California Air Resources Board

SACRAMENTO - A new tool to help local governments and regional planners evaluate the impact of policy-relevant variables on vehicle miles traveled — taking into account the unique attributes of each community — is available online, the California Air Resources Board announced today.  This tool offers look-up tables that provide neighborhood-scale VMT elasticities and marginal effects associated with changes in land use and transportation variables for city, county and regional geographic areas.

This tool is not a scenario planning tool, but rather will help inform more targeted local policies to reduce car driving. Policy options include road pricing, incentivizing infill development, implementing mixed-use zoning, implementing complete streets and adding transit routes and increasing transit service frequency.

A training to educate cities, counties and metropolitan planning organizations on how to use the tool and interpret results is set for 1:30 to 3:30 p.m. on May 1 at Cal/EPA Headquarters, Klamath Training Room, 1001 I Street, Sacramento.

Training participants will learn about an ARB-funded research project to develop the tool, which was completed by the Institute for Transportation Studies at UC Davis. Researchers collected relevant local data, such as the percent of commuters using transit, and used multiple statistical methods to estimate changes in VMT based on changes in local land use and transportation variables. The tool allows users to select any city, county, or MPO in California and review the changes in VMT that are correlated with changes in variables, such as transit use, road density and job access. For example, modestly increasing commuter transit ridership in Los Angeles from 11.74 percent to 12.9 percent may lead to a reduction of LA’s VMT by as much as 1.4 percent.   

Tool users also can drill down to see what type of neighborhood — central city urban versus rural, for example — would see the biggest reductions in VMT when changes are made to policy-sensitive variables.

Until now, little information has been available to help quantify how changes in land use and transportation variables might lead to local changes in VMT. Local estimates are important because one strategy does not likely have the same impact across different types of neighborhoods. For example, increasing public transit in an urban area that already has a robust transit system may lead to a greater change in VMT than introducing public transit to a rural area with little ridership potential.

Strategies to reduce VMT in each jurisdiction should be tailored to each neighborhood type.  Higher gasoline prices, for instance, are clearly associated with lower VMT in the middle range of neighborhood types (urban/suburban), but are not associated with lower VMT in either “Central City” or “Rural” neighborhoods. The effect on VMT of improving job access likewise is highly variable across neighborhood types, with the largest absolute effect of local jobs seen in the “Rural” and “Suburb, Single Family Homes” neighborhood types, where current job access is somewhat limited.

The research also found that there are large VMT differences between people living in different neighborhood types in California. In fact, average household daily weekday VMT is—on average—three times larger in suburban, single-family home neighborhoods than in central city neighborhoods.

The tool can also help elected officials and professional planners in their efforts to evaluate policies to reduce VMT in order to comply with AB 32 and SB 375. Cars and trucks generate more than one-third of California’s greenhouse gas emissions annually. While much is being done to reduce vehicle-related emissions to meet the goals of AB 32, an overall reduction in VMT is also critical for the state to achieve its climate goals in 2020 and beyond. In addition, SB 375 requires each of California’s metropolitan planning organizations to create a Sustainable Community Strategy that identifies how the region will achieve greenhouse gas reduction targets through land use, housing and transportation planning.

To RSVP for the May 1 training or for more information contact Dana Papke Waters at (916) 324-9615 or dpapke@arb.ca.gov.

Click here to view the tool, final report, and summary for policy makers for the research project, “Quantifying the Effect of Local Government Actions on Vehicle Miles Traveled,” on ARB's website.