Operational Performance Comparison of Video Detection Systems

摘要

Video detection has become increasingly popular for presence detection atrnsignalized intersections because of its versatility and ease of installation. However,rnseveral reports have documented performance problems in specific systems. Thisrnpaper quantifies the performance of three different commercially available videorndetection systems. The systems were tested in May and September 2005 for presencerndetection accuracy.rnPrior to the May 2005 test, a representative from each vendor configured thernvideo detection zones to match the loop detection zones as closely as possible. Thernoutputs from the loop detection for the through-right and left-turn lane groups wererncompared with the corresponding output from each of the video detection systems.rnWhenever there was a discrepancy between the loop and video, a digital video wasrnobserved to determine the cause of the discrepancy.rnMissed calls and false calls were categorized for each system. The errors werernalso categorized according to the impact that they would have on signal operations.rnDuring a 24hr test on two separate days, the number of missed detections longer than 5rnseconds ranged from 9 to 147, and the number of false calls longer than 5 secondsrnranged from 14 to 159. The loop detectors had one false call longer than 5 seconds andrnone missed call longer than five seconds during both tests.rnAlthough technology has advanced in the two years since this test wasrncompleted, the results documented in this paper apply to a large number of installationsrnthat have not been upgraded since the Fall of 2005. Furthermore, this paper highlightsrnthe importance of developing rigorous detection performance specifications so agenciesrncan make informed decision about the relative advantages and disadvantages ofrnalternative detection technology.