI_guidance06May_files/gri_guidance.pdf.

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• Roadway shoulder enhancements to provide “breakdown space,” dedicated space for use only

by transit vehicles, to provide bicycle access, or to otherwise improve safety, but which will not

be used as automobile vehicle travel lanes

• Addition of an auxiliary lane of less than one mile in length designed to improve roadway safety

• Installation, removal, or reconfiguration of traffic lanes that are not for through traffic, such as

left, right, and U-turn pockets, two-way left turn lanes, or emergency breakdown lanes that are

not utilized as through lanes

• Addition of roadway capacity on local or collector streets provided the project also substantially

improves conditions for pedestrians, cyclists, and, if applicable, transit

• Conversion of existing general purpose lanes (including ramps) to managed lanes or transit

lanes, or changing lane management in a manner that would not substantially increase vehicle

travel

• Addition of a new lane that is permanently restricted to use only by transit vehicles

• Reduction in number of through lanes

• Grade separation to separate vehicles from rail, transit, pedestrians or bicycles, or to replace a

lane in order to separate preferential vehicles (e.g., HOV, HOT, or trucks) from general vehicles

• Installation, removal, or reconfiguration of traffic control devices, including Transit Signal

Priority (TSP) features

• Installation of traffic metering systems, detection systems, cameras, changeable message signs

and other electronics designed to optimize vehicle, bicycle, or pedestrian flow

• Timing of signals to optimize vehicle, bicycle, or pedestrian flow

• Installation of roundabouts or traffic circles

• Installation or reconfiguration of traffic calming devices

• Adoption of or increase in tolls

• Addition of tolled lanes, where tolls are sufficient to mitigate VMT increase

• Initiation of new transit service

• Conversion of streets from one-way to two-way operation with no net increase in number of

traffic lanes

• Removal or relocation of off-street or on-street parking spaces

• Adoption or modification of on-street parking or loading restrictions (including meters, time

limits, accessible spaces, and preferential/reserved parking permit programs)

• Addition of traffic wayfinding signage

• Rehabilitation and maintenance projects that do not add motor vehicle capacity

• Addition of new or enhanced bike or pedestrian facilities on existing streets/highways or within

existing public rights-of-way

• Addition of Class I bike paths, trails, multi-use paths, or other off-road facilities that serve non-

motorized travel

• Installation of publicly available alternative fuel/charging infrastructure

• Addition of passing lanes, truck climbing lanes, or truck brake-check lanes in rural areas that do

not increase overall vehicle capacity along the corridor

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1. Recommended Significance Threshold for Transportation Projects

As noted in Section 15064.3 of the CEQA Guidelines, lead agencies for roadway capacity projects have

discretion, consistent with CEQA and planning requirements, to choose which metric to use to evaluate

transportation impacts. This section recommends considerations for evaluating impacts using vehicle

miles traveled. Lead agencies have discretion to choose a threshold of significance for transportation

projects as they do for other types of projects. As explained above, Public Resources Code section

21099, subdivision (b)(1), provides that criteria for determining the significance of transportation

impacts must promote the reduction of greenhouse gas emissions, the development of multimodal

transportation networks, and a diversity of land uses. (Id.; see generally, adopted CEQA Guidelines, §

15064.3, subd. (b) [Criteria for Analyzing Transportation Impacts].) With those goals in mind, OPR

prepared and the Agency adopted an appropriate transportation metric.

Whether adopting a threshold of significance, or evaluating transportation impacts on a case-by-case

basis, a lead agency should ensure that the analysis addresses:

• Direct, indirect and cumulative effects of the transportation project (CEQA Guidelines, § 15064,

subds. (d), (h))

• Near-term and long-term effects of the transportation project (CEQA Guidelines, §§ 15063,

subd. (a)(1), 15126.2, subd. (a))

• The transportation project’s consistency with state greenhouse gas reduction goals (Pub.

Resources Code, § 21099)

• The impact of the transportation project on the development of multimodal transportation

networks (Pub. Resources Code, § 21099)

• The impact of the transportation project on the development of a diversity of land uses (Pub.

