Outcome-Oriented Performance Measures for Management of Signalized Arterial Capacity

The design of traffic signal timing plans is typically based on a single day of manual turning movement counts. Once systems are constructed and settings are implemented, they receive maintenance on fixed schedules of a number of years. Public feedback (e.g., phone calls) is in many cases the primary channel by which an agency obtains feedback about the system. System assessment is often conducted by collecting a new small data sample and repeating the design process. One common and frustrating result is that the same settings are frequently recommended by the design software even when problems are known to exist. This paper illustrates how fundamental traffic engineering concepts can be integrated with traffic signal system detection and controller status information to provide outcome-based measures of arterial-system performance. These outcome-based measures of performance characterize the operation of a signal system and provide a data set that can be used to identify and prioritize opportunities for operational improvements in the system. A consistent set of performance measures used across a signal network would affect traffic signal operations at two distinct levels. At the regional or district level, it would provide a continuously updated list of problem areas with greater accuracy than telephone reports. At the agency jurisdiction level, it would provide quantitative data for prioritizing resources across multiple districts and by time of day.