Pedestrian Injury Model
The Vehicle-Pedestrian Injury Collision Model predicts change in the number of collisions resulting in pedestrian injury or death associated with area-level changes in street, land use and population characteristics due to new development or transportation system changes. SFDPH uses this model to inform the need for pedestrian safety mitigations and improvements in the course of land use and transportation planning, to prevent people from being injured or killed by motor vehicles while walking on San Francisco streets. Significant predictors (census-tract level variables) in the current model are:
- Traffic volume
- Arterial streets (%, without MUNI Transit)
- Neighborhood commercial areas (%, land area)
- Land area (square miles)
- Employee population
- Resident population
- Below poverty level (%, population)
- Age 65 and older (%, population)
Background and Development
Primary preventable predictors of vehicle-pedestrian injury collisions are environmental, including: traffic volume, higher vehicle speeds, pedestrian volume, and intersection and street design factors. To achieve safe, walkable communities, planning professionals need practical tools to assess and mitigate the impact of land use and development plans and projects on pedestrian safety, including vehicle-pedestrian collisions. Currently, the tools available to evaluate the impacts of land use planning on pedestrian safety conditions are limited to existing conditions assessments of collisions or qualitative analyses of the pedestrian environment.
SFDPH began developing this multivariate model to understand how changes in traffic and other environmental factors impacted by development decisions in SF predict vehicle-pedestrian injury collisions. The model was developed in collaboration with the UC Berkeley School of Public Health and sought input from health, planning, and transportation professionals, and community advocates for pedestrian safety – both individually and through presentations at City staff and task force meetings, professional conferences, and academic settings – throughout the process. SFDPH published the pedestrian injury model findings in January 2009 in the professional scientific journal Accident Analysis and Prevention and is now writing a second manuscript detailing the practical application of the model to the Eastern Neighborhoods Area Plans in San Francisco. See the Peer Review Publications page on this site for more information on the published article.
SFDPH researchers developed the Vehicle-Pedestrian Injury Collision Model in collaboration with Edmund Seto, a UC Berkeley School of Public Health researcher and lecturer – drawing on traffic data generated from an on-going collaboration regarding the health impacts of traffic and transportation planning decisions.
Walking and public transit, as opposed to driving, are sustainable travel modes – and can be supported by safe environments that promote those behaviors. Land use and transportation planning processes provide an opportunity to assess pedestrian safety conditions for current and future San Francisco residents and workers, and to intervene to improve the pedestrian environment and support safe, sustainable transportation modes – provided there are tools to conduct these assessments.
Applications and Policy Targets
The main aim of the application of the San Francisco Vehicle-Pedestrian Injury Collision Model is to inform the need for pedestrian safety mitigations and improvements in the course of land use and transportation planning. Potential area-level interventions that improve pedestrian safety include planning and design decisions that reduce traffic volumes, speeds, and the need to drive, while promoting more walkable, safe environments including: transportation-land use planning coordination, transportation demand management measures, traffic calming, and street and intersection engineering countermeasures and amenities. The Victoria Transport Policy Institute’s online Transportation Demand Management Encyclopedia provides detailed information regarding these strategies.
SFDPH most recently used this model to assess potential impacts of Congestion Pricing policy being studied by the SF County Transportation Authority. SFDPH also used the model to analyze the impact of the Eastern Neighborhoods plans using estimated changes in resident population and traffic volume from the SF Planning Department in a technical review draft Impacts of Urban Land Use Development on Pedestrian-Motor Vehicle Collisions: An Application of the San Francisco Pedestrian Injury Model to Five Neighborhood Plans. The plans are expected to produce both a modest increase in local area traffic volume and a more substantial increase in the resident population. The model predicted that the plans’ implementation will result in increases in five-year pedestrian injury collision totals - by approximately 17% overall, or over 30 additional pedestrian injury collisions on those streets each year. SFDPH’s analyses were included in the Pedestrian Safety Assessment of the Eastern Neighborhoods Environmental Impact Assessment.