Effects of Average Speed Enforcement on Operating Speeds of Intercity Highways

Abstract

Average speed enforcement (ASE) system is an intelligent law enforcement means to prevent road users from speeding behaviors and to make better compliance with the speed limit(s) It is viewed as a powerful way for speed management Unlike traditional speed cameras which recognize the speeding events by recording spot speeds of each vehicle ASE cameras record the mean speeds of vehicles within the enforced section which effectively prevents drivers from the kangaroo driving behaviors In Taiwan the first ASE system was installed in Wan-li tunnel in 2018 to prevent speeding behaviors occurring inside the tunnel The results showed significant effects on reducing mean speeds and speed variations leading to a large number of applications for ASE systems proposed by local governments Therefore it is crucial to investigate the effectiveness of ASE systems installed and implemented in Taiwan In this research there are three study sites namely Wan-li tunnel Beiyi Highway 19 K to 23 1 K and Provincial Highway No 61 from 122 3 K to 130 2 K for the southbound The effects of ASE on average speeds the 85th percentile speeds and speed variations for the enforced sections are investigated by a before–and–after study Moreover the logistic regression method is applied to evaluate the effect of ASE enforcement on speeding behaviors more than 20 km/h over the speed limit via odds ratio comparisons As the results show the ASE system brings remarkable effects for decreasing the operating speeds and speed variations The odds of speeding events decrease by over 90% regardless of different types of vehicles different periods of the day or different highway geometric designs Finally this study also analyzes the spatiotemporal effect of ASE systems by the speed data collected by vehicle detectors (VDs) which provides significant speed reduction results

Date of Award	2020
Original language	English
Supervisor	Wei-Hsun Lee (Supervisor)