Citation

Bullock D, Sturdevant J, Day C. ITE J. 2008; 78(8): 20-23.

Copyright

(Copyright © 2008, Institute of Transportation Engineers)

DOI

unavailable

PMID

unavailable

Abstract

Although detection and control technology have evolved significantly over the past 30 years, the technology for continually assessing signal systems performance was developed in the 1970s. A critical reassessment is needed on how to define good practices for evaluating signal system performance using the present signal system infrastructure and accepted traffic engineering models. This paper describes procedures that illustrate how Highway Capacity Manual (HCM) concepts can be integrated with traffic signal system detection and controller status information to provide real-time performance measures characterizing the operation of a coordinated traffic signal system. Case studies are presented to illustrate these procedures. The three main parameters of the HCM delay equation that can be measured in real-time can be identified and used as performance measures for operational decisions on when traffic signal performance warrants adjusting parameters, conducting before/after assessments of signal timing adjustments to confirm that changes produce a measurable impact, and to document the status of an entire signal system with easily understood metrics. These performance measures can be extended to include other modes that interact with traffic signals.