Resources Code, § 21099)

The CARB Scoping Plan and the CARB Mobile Source Strategy delineate VMT levels required to achieve

legally mandated GHG emissions reduction targets. A lead agency should develop a project-level

threshold based on those VMT levels, and may apply the following approach:

1. Propose a fair-share allocation of those budgets to their jurisdiction (e.g., by population);

The California Air Resources Board has ascertained the limits of VMT growth compatible with

California containing greenhouse gas emissions to levels research shows would allow for climate

stabilization. (See

The 2017 Climate Change Scoping Plan: The Strategy for Achieving California’s 2030

Greenhouse Gas Target (p. 78, p. 101); Mobile Source Strategy (p. 37).) CARB’s Updated Final Staff

Report on Proposed Update to the SB 375 Greenhouse Gas Emission Reduction Targets illustrates that

the current Regional Transportation Plans and Sustainable Communities Strategies will fall short of

achieving the necessary on-road transportation-related GHG emissions reductions called for in the 2017

Scoping Plan (Figure 3, p. 35). Accordingly, OPR recommends not basing GHG emissions or

transportation impact analysis for a transportation project solely on consistency with an RTP/SCS.

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2. Determine the amount of VMT growth likely to result from background population growth, and

subtract that from their “budget”;

3. Allocate their jurisdiction’s share between their various VMT-increasing transportation projects,

using whatever criteria the lead agency prefers.

2. Estimating VMT Impacts from Transportation Projects

CEQA requires analysis of a project’s potential growth-inducing impacts. (Pub. Resources Code, § 21100,

subd. (b)(5); CEQA Guidelines, § 15126.2, subd. (d).) Many agencies are familiar with the analysis of

growth inducing impacts associated with water, sewer, and other infrastructure. This technical advisory

addresses growth that may be expected from roadway expansion projects.

Because a roadway expansion project can induce substantial VMT, incorporating quantitative estimates

of induced VMT is critical to calculating both transportation and other impacts of these projects.

Induced travel also has the potential to reduce or eliminate congestion relief benefits. An accurate

estimate of induced travel is needed to accurately weigh costs and benefits of a highway capacity

expansion project.

The effect of a transportation project on vehicle travel should be estimated using the “change in total

VMT” method described in Appendix 1. This means that an assessment of total VMT without the project

and an assessment with the project should be made; the difference between the two is the amount of

VMT attributable to the project. The assessment should cover the full area in which driving patterns are

expected to change. As with other types of projects, the VMT estimation should not be truncated at a

modeling or jurisdictional boundary for convenience of analysis when travel behavior is substantially

affected beyond that boundary.

Transit and Active Transportation Projects

Transit and active transportation projects generally reduce VMT and therefore are presumed to cause a

less-than-significant impact on transportation. This presumption may apply to all passenger rail projects,

bus and bus rapid transit projects, and bicycle and pedestrian infrastructure projects. Streamlining

transit and active transportation projects aligns with each of the three statutory goals contained in SB

743 by reducing GHG emissions, increasing multimodal transportation networks, and facilitating mixed

use development.

Roadway Projects

Reducing roadway capacity (for example, by removing or repurposing motor vehicle travel lanes) will

generally reduce VMT and therefore is presumed to cause a less-than-significant impact on

transportation. Generally, no transportation analysis is needed for such projects.

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Building new roadways, adding roadway capacity in congested areas, or adding roadway capacity to

areas where congestion is expected in the future, typically induces additional vehicle travel. For the

types of projects previously indicated as likely to lead to additional vehicle travel, an estimate should be

made of the change in vehicle travel resulting from the project.

For projects that increase roadway capacity, lead agencies can evaluate induced travel quantitatively by

applying the results of existing studies that examine the magnitude of the increase of VMT resulting

from a given increase in lane miles. These studies estimate the percent change in VMT for every percent

change in miles to the roadway system (i.e., “elasticity”).

Given that lead agencies have discretion in

choosing their methodology, and the studies on induced travel reveal a range of elasticities, lead

agencies may appropriately apply professional judgment in studying the transportation effects of a

particular project. The most recent major study, estimates an elasticity of 1.0, meaning that every

percent change in lane miles results in a one percent increase in VMT.

To estimate VMT impacts from roadway expansion projects:

1. Dete

rmine the total lane-miles over an area that fully captures travel behavior changes

resulting from the project (generally the region, but for projects affecting interregional travel

look at all affected regions).

