Shifting from LOS to VMT would save time, money, and better support local goals

By Beth Osborne

Two recent studies suggest that California’s change in assessing the impact of development—from level of service (LOS) to vehicle miles traveled (VMT)—can reduce costs for developers and streamline the review of projects. Under the new guidelines, both studies to determine transportation impacts and any mitigation measures after review are less costly than the previous requirements. This has been confirmed not just by academic studies, but also by the City of Pasadena in a paper by recently-retired Director of Transportation, Fred Dock.

Many cities still use level of service—a measure of how close to free-flow traffic is moving—to determine whether new trips from a proposed development will affect adjacent roads. Because traffic flow is the primary objective, developers are often required to pay for expansions to the roadway system or to lower the density of their proposed development to lessen the traffic impact. They must also pay for expensive traffic studies to determine if LOS will be affected.

This approach raises the overall cost of development, especially in denser urban environments, and pushes development to the edges of town, which increases overall VMT and associated pollution and hampers active transportation. Because the result is undermining the environmental, budgetary, and livability goals of many areas, urban planners have begun to search for a different way to evaluate the impact of development on the transportation system.

In 2014, a new California law was passed that replaced LOS with VMT in traffic impact analysis for large land use projects, supporting the state’s goals to encourage infill development and mode shift, meet environmental goals, increase livability, increase housing supply, and bring down the cost of housing throughout the state.

Under the VMT approach, planning agencies screen a development project to determine whether it would cause significant VMT impact. Only if the project could not be screened would the agency require a more detailed analysis to determine whether the impacts would require specific mitigation. Infill development is less likely to cause significant VMT impacts than significant LOS impacts. And this screening is also less time-consuming and expensive than the comparative LOS analysis. This is a benefit to both developers and local agencies.

Two recent studies found that a shift from LOS to VMT would save time and money in development projects.  In the Journal of the American Planning Association, Jamey M. B. Volker, Amy Lee, and Dillon Fitch of UC Davis Institute of Transportation Studies published “Streamlining the Development Approval Process in a Post–Level of Service Los Angeles.” In this study, they analyzed the VMT approach using 153 projects in the Los Angeles area, including residential, commercial, and mixed-use development projects. They found that nearly 65 percent of the projects could have been screened; that is, they would have been determined to have no significant VMT impact. Those lead agencies would therefore not have to prepare, nor would the developer have to pay for, further analysis, saving substantial time and funding.  Housing projects benefit the most, with 76 percent of residential-containing projects likely being streamlined, compared with about 39 percent of nonresidential projects.

In another article, “Leaving level-of-service behind: The implications of a shift to VMT impact metrics,” Amy Lee and Susan Handy studied the impact of a VMT metric on streamlining development projects. They also found that a VMT review would be less burdensome overall but particularly for projects that would reduce travel demand because of their location or design, while LOS metrics would lead to the building of expensive, capacity-increasing mitigation measures to ease vehicle delay. The LOS approach both undermines the climate and livability goals of many California communities while being ineffective at solving the congestion problem caused by misplaced land use development.

Besides the objective of prioritizing environmental goals and infill development over the free flow of motor vehicle traffic, the change from LOS to VMT as the basis for determining required mitigation also appears to be a cost saving measure for local agencies and developers.

Beth Osborne is Senior Policy Advisor for SSTI.