Assessment and mitigation of transportation impacts based on travel demand is required by state, federal, and local laws in California.
Determining trip generation is typically the first step in preparing these transportation impact analyses, and current industry standard practice
relies on trip rates published by the Institute of Transportation Engineers (ITE). However, ITE protocols emphasize vehicle trip rates without
sensitivity to urban context or socioeconomic characteristics, which can exaggerate the impact of certain land uses like affordable housing
developments, ultimately increasing mitigation fees. Updating trip generation methodologies is critical given the increasing demand for
affordable housing, especially in urban contexts.
This study builds on previous trip generation research in California and elsewhere, and examines trip generation rates for affordable housing
locations in Los Angeles and San Francisco Bay Area regions using a multi-method research design. Data were collected, assembled, and
analyzed to provide a robust picture of trip making, vehicle ownership, and mode use as a function of development characteristics, household
demographics, and urban setting. Results show a strong association between these factors and trip generation, and reiterate the need to revise
current industry standard practices. A discussion of policy implications, as well as suggested next steps in research and development, are
provided with this in mind.