2. Determine the percent change in total lane miles that will result from the project.

3. Determine the total existing VMT over that same area.

4. Multiply the percent increase in lane miles by the existing VMT, and then multiply that by the

elasticity from the induced travel literature:

[% increase in lane miles] x [existing VMT] x [elasticity] = [VMT resulting from the project]

A National Center for Sustainable Transportation tool can be used to apply this method:

https://ncst.ucdavis.edu/research/tools

This me

thod would not be suitable for rural (non-MPO) locations in the state which are neither

congested nor projected to become congested. It also may not be suitable for a new road that provides

new connectivity across a barrier (e.g., a bridge across a river) if it would be expected to substantially

See U.C. Davis, Institute for Transportation Studies (Oct. 2015) Increasing Highway Capacity Unlikely

to Relieve Traffic Congestion; Boarnet and Handy (Sept. 2014) Impact of Highway Capacity and Induced

Travel on Passenger Vehicle Use and Greenhouse Gas Emissions, California Air Resources Board Policy

Brief, available at https://www.arb.ca.gov/cc/sb375/policies/hwycapacity/highway_capacity_brief.pdf

See Duranton and Turner (2011) The Fundamental Law of Road Congestion: Evidence from US cities,

available at http://www.nber.org/papers/w15376

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shorten existing trips. If it is likely to be substantial, the trips-shortening effect should be examined

explicitly.

The effects of roadway capacity on vehicle travel can also be applied at a programmatic level. For

example, in a regional planning process the lead agency can use that program-level analysis to

streamline later project-level analysis. (See CEQA Guidelines, § 15168.) A program-level analysis of VMT

should include effects of the program on land use patterns, and the VMT that results from those land

use effects. In order for a program-level document to adequately analyze potential induced demand

from a project or program of roadway capacity expansion, lead agencies cannot assume a fixed land use

pattern (i.e., a land use pattern that does not vary in response to the provision of roadway capacity). A

proper analysis should account for land use investment and development pattern changes that react in a

reasonable manner to changes in accessibility created by transportation infrastructure investments

(whether at the project or program level).

Mitigation and Alternatives

Induced VMT has the potential to reduce or eliminate congestion relief benefits, increase VMT, and

increase other environmental impacts that result from vehicle travel.

If those effects are significant,

the lead agency will need to consider mitigation or alternatives. In the context of increased travel that is

induced by capacity increases, appropriate mitigation and alternatives that a lead agency might consider

include the following:

• Tolling new lanes to encourage carpools and fund transit improvements

• Converting existing general purpose lanes to HOV or HOT lanes

• Implementing or funding off-site travel demand management

• Implementing Intelligent Transportation Systems (ITS) strategies to improve passenger

throughput on existing lanes

Tolling and other management strategies can have the additional benefit of preventing congestion and

maintaining free-flow conditions, conferring substantial benefits to road users as discussed above.

G. Analyzing Other Impacts Related to Transportation

While requiring a change in the methodology of assessing transportation impacts, Public Resources

Code section 21099 notes that this change “does not relieve a public agency of the requirement to

analyze a project’s potentially significant transportation impacts related to air quality, noise, safety, or

any other impact associated with transportation.” OPR expects that lead agencies will continue to

See National Center for Sustainable Transportation (Oct. 2015) Increasing Highway Capacity Unlikely

to Relieve Traffic Congestion, available at

http://www.dot.ca.gov/newtech/researchreports/reports/2015/10-12-2015-

NCST_Brief_InducedTravel_CS6_v3.pdf; see Duranton and Turner (2011) The Fundamental Law of Road

Congestion: Evidence from US cities, available at http://www.nber.org/papers/w15376.

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address mobile source emissions in the air quality and noise sections of an environmental document and

the corresponding studies that support the analysis in those sections. Lead agencies should continue to

address environmental impacts of a proposed project pursuant to CEQA’s requirements, using a format

that is appropriate for their particular project.

