Transportation Impact Analysis (TIA) Guidelines
The TIA Guidelines document (last updated October 2014) presents VTA's guidelines for preparing Transportation Impact Analyses (TIAs).
Transportation Impact Analysis Guidelines are prepared to assess the transportation impacts of land development projects and to assist in identifying whether improvements are needed to the roadways, bike routes, sidewalks, and transit services affected by the project.
As the Congestion Management Agency (CMA) for Santa Clara County, VTA establishes the TIA Guidelines that local agencies use when analyzing the transportation impacts of land development projects on the transportation system. The Guidelines are also often used by local agencies as a reference for the Transportation Analysis in environmental documents.
October 2014 VTA Transportation Impact Analysis Guidelines
A new version of the VTA Guidelines was adopted by the VTA Board of Directors in October 2014, the culmination of a two-year update process with extensive stakeholder involvement. The new Guidelines include updated procedures for documenting auto trip reductions, analyzing non-auto modes, and evaluating mitigation measures and improvements to address project impacts and effects on the transportation system.
- VTA Transportation Impact Analysis Guidelines – October 2014 – Full Document
- VTA TIA Guidelines – October 2014 – Main Document only
- VTA TIA Guidelines – October 2014 – Appendices only
There are two TIA-related forms that are included in the TIA Guidelines document:
- TIA Notification Form - refer to Section 3.1 and Appendix B (Fillable PDF) (11-4-2014 version)
- Auto Trip Reduction Statement - refer to Section 8.2 and Appendix C (Fillable PDF) (11-4-2014 version)
For an accessible version of these documents or if your assistive technology requires a different format, please contact Robert Swierk, Senior Transportation Planner, at (408)321-5949 and we will try to accommodate you.
Vehicle Miles Traveled (VMT) Resources
Starting in July 2020, Lead Agencies under the California Environmental Quality Act (CEQA) are required to use Vehicle Miles Traveled (VMT) as the primary metric for CEQA transportation analysis of proposed land use projects. Beginning in September 2020, Caltrans began requiring the use of VMT in CEQA analysis of projects that increase roadway capacity on the State Highway System. These changes came about in response to California Senate Bill 743, enacted in 2013.
Vehicle Miles Traveled Analysis of Land Use Projects
VTA has provided several resources to assist cities and the County in conducting VMT analysis of land use projects, in its Congestion Management Agency (CMA) role.
These resources are meant to supplement, rather than replace, those provided by the California Natural Resources Agency and the Governor’s Office of Planning and Research. Each Lead Agency should consult with CEQA experts and legal counsel regarding their own CEQA practices, including the use of VMT in transportation analysis.
Base VMT Estimates from the VTA Model
In February 2020, VTA provided Base VMT estimates for a base year of 2015, prepared using the VTA travel demand model, to the 15 cities and the County of Santa Clara.
- VTA estimated that 2015 Residential VMT per Capita (Home-Based VMT for all trip purposes, divided by total population) across Santa Clara County is 13.33 VMT per person, per weekday.
- For non-residential land uses, VTA estimated that 2015 Employment VMT Per Job (Home-Based Work VMT, divided by total jobs) across Santa Clara County is 16.64 VMT per job, per weekday.
- VTA provided map files to the cities and County to allow them to produce “heat maps” of Residential and Employment VMT in their jurisdictions.
Santa Clara Countywide VMT Evaluation Tool for Land Use Projects
VTA has developed a countywide, web and Geographic Information Systems (GIS)-based tool, called the Santa Clara Countywide VMT Evaluation Tool that offers the following:
- Helps users conduct a baseline VMT screening evaluation for small- to medium-sized residential, office and industrial land use projects in Santa Clara County. The Tool is capable of evaluating these land uses individually, in combination with each other, and with or without local-serving retail.
- Screens land use projects to determine whether further VMT analysis is necessary, by identifying whether projects fall within a low-VMT area according to the applicable jurisdiction’s VMT threshold, and/or whether they fall within proximity to transit.
- Estimates the project-generated VMT associated with the project using VMT data from a travel demand model at the specific project location, and calculates project-generated VMT after reductions from certain VMT-reducing measures have been applied.
VTA launched the first version of the Countywide VMT Evaluation Tool in May 2020, and released Version 2 of the tool which includes updates based on user feedback in September 2021.
- Santa Clara Countywide VMT Evaluation Tool: https://vmttool.vta.org
- VMT Evaluation Tool Version 2 Quick Start Guide (September 2021)
- VMT Evaluation Tool Version 2 Frequently Asked Questions (December 2021)
Vehicle Miles Traveled Analysis of Transportation Projects
As noted above, beginning in September 2020, Caltrans began requiring the use of VMT in CEQA analysis of projects that increase roadway capacity on the State Highway System (SHS).
VTA sometimes serves as a CEQA Lead Agency on roadway projects on the SHS, such as for expansions of the Silicon Valley Express Lanes network. In other cases, VTA conducts planning, design and engineering on projects where Caltrans is the CEQA Lead Agency, such as interchange reconfiguration projects.
Caltrans has provided technical guidance to support analysis of transportation impacts of projects on the SHS through the use of VMT. VTA staff provided input during the development of this guidance.
Local VMT / Transportation Analysis Policies
The changes to the CEQA Guidelines enacted in response to Senate Bill 743 have led cities and counties across California to revisit how they conduct transportation analysis of proposed projects. Many cities have already adopted new policies establishing how they will conduct VMT analysis, what their thresholds will be for VMT impacts, and what screening criteria they will use to determine whether projects require VMT analysis.
As of Fall 2021, nine cities in Santa Clara County have taken a City Council action to adopt VMT thresholds and screening criteria for CEQA transportation analysis:
- Los Gatos
- Mountain View
- Palo Alto
- San Jose
- Santa Clara
Other cities and the County are currently using VMT in CEQA analysis on an ad hoc basis, as permitted by law and CEQA practice.
Traffic Level of Service (LOS) Analysis Guidelines
The LOS Analysis Guidelines document (last updated June 2003) presents analysis methodologies that must be used to evaluate LOS on CMP roadway facilities within Santa Clara County.
Local Model Consistency Guidelines
The Local Model Consistency Guidelines document (last updated May 2009) describes the process the local agencies should consider in order to develop models consistent with the VTA Countywide models, and the steps that will be required to certify model consistency.
Deficiency Plan Requirements
Deficiency plans, as it relates to traffic congestion management, are plans that identify offsetting measures to improve transportation conditions on the Congestion Management Program (CMP) facility in lieu of making physical traffic capacity improvements such as widening an intersection or roadway. The purpose of this document is to provide Member Agencies with specific details on deficiency plan preparations, content requirements, approval process, monitoring, and responsibilities.
The VTA Deficiency Plan Requirements (last updated September 2010) is an update to the existing “Requirements for Deficiency Plans” document adopted on November 18, 1992. The VTA Deficiency Plan Requirements document has been simplified and updated to focus on providing instructions on developing deficiency plans, to reflect current practices, policies, and procedures that were not yet established when the existing document was developed, and to be consistent with the recently updated VTA Transportation Impact Analysis (TIA) Guidelines.