An Alternative to Auto LOS for Transportation Impact Analysis

Automobile Level of Service (LOS) standards are the measure of the adequacy of roadways to serve vehicle demand. Increasingly, research is published on alternatives to conventional automobile LOS. Practicing transportation planners have also shown increasing interest in applying these alternative tools, particularly in urban locations encouraging multimodal transportation systems or infill development. Much of the research and activity on alternatives to auto LOS has focused on two approaches: (1) creating transportation performance measures to complement auto LOS, such as “user based” LOS measures for transit, bicycling, and walking; and (2) applying conventional auto LOS standards more flexibly. Neither approach is likely to effectively address the shortcomings of auto LOS as the measure of transportation impact in urban, multimodal contexts. The approaches are particularly unlikely to be effective where state law requires formal standards for transportation facilities and significant public and private sector resources have been dedicated to achieving auto LOS conformity. This paper presents an alternative to auto LOS for environmental impact analysis purposes under investigation by the San Francisco County Transportation Authority, developed to support the transportation system development objectives of an urban, multimodal context, and to respond specifically to the legal requirements and constraints of California’s environmental impact analysis requirements. Local jurisdictions with similar situations, such as urban areas with growth management, concurrency management, or public facilities requirements, may find these alternatives more effective than the user-based measures and flexible auto LOS applications most frequently discussed in the literature.