VMT Analysis Methodology for Land Use Projects in City of Torrance

VMT Analysis Methodology for Land Use Projects in City of Torrance 

4.0 VMT Analysis Methodology

4.1 Overview

When a project does not qualify under any of the screening criteria outlined in Section 3.2, it is required to undergo a full Vehicle Miles Traveled (VMT) analysis. The purpose of this analysis is to estimate the VMT impact of the project and determine its consistency with the significance thresholds established in Section 5.0.

The process involves evaluating the project on two primary levels:

1. Project-Level VMT Impact Significance: This initial evaluation determines the direct VMT impact generated by the project.

2. Cumulative VMT Impact Significance: If required, this additional analysis examines the project’s impact in the context of broader regional or long-term transportation patterns, as detailed in Section 4.6.

For projects incorporating transportation demand management (TDM) strategies, the VMT analysis must include two scenarios: one that reflects the baseline conditions (“without TDM”) and another that accounts for the expected reductions in VMT due to the implemented strategies (“with TDM”). This ensures that the potential mitigation effects of TDM measures are transparently evaluated.

4.2 Estimating Tool

The analysis relies on the Southern California Association of Governments (SCAG) Regional Travel Demand Model (RTDM) from 2012. This model provides the data necessary to estimate VMT values and is integral to the evaluation process. The SCAG RTDM ensures consistency in VMT estimates across projects and enables comprehensive regional transportation planning.

4.3 VMT Metric

The appropriate VMT metric is essential for evaluating the transportation impact of a proposed project. This section outlines the metrics, typical land uses, and considerations for unique or mixed-use projects.

4.3.1 VMT Metrics

The SCAG RTDM reports the following VMT metrics, which vary based on the type of land use under consideration:

• Residential VMT per Capita: This metric calculates the total length of daily home-based trips produced within the analyzed area, divided by the population residing in that area.

• Employment VMT per Employee: This metric determines the total length of daily home-based work trips attracted to the analyzed area, divided by the number of employees working there.

• Total VMT per Service Population: This metric evaluates the total length of all daily trips to and from the analyzed area, divided by the service population, which includes both residents and employees.

• Total VMT: This metric assesses the total daily VMT for all Transportation Analysis Zones (TAZs) within the study area. It is commonly used for larger, regional-serving land uses.

4.3.2 Typical Land Uses

Different land uses require different VMT metrics for analysis. Table 1 identifies the VMT metrics applicable to various land use categories:

Before initiating the analysis, the appropriate land use and corresponding VMT metric must be confirmed with the City Traffic Engineer to ensure alignment with local and regional planning standards.

4.3.3 Unique Land Uses

For projects that do not fit into the standard categories listed in Section 4.3.2 (e.g., fulfillment centers, conference centers, sports venues), the VMT metric is determined on a case-by-case basis. The City Traffic Engineer must approve the selected metric, ensuring that it accurately reflects the project's impact on transportation patterns.

4.3.4 Mixed-Use Projects

Mixed-use projects require a more nuanced analysis. Each component of the project must be evaluated individually based on the metrics outlined in Section 4.3.2 or 4.3.3. This approach ensures that the diverse elements of a mixed-use project are appropriately accounted for in the overall VMT analysis.

4.4 Analysis Year

The timing of the analysis is critical for determining the relevance and accuracy of VMT estimates. Two distinct analysis years are considered:

4.4.1 Project-Level VMT Analysis Year

The project-level VMT analysis corresponds to the opening year of the project. This baseline assessment uses linear interpolation to estimate VMT values for the project’s opening year based on data from the 2012 SCAG RTDM, which includes a base year of 2012 and a forecast year of 2040. This method ensures that the analysis reflects the most current conditions likely to exist when the project becomes operational.

4.4.2 Cumulative Impact VMT Analysis Year

For cumulative impact evaluations, the analysis year is set to 2040, the forecast year for the SCAG RTDM. This long-term perspective is essential for understanding how the project interacts with regional transportation networks and land-use patterns over time. The 2040 analysis ensures alignment with the SCAG Regional Transportation Plan/Sustainable Communities Strategy (RTP/SCS).

4.5 Steps for Conducting VMT Analysis

To perform a comprehensive VMT analysis, the following steps are undertaken:

1. Identify Project Characteristics: Determine the project’s land use type, location, size, and operational details.

2. Define Study Area: Establish the geographic boundaries for the analysis, typically defined by TAZs.

3. Confirm VMT Metric: Based on the project’s characteristics, select the appropriate VMT metric with input from the City Traffic Engineer.

4. Estimate Baseline VMT: Use the SCAG RTDM to calculate the baseline VMT values for the analysis year.

5. Evaluate Significance: Compare the estimated VMT values against the thresholds established in Section 5.0 to determine the project’s transportation impact.

6. Incorporate TDM Strategies: If applicable, adjust the VMT estimates to reflect the implementation of TDM measures and reevaluate significance.

4.6 Cumulative VMT Impact Analysis

Cumulative impact analysis evaluates how the project contributes to regional transportation patterns and whether it aligns with long-term planning goals. This analysis considers:

• Regional Context: The project’s alignment with the SCAG RTP/SCS and other regional plans.

• Cumulative Growth: The interaction between the project and anticipated future developments.

• Mitigation Measures: The effectiveness of any proposed measures to offset cumulative impacts.

Projects demonstrating significant cumulative VMT impacts may need to propose additional mitigation measures or justify their alignment with broader regional goals.

4.7 Reporting and Documentation

The results of the VMT analysis must be documented in a clear and detailed report. Key components include:

• Executive Summary: A high-level overview of the findings.

• Methodology: A description of the tools, data, and assumptions used in the analysis.

• Results: The estimated VMT values and their comparison to significance thresholds.

• Mitigation Measures: Any proposed strategies to reduce VMT impacts.

• Appendices: Supporting data, including maps, tables, and technical documentation.

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