Because safety concerns result from many different factors, they are best addressed at a programmatic

level (i.e., in a general plan or regional transportation plan) in cooperation with local governments,

metropolitan planning organizations, and, where the state highway system is involved, the California

Department of Transportation. In most cases, such an analysis would not be appropriate on a project-

by-project basis. Increases in traffic volumes at a particular location resulting from a project typically

cannot be estimated with sufficient accuracy or precision to provide useful information for an analysis of

safety concerns. Moreover, an array of factors affect travel demand (e.g., strength of the local economy,

price of gasoline), causing substantial additional uncertainty. Appendix B of OPR’s

General Plan

Guidelines summarizes research which could be used to guide a programmatic analysis under CEQA.

Lead agencies should note that automobile congestion or delay does not constitute a significant

environmental impact (Pub. Resources Code, §21099(b)(2)), and safety should not be used as a proxy for

road capacity.

H. VMT Mitigation and Alternatives

When a lead agency identifies a significant impact, it must identify feasible mitigation measures that

could avoid or substantially reduce that impact. (Pub. Resources Code, § 21002.1, subd. (a).)

Additionally, CEQA requires that an environmental impact report identify feasible alternatives that could

avoid or substantially reduce a project’s significant environmental impacts.

Indeed, the California Court of Appeal recently held that a long-term regional transportation plan was

deficient for failing to discuss an alternative which could significantly reduce total vehicle miles traveled.

In Cleveland National Forest Foundation v. San Diego Association of Governments, et al. (2017) 17

Cal.App.5th 413, the court found that omission “inexplicable” given the lead agency’s “acknowledgment

in its Climate Action Strategy that the state’s efforts to reduce greenhouse gas emissions from on-road

transportation will not succeed if the amount of driving, or vehicle miles traveled, is not significantly

reduced.” (Cleveland National Forest Foundation, supra, 17 Cal.App.5th at p. 436.) Additionally, the

court noted that the project alternatives focused primarily on congestion relief even though “the

[regional] transportation plan is a long-term and congestion relief is not necessarily an effective long-

term strategy.” (Id. at p. 437.) The court concluded its discussion of the alternatives analysis by stating:

“Given the acknowledged long-term drawbacks of congestion relief alternatives, there is not substantial

evidence to support the EIR’s exclusion of an alternative focused primarily on significantly reducing

vehicle trips.” (Ibid.)

Several examples of potential mitigation measures and alternatives to reduce VMT are described below.

However, the selection of particular mitigation measures and alternatives are left to the discretion of

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the lead agency, and mitigation measures may vary, depending on the proposed project and significant

impacts, if any. Further, OPR expects that agencies will continue to innovate and find new ways to

reduce vehicular travel.

Potential measures to reduce vehicle miles traveled include, but are not limited to:

• Improve or increase access to transit.

• Increase access to common goods and services, such as groceries, schools, and daycare.

• Incorporate affordable housing into the project.

• Incorporate neighborhood electric vehicle network.

• Orient the project toward transit, bicycle and pedestrian facilities.

• Improve pedestrian or bicycle networks, or transit service.

• Provide traffic calming.

• Provide bicycle parking.

• Limit or eliminate parking supply.

• Unbundle parking costs.

• Provide parking cash-out programs.

• Implement roadway pricing.

• Implement or provide access to a commute reduction program.

• Provide car-sharing, bike sharing, and ride-sharing programs.

• Provide transit passes.

• Shifting single occupancy vehicle trips to carpooling or vanpooling, for example providing ride-

matching services.

• Providing telework options.

• Providing incentives or subsidies that increase the use of modes other than single-occupancy

vehicle.

• Providing on-site amenities at places of work, such as priority parking for carpools and vanpools,

secure bike parking, and showers and locker rooms.

• Providing employee transportation coordinators at employment sites.

• Providing a guaranteed ride home service to users of non-auto modes.

Notably, because VMT is largely a regional impact, regional VMT-reduction programs may be an

appropriate form of mitigation. In lieu fees have been found to be valid mitigation where there is both a

commitment to pay fees and evidence that mitigation will actually occur. (Save Our Peninsula

Committee v. Monterey County Bd. of Supervisors (2001) 87 Cal.App.4th 99, 140-141; Gentry v. City of

Murrieta (1995) 36 Cal.App.4th 1359; Kings County Farm Bureau v. City of Hanford (1990) 221

Cal.App.3d 692, 727–728.) Fee programs are particularly useful to address cumulative impacts. (CEQA

Guidelines, § 15130, subd. (a)(3) [a “project’s incremental contribution is less than cumulatively

considerable if the project is required to implement or fund its fair share of a mitigation measure or

measures designed to alleviate the cumulative impact”].) The mitigation program must undergo CEQA

evaluation, either on the program as a whole, or the in-lieu fees or other mitigation must be evaluated

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on a project-specific basis. (California Native Plant Society v. County of El Dorado (2009) 170 Cal.App.4th

1026.) That CEQA evaluation could be part of a larger program, such as a regional transportation plan,

analyzed in a Program EIR. (CEQA Guidelines, § 15168.)

