Vehicle Miles Traveled Replaces Level of Service

December 1, 2019

Photo Credit: Benjamin Massello via Unsplash

Public Agency Update: The time is approaching for agencies to change how they measure CEQA transportation impacts. For land use projects, beginning July 1, 2020, transportation impacts must be measured using vehicle miles traveled (VMT) instead of level of service (LOS). This article explains when public agencies may use each method moving forward.

Beginning July 1, 2020, the only acceptable ways of determining the significance of transportation impacts in California Environmental Quality Act (CEQA) environmental review documents are the methods listed in CEQA Guidelines Section 15064.3 (see also Public Resources Code Section 21099). CEQA Guidelines Appendix G (Section XVII.b) has also been amended to make this updated approach clear. This change in the law means that transportation impacts must be measured by the increase in Vehicle Miles Traveled (VMT) for most – but not all – new projects.

The switch to a VMT metric began in 2013, with the enactment of Senate Bill 743. In SB 743, the Legislature declared “its commitment to encouraging land use and transportation planning decisions and investments that reduce vehicle miles traveled and contribute to reductions in greenhouse gas emissions…” SB 743 directed the Governor’s Office of Planning and Research (OPR) to develop an alternative process to the commonly used Level of Service (LOS) analysis for analyzing transportation impacts under CEQA. In December 2018, the California Natural Resources Agency certified OPR’s proposed changes to the CEQA Guidelines, which identify VMT as the most appropriate metric to measure transportation impacts.

Moving to a VMT standard involves a complete change in how the transportation impacts of land use and transportation projects are framed. Up until this point, most agencies have used LOS, which measures the capacity of roadways to accommodate traffic.

The Difference Between VMT and LOS

Prior to the recent amendments, the CEQA Guidelines were interpreted to require agencies to consider the transportation impacts of proposed projects by the amount of automobile delay caused. The LOS standard was commonly used to assess such delay. LOS measures the capacity of street intersections, highway interchanges, and roadway segments to accommodate traffic in terms of the delay caused by additional traffic. The VMT metric provides a more complete description of environmental impacts than the LOS standard, however, because it measures the door-to-door greenhouse gas impacts generated by drivers using the proposed projects. VMT thus considers the total transportation impacts of a new project from when users get into a car to when they return to their point of origin.

In order to reduce transportation impacts as measured by VMT, an agency needs to decrease the total number of vehicle miles traveled. Methods for decreasing VMT include: providing transportation alternatives, implementing pricing strategies, developing in a way that increases transportation efficiencies, investing in transportation banking, and focusing on infill development. Under the LOS metric, an agency could increase service levels simply by widening a road. While wider roads might temporarily decrease automobile delay, this approach does not ultimately decrease greenhouse gas pollution.

When Must VMT Be Used?

Moving forward, the acceptable methods for analyzing transportation impacts under Section 15064.3(b), are as follows:

For land use projects, the measure of transportation impacts will only be VMT. But in the following circumstances, land use projects are presumed to cause a less than significant transportation impact. These presumptions are rebuttable, according to the California Natural Resources Agency.
Land use projects within one-half mile of an existing (i) “major transit stop” (as defined in Public Resources Codeº 21064.3) or (ii) “high quality transit corridor” (as defined in Public Resources Codeº 21155(b)) should be presumed to cause a less than significant transportation impact; and
Land use projects that decrease VMT should also be presumed to cause a less than significant transportation impact.

For these types of projects, no transportation analysis for impacts due to vehicular traffic will normally be required.

For transportation projects, unlike land use projects, agencies may continue to use LOS analysis in some circumstances.
Transportation projects that reduce or have no impact on VMT should be presumed to cause a less than significant transportation impact. Again, this presumption is rebuttable.
For “roadway capacity projects,” unlike land use projects, public agencies have the discretion to determine the appropriate measure of transportation impacts, and may continue to use LOS.
In addition, agencies may tier environmental review from a regional transportation plan environmental impact report (EIR) or other programmatic level EIR, regardless of the method used to analyze transportation impacts in those documents.

What Does VMT Analysis Actually Involve?

In practice, VMT modeling may not pose an extra burden. Even before the recent CEQA Guidelines amendments, calculating a project’s effects on VMT often was part of the environmental review process. That is because VMT is a better measure than LOS for modeling a project’s greenhouse gas, air quality, and energy impacts. VMT studies also are expected to be considerably less costly than LOS studies, because the VMT metric does not require simulating all project-impacted intersections.

In addition, public agencies retain some flexibility under Section 15064.3 to choose how to evaluate a project’s change on VMT. An agency may use a qualitative approach based on factors such as availability of transit and proximity to other destinations if models and other quantitative methods are not available. This approach will likely be widely used in the early years of VMT analysis until agencies establish numerical thresholds.

The Guidelines also allow agencies to exercise judgment on modeling assumptions and outputs as long as the choice of methodology is documented and based on substantial evidence.

VMT Thresholds of Significance

Agencies have options for selecting the appropriate VMT thresholds of significance. Section 15064.3(b)(4) provides the following acceptable measures: absolute number of vehicle miles traveled, VMT per capita, VMT per household, VMT per employee, “or any other measure.” The CEQA Guidelines do not establish a threshold of significance, however. To assist agencies, OPR recommends “a per capita or employee VMT that is fifteen percent below that of existing development” as a “reasonable threshold.” (OPR Technical Advisory Report: On Evaluating Transportation Impacts in CEQA, at 10 (Dec. 2018).

OPR also advises that CEQA Guidelines Section 15064.7(c) allows agencies to consider the thresholds recommended by other public agencies. Accordingly, many agencies are working with regional transportation agencies to establish regionwide thresholds for different types of land uses. As of the date of this article, however, this effort is lagging in most regions.

For examples of how some agencies have implemented VMT processes and thresholds, look to the City of San Jose, the City and County of San Francisco, and the City of Los Angeles.

When Can LOS Still Be Used?

As noted above, LOS may still be used to measure CEQA transportation impacts for roadway capacity projects.

In addition, General Plans often define acceptable LOS for different types of roadways in the community. Therefore, LOS also may continue to be used as part of land use review processes, outside of CEQA, in order to determine whether a project is consistent with local land use policies.

For more information, contact SMW attorney Ellen Garber.