CEQA Transportation Assessment – VMT Analysis
The California Environmental Quality Act (CEQA) requires that project-level transportation impacts are analyzed and mitigated effectively. With the enactment of Senate Bill 743 (SB 743), the traditional "Level of Service" (LOS) metric was shifted towards a more sustainable approach to transportation impact analysis. Vehicle Miles Traveled (VMT) is now used to assess transportation impacts under CEQA, emphasizing reductions in greenhouse gas emissions, encouraging infill development, and promoting more efficient land use patterns. This guidance provides an in-depth framework for conducting VMT assessments as part of the CEQA process, with specific focus on the methodologies, criteria, and screening mechanisms for evaluating land use projects in the City of Montebello.
VMT Analysis Methodology
Under SB 743, the City of Montebello uses a VMT analysis framework to assess transportation impacts for various land use projects. The intent is to evaluate whether a proposed project would increase the baseline VMT per capita for residential developments, VMT per employee for office developments, or total VMT for retail developments. The baseline data and assumptions utilized in the analysis should align with the existing conditions at the time the project’s Notice of Preparation (NOP) is issued, while the cumulative scenario should be based on the Southern California Association of Governments (SCAG) Regional Transportation Plan/Sustainable Communities Strategy (RTP/SCS) horizon year. All assumptions and methodologies are subject to review and approval by the City Traffic Engineer to ensure consistent, accurate analysis.
The VMT analysis methodology includes the following tools and resources:
- A flowchart that outlines the VMT analysis process, provided as Attachment A, "VMT Analysis Flowchart," helps streamline the analysis by clarifying each procedural step.
- A web-based assessment tool developed by SGVCOG (San Gabriel Valley Council of Governments) supports the screening and mitigation phases of VMT assessment. Detailed user guidance for this tool is available in Attachment B, "SGVCOG VMT Assessment Tool Users Guide."
Baseline and Cumulative Scenarios
The baseline scenario reflects the current transportation conditions at the project’s NOP issuance, capturing existing traffic patterns and VMT data. The cumulative scenario, aligned with SCAG’s RTP/SCS horizon year, projects future conditions with an emphasis on regional transportation and land use planning. By comparing the project’s anticipated VMT impact under these scenarios, the analysis provides a clear picture of both immediate and long-term impacts on transportation.
Project Screening
To streamline the VMT analysis process, three primary screening steps are used to identify projects that can potentially bypass a detailed, project-level VMT assessment. These screening steps focus on Transit Priority Areas (TPA), Low VMT Areas, and specific Project Types, which are discussed in further detail below.
Step 1: Transit Priority Area (TPA) Screening
Projects located within TPAs are generally presumed to have a less than significant VMT impact, provided certain criteria are met. TPAs are defined as areas within a half-mile radius of major transit stops or high-quality transit corridors. By promoting higher-density, transit-oriented development, TPAs align with the state’s goals of reducing greenhouse gas emissions and lowering reliance on single-occupant vehicles.
However, the presumption of low VMT impact does not apply if:
- The project has a Floor Area Ratio (FAR) below 0.75, indicating low-density development.
- The project proposes more parking than the city requires, potentially encouraging car use.
- The project is inconsistent with the SCAG Sustainable Communities Strategy, as determined by the City or lead agency.
- The project replaces affordable housing with moderate- or high-income housing, which could lead to increased VMT due to changes in household income levels and associated travel patterns.
To qualify for TPA screening, projects must ensure that all parcels are within the half-mile radius and meet other criteria, such as not exceeding a 10% threshold for residential units located outside the TPA. The SGVCOG VMT tool can assist in determining TPA eligibility, although the analyst should also confirm that transit service levels have remained consistent in the project area.
Step 2: Low VMT Area Screening
Residential and office projects located within identified low VMT-generating areas may be presumed to have a less than significant impact on VMT, provided they meet specified criteria. Low VMT areas are identified through SCAG’s travel forecasting model, which measures VMT generation within traffic analysis zones (TAZs). Projects in TAZs where VMT per capita or per employee falls below 85% of the regional average can qualify for screening.
The use of the SGVCOG VMT assessment tool can help determine if a project falls within a low VMT-generating TAZ. However, analysts should carefully evaluate the project’s land use type to ensure compatibility with surrounding areas. For instance, a residential project in a TAZ characterized by similar densities and housing types is more likely to maintain consistent VMT patterns. Conversely, if a project proposes a significantly different land use, it may alter travel patterns and invalidate low VMT assumptions.
Step 3: Project Type Screening
Certain project types are considered local-serving and are therefore assumed to have a minimal impact on VMT. These uses generally include essential services that serve the immediate community, thereby reducing the need for longer trips. The following project types can generally bypass a detailed VMT analysis:
- Local-serving schools, parks, and daycare centers.
- Local retail developments under 50,000 square feet, including gas stations, banks, and small restaurants.
- Affordable, supportive, and transitional housing within a half-mile of transit.
- Senior housing, assisted living facilities, and similar uses that tend to generate fewer trips.
Local-serving retail below 50,000 square feet typically improves convenience for local residents, potentially reducing trip distances by providing nearby amenities. Retail projects above this threshold may require a market study to determine whether they primarily serve local demand. Based on this assessment, the City Traffic Engineer may adjust the square footage threshold if the project’s impact on VMT is deemed minimal.
Projects Generating Fewer than 140 Daily Vehicle Trips
Projects that generate fewer than 140 daily trips, such as small housing or office developments, can also be presumed to have a less than significant VMT impact. This threshold aligns with typical trip generation rates, as outlined in ITE’s Trip Generation Manual, and accounts for the minimal impact of small-scale projects on overall VMT.
VMT Assessment for Non-Screened Development
Projects not qualifying for screening are required to complete a full VMT analysis, employing SCAG’s travel demand model or another approved sub-area model. The VMT analysis should include assessments for both baseline and cumulative scenarios, with adjustments to account for the project’s location, density, and other attributes.
Baseline and Project-Specific Scenarios
The analysis begins with establishing baseline conditions based on SCAG data, interpolated to the project’s NOP year. The “Baseline plus Project” scenario evaluates the VMT impact with the project’s proposed land uses added to the TAZ, comparing outcomes to established thresholds. For cumulative scenarios, the analysis should factor in future growth assumptions from SCAG’s RTP/SCS, adjusting for any substantial land use changes.
Analysis and Metrics
For office and residential projects, VMT per capita or VMT per employee metrics are typically used to assess impact significance. For retail projects, a total VMT metric is more appropriate, reflecting the retail sector’s broader effect on regional travel patterns.
Our Services are available throughout City of Montebello of LA County with Zipcode 90640