Examples of project alternatives that may reduce vehicle miles traveled include, but are not limited to:

• Locate the project in an area of the region that already exhibits low VMT.

• Locate the project near transit.

• Increase project density.

• Increase the mix of uses within the project or within the project’s surroundings.

• Increase connectivity and/or intersection density on the project site.

• Deploy management strategies (e.g., pricing, vehicle occupancy requirements) on roadways or

roadway lanes.

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Appendix 1. Considerations About Which VMT to Count

Consistent with the obligation to make a good faith effort to disclose the environmental consequences

of a project, lead agencies have discretion to choose the most appropriate methodology to evaluate

project impacts.

A lead agency can evaluate a project’s effect on VMT in numerous ways. The purpose

of this document is to provide technical considerations in determining which methodology may be most

useful for various project types.

Background on Estimating Vehicle Miles Traveled

Before discussing specific methodological recommendations, this section provides a brief overview of

modeling and counting VMT, including some key terminology.

Here is an illustrative example of some methods of estimating vehicle miles traveled. Consider the

following hypothetical travel day (all by automobile):

1. Residence to Coffee Shop

2. Coffee Shop to Work

3. Work to Sandwich Shop

4. Sandwich Shop to Work

5. Work to Residence

6. Residence to Store

7. Store to Residence

Trip-based assessment of a project’s effect on travel behavior counts VMT from individual trips to and

from the project. It is the most basic, and traditionally the most common, method of counting VMT. A

trip-based VMT assessment of the residence in the above example would consider segments 1, 5, 6 and

7. For residential projects, the sum of home-based trips is called home-based VMT.

A tour-based assessment counts the entire home-back-to-home tour that includes the project. A tour-

based VMT assessment of the residence in the above example would consider segments 1, 2, 3, 4, and 5

in one tour, and 6 and 7 in a second tour. A tour-based assessment of the workplace would include

segments 1, 2, 3, 4, and 5. Together, all tours comprise household VMT.

The California Supreme Court has explained that when an agency has prepared an environmental

impact report:

[T]he issue is not whether the [lead agency’s] studies are irrefutable or whether they

could have been better. The relevant issue is only whether the studies are sufficiently

credible to be considered as part of the total evidence that supports the [lead agency’s]

finding[.]

(Laurel Heights Improvement Assn. v. Regents of the University of California (1988) 47 Cal.3d 376, 409;

see also Eureka Citizens for Responsible Gov’t v. City of Eureka (2007) 147 Cal.App.4th 357, 372.)

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Both trip- and tour-based assessments can be used as measures of transportation efficiency, using

denominators such as per capita, per employee, or per person-trip.

Trip- and Tour-based Assessment of VMT

As illustrated above, a tour-based assessment of VMT is a more complete characterization of a project’s

effect on VMT. In many cases, a project affects travel behavior beyond the first destination. The location

and characteristics of the home and workplace will often be the main drivers of VMT. For example, a

residential or office development located near high quality transit will likely lead to some commute trips

utilizing transit, affecting mode choice on the rest of the tour.

Characteristics of an office project can also affect an employee’s VMT beyond the work tour. For

example, a workplace located at the urban periphery, far from transit, can require an employee to own

a car, which in turn affects the entirety of an employee’s travel behavior and VMT. For this reason, when

estimating the effect of an office development on VMT, it may be appropriate to consider total

employee VMT if data and tools, such as tour-based models, are available. This is consistent with CEQA’s

requirement to evaluate both direct and indirect effects of a project. (See CEQA Guidelines, § 15064,

subd. (d)(2).)

Assessing Change in Total VMT

A third method, estimating the change in total VMT with and without the project, can evaluate whether

a project is likely to divert existing trips, and what the effect of those diversions will be on total VMT.

