Transportation Demand Management
Case Study – San Francisco: Transportation Demand Management (TDM) Program
Use of Mandated Targets and Flexible Regulations to Manage Transportation Demand
Overview of Project
The San Francisco Transportation Demand Management (TDM) Program’s primary purpose is to reduce vehicle miles traveled (VMT) generated by new development projects in the City and County of San Francisco. The Program is designed in conjunction with developers and its main intent is to shift travel to and from new developments by providing a series of development-focused TDM measures. Examples of TDM measures include “unbundling” parking from lease costs, providing bicycle parking and amenities, subsidized transit passes, and carshare and vanpool programs.
The San Francisco Planning Code contains definitions for over 100 different land uses. To simplify the applicability of the TDM Program, the TDM Program Standards classify land use code definitions into four land use categories—retail, office, residential, and other. The TDM Program Standards rank the four land use categories from highest to lowest, according to the estimated number of motor vehicle trips per parking space provided for that primary user: visitors and customers, employees, or residents. The online TDM Tool shows the TDM Program elements. These include parking demand management, active transportation facilities and support (bicycling and walking), high occupancy vehicle use incentives (public transit, vanpools), car share, and other measures to reduce private motor vehicle trips.
San Francisco’s TDM Program is regulatory but flexible in nature. The City and County of San Francisco has mandated standards that eligible buildings must meet, but project sponsors or property owners may choose how they meet these requirements. The TDM Program applies to new residential developments with at least 10 dwelling units or bedrooms and new commercial developments that span 10,000 square feet or more.
Policies and Ordinances Contributing to Project Success
The TDM Program Standards are the culmination of years of work and research summarized in the TDM Technical Justification document. In 2014, San Francisco voters passed two funding measures to improve public transit and create safer streets in neighborhoods citywide. San Francisco voters have consistently reaffirmed the city’s transportation planning direction and supported environmentally-friendly transportation options.
Consistent with the City and County Interagency TDM Strategy, the TDM Plan’s effectiveness will be evaluated by tracking changes in solo driving, measured by single occupancy vehicle (SOV) trips. Other indicators of the strategy’s success will include changes in transportation behavior and transportation impacts indicated by other key metrics such as VMT and greenhouse gas emissions. The Resolution in Support of the Transportation Demand Management Resolution provides a clear policy rationale and guidance for implementation.
Challenges and Lessons Learned
In the strong economy of 2017 and 2018, developers have actively participated in the TDM Program since they have an economic incentive to gain timely approval for their projects. City staff report that developers value the flexibility provided in the TDM Program to meet mandated targets in the most feasible way given the specific circumstances of their projects.
As more and more projects come online, the City will gather data and analysis to identify what is most effective and why, determine measures that can be improved, and disseminate best practices. City staff note that direct measurements like the number of bicycle trips caused by specific building plans are often difficult to quantify. Monitoring will depend largely on intercept surveys, whereby researchers stop people as they are coming in and out of specific buildings. Other potential methods include special surveys and journals in which participants record their daily travel. Metrics that will be reported by these measures include reduced motor vehicle trips due to TDM measures, as well as the travel mode share (e.g. drive-alone, transit, bicycle, walking) of the project after full TDM program implementation.