Development and Application of Portland Traffic System Performance Evaluation System

The city of Portland’s Traffic System Performance Evaluation (TSPE) system is an innovative, practical, and cost-effective tool for monitoring traffic system performance in response to federal, state, and local legislation. It has been designed, implemented, and applied using readily available traffic data. The TSPE goes beyond traditional level-of-service analysis and gives the city a means to identify operational deficiencies and provide a baseline for future performance monitoring. The TSPE includes five performance indicators that were crafted in response to questions about traffic performance and in recognition of the costs and availability of data to support performance evaluation. Each of the five indicators addresses a specific element of traffic performance. District accessibility measures the ease of access to and egress from major activity centers by examining the delay at gateway intersections. The street origin-destination characteristics indicator assesses the percentage of nonlocal trips on streets with different functional classifications. Travel time is measured on a set of specific routes between activity centers. The traffic flow indicator assesses the variation in speeds on major roadways. The multimodal service levels indicator assesses multimodal operational performance based on service levels for four different transportation modes (vehicular, transit, bicycle, and pedestrian) along a corridor. The system has proved to be relatively easy and inexpensive to apply. Other jurisdictions developing performance evaluation systems should consider integrating some components of the TSPE system.