The proposed study seeks to quantify the relationship between bus transit crashes and crash determinants at TriMet at the system level using a spatially disaggregate, risk-based approach. Increases in traffic volumes and land use intensification policies have made the operating environment for bus transit more difficult in recent years leading to increased safety concerns and heightened levels of risk. Examples of the types of transportation and land use factors influencing transit safety include higher levels of pedestrian and bicycle traffic, increases in population and employment density, and various “smart growth” design elements (i.e., narrow streets, on-street parking, retrofitting streets with pedestrian and bike facilities). The proposed research is made possible by the emergence of data from Intelligent Transportation Systems (ITS), data warehousing, and geographic information systems (GIS), which has created an opportunity to explore a dimension of safety that has... View Full Summary

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The proposed study seeks to quantify the relationship between bus transit crashes and crash determinants at TriMet at the system level using a spatially disaggregate, risk-based approach. Increases in traffic volumes and land use intensification policies have made the operating environment for bus transit more difficult in recent years leading to increased safety concerns and heightened levels of risk. Examples of the types of transportation and land use factors influencing transit safety include higher levels of pedestrian and bicycle traffic, increases in population and employment density, and various “smart growth” design elements (i.e., narrow streets, on-street parking, retrofitting streets with pedestrian and bike facilities). The proposed research is made possible by the emergence of data from Intelligent Transportation Systems (ITS), data warehousing, and geographic information systems (GIS), which has created an opportunity to explore a dimension of safety that has not been systematically analyzed — the transit operating environment. The study will empirically analyze accident frequency and severity using data extracted from multiple TriMet databases including the Accident/Incident Tracking System (ACID), the Bus Dispatch System (BDS), and Trans HR. These databases will provide information on vehicle characteristics, operating conditions, the nature of collisions and injuries sustained, and operator characteristics. Information on socio-demographics, land use, and transportation facilities will be drawn from geographic databases maintained by Metro and the City of Portland. The units of analysis will consist of approximately 7,000 route segments centered by bus stops. Land use and socio-demographic variables will be developed for a buffer around the roadway segment, using GIS tools. Spatially-referenced data commonly used for transit planning and traffic operations will provide the needed characteristics of the operating environment. A GIS will be used to identify bus accident locations over a multiyear period and to assign land use variables to each of the analysis segments.

TriMet, PSU Toulan School of Urban Studies and Planning

Project Type: Research
Start Date: October 1, 2007
End Date: January 31, 2010
Related Projects: None
Research Area: Healthy Communities