This method answers the question, “What is the net effect of the project on area VMT?” As an

illustration, assessing the total change in VMT for a grocery store built in a food desert that diverts trips

from more distant stores could reveal a net VMT reduction. The analysis should address the full area

over which the project affects travel behavior, even if the effect on travel behavior crosses political

boundaries.

Using Models to Estimate VMT

Travel demand models, sketch models, spreadsheet models, research, and data can all be used to

calculate and estimate VMT (see Appendix F of the preliminary discussion draft

). To the extent possible,

lead agencies should choose models that have sensitivity to features of the project that affect VMT.

Those tools and resources can also assist in establishing thresholds of significance and estimating VMT

reduction attributable to mitigation measures and project alternatives. When using models and tools for

those various purposes, agencies should use comparable data and methods, in order to set up an

“apples-to-apples” comparison between thresholds, VMT estimates, and VMT mitigation estimates.

Models can work together. For example, agencies can use travel demand models or survey data to

estimate existing trip lengths and input those into sketch models such as CalEEMod to achieve more

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accurate results. Whenever possible, agencies should input localized trip lengths into a sketch model to

tailor the analysis to the project location. However, in doing so, agencies should be careful to avoid

double counting if the sketch model includes other inputs or toggles that are proxies for trip length (e.g.,

distance to city center). Generally, if an agency changes any sketch model defaults, it should record and

report those changes for transparency of analysis. Again, trip length data should come from the same

source as data used to calculate thresholds to be sure of an “apples-to-apples” comparison.

Additional background information regarding travel demand models is available in the California

Transportation Commission’s “2010 Regional Transportation Plan Guidelines

,” beginning at page 35.

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Appendix 2. Induced Travel: Mechanisms, Research, and Additional Assessment Approaches

Induced travel occurs where roadway capacity is expanded in an area of present or projected future

congestion. The effect typically manifests over several years. Lower travel times make the modified

facility more attractive to travelers, resulting in the following trip-making changes:

● Longer trips. The ability to travel a long distance in a shorter time increases the attractiveness of

destinations that are farther away, increasing trip length and vehicle travel.

● Changes in mode choice. When transportation investments are devoted to reducing automobile

travel time, travelers tend to shift toward automobile use from other modes, which increases

vehicle travel.

● Route changes. Faster travel times on a route attract more drivers to that route from other

routes, which can increase or decrease vehicle travel depending on whether it shortens or

lengthens trips.

● Newly generated trips. Increasing travel speeds can induce additional trips, which increases

vehicle travel. For example, an individual who previously telecommuted or purchased goods on

the internet might choose to accomplish those tasks via automobile trips as a result of increased

speeds.

● Land Use Changes. Faster travel times along a corridor lead to land development farther along

that corridor; that new development generates and attracts longer trips, which increases vehicle

travel. Over several years, this induced growth component of induced vehicle travel can be

substantial, making it critical to include in analyses.

Each of these effects has implications for the total amount of vehicle travel. These effects operate over

different time scales. For example, changes in mode choice might occur immediately, while land use

changes typically take a few years or longer. CEQA requires lead agencies to analyze both short-term

and long-term effects.

Evidence of Induced Vehicle Travel. A large number of peer reviewed studies

have demonstrated a

causal link between highway capacity increases and VMT increases. Many provide quantitative

estimates of the magnitude of the induced VMT phenomenon. Collectively, they provide high quality

evidence of the existence and magnitude of the induced travel effect.

See, e.g., Boarnet and Handy (Sept. 2014) Impact of Highway Capacity and Induced Travel on

Passenger Vehicle Use and Greenhouse Gas Emissions, California Air Resources Board Policy Brief,

available at https://www.arb.ca.gov/cc/sb375/policies/hwycapacity/highway_capacity_brief.pdf

;

National Center for Sustainable Transportation (Oct. 2015) Increasing Highway Capacity Unlikely to

Relieve Traffic Congestion, available at

http://www.dot.ca.gov/research/researchreports/reports/2015/10-12-2015-

NCST_Brief_InducedTravel_CS6_v3.pdf.

