Background
In 2013, Governor Brown signed Senate Bill (“SB”) 743 (Steinberg), which creates a process to change the way that transportation impacts are analyzed under California Environmental Quality Act (“CEQA”). Specifically, SB 743 changed the way that transportation impacts are analyzed under CEQA. Automobile delay metrics (i.e., level of service or “LOS”) will no longer be considered a significant impact under CEQA and the Governor’s Office of Planning and Research (“OPR”) recommends that jurisdictions instead use the Vehicle Miles Traveled (“VMT”) metric. OPR released a “Technical Advisory” (2018) containing methodologies and thresholds for VMT, but the Technical Advisory is not regulatory, only advisory.
OPR allows jurisdictions to retain their congestion-based standards (i.e., LOS) in general plans and for project planning purposes, but these standards will not be CEQA considerations. Developers in some cases are required to perform two different traffic analyses. Staff will update General Plan policies to accommodate congestion-based standards.
What is VMT?
VMT is a measure of the total amount of (miles) vehicular travel. For example, one vehicle traveling ten miles would equal 10 VMT. Four vehicles traveling ten miles would equal 40 VMT. Typically, development located at greater distance from other land uses or in areas with few transportation options generates more vehicle trips and trips of greater length (and therefore more VMT) than development located in close proximity to other uses or in areas with many transportation choices.
California Office of Planning and Research (“OPR”)
December 2018, OPR adopted the Technical Advisory on Evaluating Transportation Impacts in CEQA. OPR’s Technical Advisory contains recommendations regarding assessment of VMT, thresholds of significance, and mitigation measures as a resource for the public to use at their discretion. OPR indicates their guidance is only advisory, not mandatory. County staff has relied on this guidance, as well as information from various other sources (e.g., Fehr &
Peers (transportation planning and engineering firm), Contra Costa Transportation Authority, other local agencies, articles, and published research, etc.) to develop recommendations for VMT assessment, thresholds of significance, and mitigation measures for the unincorporated County.
Contra Costa County Transportation Analysis Guidelines (June 2020)
June 2020, the Board of Supervisors adopted new Transportation Analysis Guidelines (“Guidelines”) for implementing SB 743, including Vehicle Miles Traveled (“VMT”) as the metric for evaluating transportation impacts of proposed projects under CEQA.
Department of Conservation and Development (“DCD”) and Public Works Department (“PWD”) staff along with County Counsel and Fehr & Peers formed an interdepartmental working group (“working group”) for SB 743 implementation. The working group met biweekly to discuss development of policies, methodology, procedures, and implementation of VMT. The working group was also tasked with determining how the County will continue to use LOS as an evaluation tool for certain transportation facility operations.
Estimating VMT
The Guidelines provide screening criteria for projects that should be expected to cause a less-than-significant impact under CEQA and would not require further VMT analysis, absent substantial evidence indicating that a project would generate a potentially significant level of VMT. These types of “screenable” projects generally include:
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Projects generating fewer than 110 dial vehicle trips, or projects of 10,000 square feet or less of non-residential space, or 20 residential units or less.
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Residential, retail, office projects, or mixed-use projects proposed within ½ mile of an existing major transit stop or an existing stop along a high-quality transit corridor.
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Residential projects at 15% or below the baseline Countywide average VMT per capita, or employment projects at 15% or below the baseline Bay Area VMT per capita.
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Public facilities and government buildings.
The Guidelines recommend two methods for calculating VMT:
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Inserting the proposed project into the CCTA Countywide Model. Using the CCTA model to determine both trip generation and trip lengths allows consistent analysis methodology; or,
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Utilizing existing average trip length data of similar Traffic Analysis Zones (“TAZ”) that contain similar mixes of land uses.
A traffic analysis zone (“TAZ”) is a special area delineated by state and/or local transportation officials for tabulating traffic-related data, especially commute data. A TAZ usually consists of one or more census blocks, block groups, or census tracts. The CCTA model uses TAZs to better understand trip behavior and estimate trip length using socio-economic data (e.g., number of automobiles per household, household income, and employment within these zones).
Contra Costa Transportation Authority (“CCTA”)
February 2021, CCTA updated the Growth Management Program (“GMP”) Implementation Guide to include recommended methodology for compliance with the requirements of SB 743 and analysis of VMT for land use projects subject to CEQA. This guidance is intended to assist lead agencies in their CEQA VMT analysis consistent with new requirements of the CCTA GMP. The County’s Guidelines, which were adopted prior to CCTA adopting their updated GMP Implementation Guide, are consistent with the GMP Implementation Guide’s recommendations. |