The City of San Marcos sought to develop transportation study guidelines to meet state requirements for vehicle miles traveled (VMT) reductions while also accommodating local traffic needs.


Kittelson prepared updated Transportation Impact Study (TIS) Guidelines, which provide methodologies and impact thresholds for the evaluation of VMT to replace previous automobile level of service (LOS) metrics, and City-specific significance thresholds, analysis methodologies, and processes/procedures for the evaluation of new development and transportation projects. To help mitigate projects’ VMT impacts, we also researched transportation demand management (TDM) strategies and updated an off-model regional VMT spreadsheet tool based on measures and factors more relevant to the local context. Finally, we conducted research into the potential establishment of a new impact fee to mitigate VMT-related impacts.

The Outcome

Adapting to a New Way of Measuring Transportation Impacts

The City’s updated guidelines document sets out how to analyze development projects using new VMT metrics to reduce citywide VMT and greenhouse gas emissions. The guidelines also include requirements for assessing effects on vehicles, bicyclists, pedestrians, and transit users to maintain local quality of life as new development projects are constructed.


San Diego


City of San Marcos


San Marcos, CA