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Most of these studies express the amount of induced vehicle travel as an “elasticity,” which is a

multiplier that describes the additional vehicle travel resulting from an additional lane mile of roadway

capacity added. For example, an elasticity of 0.6 would signify an 0.6 percent increase in vehicle travel

for every 1.0 percent increase in lane miles. Many of these studies distinguish “short run elasticity”

(increase in vehicle travel in the first few years) from “long run elasticity” (increase in vehicle travel

beyond the first few years). Long run elasticity is larger than short run elasticity, because as time passes,

more of the components of induced vehicle travel materialize. Generally, short run elasticity can be

thought of as excluding the effects of land use change, while long run elasticity includes them. Most

studies find a long run elasticity between 0.6 and just over 1.0,

meaning that every increase in lanes

miles of one percent leads to an increase in vehicle travel of 0.6 to 1.0 percent. The most recent major

study finds the elasticity of vehicle travel by lanes miles added to be 1.03; in other words, each percent

increase in lane miles results in a 1.03 percent increase in vehicle travel.

(An elasticity greater than 1.0

can occur because new lanes induce vehicle travel that spills beyond the project location.) In CEQA

analysis, the long-run elasticity should be used, as it captures the full effect of the project rather than

just the early-stage effect.

Quantifying Induced Vehicle Travel Using Models. Lead agencies can generally achieve the most accurate

assessment of induced vehicle travel resulting from roadway capacity increasing projects by applying

elasticities from the academic literature, because those estimates include vehicle travel resulting from

induced land use. If a lead agency chooses to use a travel demand model, additional analysis would be

needed to account for induced land use. This section describes some approaches to undertaking that

additional analysis.

Proper use of a travel demand model can capture the following components of induced VMT:

• Trip length (generally increases VMT)

• Mode shift (generally shifts from other modes toward automobile use, increasing VMT)

• Route changes (can act to increase or decrease VMT)

• Newly generated trips (generally increases VMT)

o Note that not all travel demand models have sensitivity to this factor, so an off-model

estimate may be necessary if this effect could be substantial.

However, estimating long-run induced VMT also requires an estimate of the project’s effects on land

use. This component of the analysis is important because it has the potential to be a large component of

See Boarnet and Handy (Sept. 2014) Impact of Highway Capacity and Induced Travel on Passenger

Vehicle Use and Greenhouse Gas Emissions, California Air Resources Board Policy Brief, p. 2, available at

https://www.arb.ca.gov/cc/sb375/policies/hwycapacity/highway_capacity_brief.pdf.

Duranton and Turner (2011) The Fundamental Law of Road Congestion: Evidence from US cities,

available at http://www.nber.org/papers/w15376

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the overall induced travel effect. Options for estimating and incorporating the VMT effects that are

caused by the subsequent land use changes include:

1. Employ an expert panel. An expert panel could assess changes to land use development that

would likely result from the project. This assessment could then be analyzed by the travel

demand model to assess effects on vehicle travel. Induced vehicle travel assessed via this

approach should be verified using elasticities found in the academic literature.

2. Adjust model results to align with the empirical research. If the travel demand model analysis is

performed without incorporating projected land use changes resulting from the project, the

assessed vehicle travel should be adjusted upward to account for those land use changes. The

assessed VMT after adjustment should fall within the range found in the academic literature.

3. Employ a land use model, running it iteratively with a travel demand model. A land use model

can be used to estimate the land use effects of a roadway capacity increase, and the traffic

patterns that result from the land use change can then be fed back into the travel demand

model. The land use model and travel demand model can be iterated to produce an accurate

result.

A project which provides new connectivity across a barrier, such as a new bridge across a river, may

provide a shortened path between existing origins and destinations, thereby shortening existing trips. In

rare cases, this trip-shortening effect might be substantial enough to reduce the amount of vehicle

travel resulting from the project below the range found in the elasticities in the academic literature, or

even lead a net reduction in vehicle travel overall. In such cases, the trip-shortening effect could be

examined explicitly.

Whenever employing a travel demand model to assess induced vehicle travel, any limitation or known

lack of sensitivity in the analysis that might cause substantial errors in the VMT estimate (for example,

model insensitivity to one of the components of induced VMT described above) should be disclosed and

characterized, and a description should be provided on how it could influence the analysis results. A

discussion of the potential error or bias should be carried into analyses that rely on the VMT analysis,

such as greenhouse gas emissions, air quality, energy, and noise.