Date of Award


Degree Name

Master of City and Regional Planning/MS in Engineering (Transportation Planning Specialization)


Civil and Environmental Engineering


Robert L. Bertini


This study investigates the effect of rainfall on transit performance measures at the route level in the Puget Sound region of Washington State. Transit agencies are required to report certain performance metrics to the Federal Transit Administration (FTA), but performance measures can also be used to evaluate service and provide customers with information regarding the transit system. Using a three-year sample of archived automatic vehicle location (AVL) and hydrologic data the relationships between ridership, travel time, delay, and rainfall were investigated. The analysis of daily ridership and rainfall resulted in no statistically significant results, however, the results are supported by the existing research in this field. There was a generally negative trend in ridership with respect to rainfall. The analysis of travel time and rainfall did not result in the expected outcome. It was hypothesized that travel time would vary with rainfall, but that was not always the case. During many rainfall events the travel time remained average. The analysis of delay and rainfall shows that the impact of rainfall on delay is more complex than assumed. The delay during dry trips was different than the delay during light and moderate rain, but during heavy rain the statistical different disappeared. These results, implications for transit operators, and future research opportunities are discussed.