CEQA Assessment - VMT Analysis for City of Moreno Valley Traffic Impact Preparation Guide

CEQA Assessment - VMT Analysis

Introduction to VMT Analysis Under CEQA

A key element of Senate Bill (SB) 743, signed into law in 2013, is the shift away from using automobile delay and Level of Service (LOS) as the primary metric for determining transportation impacts under the California Environmental Quality Act (CEQA). Instead, Vehicle Miles Traveled (VMT) has been identified as the preferred measure for assessing transportation-related environmental impacts. The latest CEQA guidelines, issued in December 2018, establish VMT as the most appropriate metric for evaluating transportation efficiency and project impacts. However, SB 743 does not prevent cities and counties from continuing to analyze LOS for local planning efforts, such as the General Plan, traffic studies, and ongoing network monitoring.

The following guidelines assist in determining VMT impact thresholds and necessary mitigation measures for various land use projects.

Analysis Methodology

To comply with SB 743, a VMT analysis must be conducted for land use projects that have the potential to increase the average VMT per capita or employee beyond the City’s established threshold. The City’s transportation efficiency standards are based on comparing the proposed project’s VMT generation to the baseline average across the incorporated area.

These guidelines are informed by the Western Riverside Council of Governments (WRCOG) Implementation Pathway Study, which provides methodologies for screening and analyzing VMT impacts. The study outlines the methodologies and significance thresholds necessary to evaluate transportation impacts comprehensively.

Baseline VMT Methodology and Data

WRCOG established baseline VMT calculations using data from multiple sources, including:

• The Southern California Association of Governments’ (SCAG) Regional Transportation Plan travel forecasting model.

• The Riverside County Transportation Analysis Model (RIVTAM) and the Riverside County Model (RIVCOM).

• The California Household Travel Survey, which was used to validate model-derived estimates of home-based VMT.

WRCOG has also developed a screening tool based on the RIVTAM/RIVCOM model inputs and outputs. This tool allows for an initial assessment of potential VMT impacts and provides supporting evidence for determining whether a project’s impact is considered significant.

Project Screening Criteria

Projects can be screened from further VMT analysis if they meet specific criteria. Three types of screening methods can be applied to determine whether a project requires a detailed VMT assessment:

Step 1: Transit Priority Area (TPA) Screening

Projects located within a TPA may be presumed to have a less-than-significant impact unless substantial evidence suggests otherwise. A TPA is defined as an area within a half-mile radius of an existing major transit stop or along a high-quality transit corridor. A project may not qualify for TPA screening if it:

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

• Provides more parking than required by the local jurisdiction.

• Is inconsistent with the Sustainable Communities Strategy (as determined by the lead agency and the Metropolitan Planning Organization).

• Replaces affordable residential units with fewer moderate- or high-income residential units.

Step 2: Low VMT Area Screening

Projects in areas with existing low VMT per capita or employee may also be presumed to have a less-than-significant impact. WRCOG utilized the RIVTAM model to identify these low VMT areas, which are measured using Traffic Analysis Zones (TAZs). To qualify for low VMT area screening, a project must be consistent with existing land use patterns in that TAZ. The WRCOG screening tool can be used to verify eligibility for this presumption.

Step 3: Project Type Screening

Certain local-serving land uses can be presumed to generate minimal VMT and, therefore, have a less-than-significant impact. These include:

• Local-serving retail projects under 50,000 square feet.

• Local-serving K-12 schools.

• Local parks and recreation centers.

• Daycare centers.

• Local-serving gas stations, banks, and hotels.

• Student housing projects.

• Local-serving community colleges aligned with regional planning assumptions.

• Projects generating fewer than 400 daily vehicle trips.

VMT Assessment for Non-Screened Projects

If a project does not qualify for screening, a full VMT analysis must be conducted using the RIVTAM/RIVCOM model. This analysis requires assessing VMT under the following conditions:

Existing Conditions

This scenario evaluates the baseline VMT for the project’s TAZ using the latest available data. This provides a reference point for determining the project’s impact.

Existing Plus Project Scenario

This scenario incorporates the proposed project into the TAZ model and evaluates how it affects VMT across the roadway network. The model output must be reviewed for accuracy, ensuring that production and attraction balancing is correctly accounted for. If this scenario results in a less-than-significant impact, no further cumulative analysis may be required.

Cumulative No Project Scenario

This scenario projects VMT levels for the planning horizon year without the proposed project, providing a future baseline.

Cumulative Plus Project Scenario

This scenario models the project’s long-term impact by adding it to the cumulative no-project forecast. Land use adjustments may be necessary to account for the redistribution of population and employment growth. The results must be interpreted carefully to avoid overestimating the project’s effect on VMT.

Types of VMT Analysis

Each “plus project” scenario must include two key types of VMT analysis:

1. Project-Generated VMT: This measures the VMT produced per capita or employee and compares it to the established threshold.

2. Project Effect on VMT: This evaluates the change in citywide or regional VMT resulting from the project’s addition to the network.

VMT data is extracted from the travel demand model using origin-destination trip matrices, which are then multiplied by final assignment skims. Additionally, total VMT by speed bin should be included in air quality, greenhouse gas (GHG), and energy impact analyses.

Thresholds of Significance

The project-generated VMT is compared against the City’s VMT threshold to determine if mitigation is required. If a project is expected to generate excessive VMT, mitigation strategies should be implemented to reduce its impact.

Mitigation Strategies for High-VMT Projects

If a project is found to have a significant impact on VMT, mitigation measures must be considered. Potential mitigation strategies include:

• Enhancing access to public transit.

• Implementing Transportation Demand Management (TDM) strategies such as ridesharing programs, telecommuting incentives, and improved bicycle/pedestrian infrastructure.

• Increasing land use density or mixed-use development to reduce travel distances.

• Reducing parking supply to discourage excessive vehicle use.

• Encouraging alternative transportation modes through improved infrastructure and amenities.

As SB 743 shifts CEQA transportation impact analysis from LOS to VMT, projects must be evaluated based on their potential to increase travel distances and vehicle dependency. The WRCOG screening tool and modeling methodologies provide a structured approach to assessing VMT impacts and identifying appropriate mitigation measures. By aligning projects with regional and local transportation goals, cities can promote sustainable land use and mobility while minimizing environmental impacts.

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