Safety Evaluation Of Red Light Cameras

Author : Ramesh Otturu
Publisher :
ISBN 13 :
Total Pages : 154 pages
Book Rating : 4.:/5 (87 download)

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Download or read book Evaluation of the Effectiveness of Red Light Cameras to Improve Safety written by Ramesh Otturu and published by . This book was released on 2012 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt: The main objective of this thesis is to evaluate the effectiveness of red light cameras (RLCs) in improving safety at signalized intersections. Two scenarios were considered in order to evaluate the effectiveness of RLCs. Firstly, crashes before the installation of RLC were compared with crashes after the installation of RLC. Secondly, crashes after the installation of RLC were compared with crashes after the termination of RLC. Considering both the scenarios helps to determine whether the safety increased or decreased after the installation and after the termination of RLC. This study used red light running crashes and total crashes to evaluate the effectiveness of RLCs. Data for 36 intersections in the city of Charlotte, NC, where RLCs were installed in 1998 and terminated in 2005, were used for evaluation. The year 1997 was considered as before the installation period while 1999 to 2004 was considered as after the installation period. The year 2005 to 2010 was considered as after the termination period. Data for years 1998 and 2005 was not considered to minimize novelty effects. Variables such as the number of lanes, skewness, the number of thru lanes, the number of approaches and traffic volume were used to develop safety performance function for before the installation period and after the installation period. In before and after the installation scenario, the actual number of red light running and total crashes expected to happen were estimated if the RLC was not installed. The estimated number of crashes were compared with the actual number of crashes occurred at the study intersections after the installation of RLC. The RLC system was considered effective if a decrease in the number of crashes was observed after the installation of RLC. In after installation and after termination scenario, the actual number of red light running and total crashes expected to happen if the RLC was not uninstalled was estimated. The estimated number of crashes were compared with the actual number of crashes occurred at study intersections after the termination of RLC. The RLC system was considered effective if an increase in the number of crashes was observed after the termination of RLC. Rear-end crashes increased by 2.5% after the RLCs were installed while they decreased by 45% after the system was terminated. Sideswipe crashes decreased by 44% after installing the RLCs while they decreased by 50% after the system was terminated. Likewise, angle crashes decreased by 37% after installing the RLCs whereas they decreased by 5% after the system was terminated. Left turn crashes decreased by 2.8% after installing the RLCs while they decreased by 51% after terminating the RLCs. In addition, red light running crashes increased by 21.6% after installing the RLCs while they increased by 10.9% after the system was terminated. Total crashes increased by 16% after the RLCs was installed while they decreased by 55.9% after the system was terminated. After installing RLCs, the number of intersections where sideswipe crashes increased was 17 whereas the number reduced to 5 intersections after terminating RLCs. In the case of left-turn crashes the number of intersections where left-turn crashes increased was 10 intersections whereas the number reduced to 2 intersections after the termination of the RLCs. On the other hand, the number increased from 13 to 24 intersections in the case of rear-end crashes, and 4 to 6 intersections in the case of angle crashes. Empirical Bayes method was used to evaluate the effectiveness of RLC system. Results obtained show that the RLC is not effective in reducing the crashes. Data showed an increase in the number of crashes after the installation of RLCs at the study intersections. After installing the RLCs, red light running crashes increased by 5.7% while they decreased by 1.1% after terminating RLCs. On the other hand, the total number of crashes increased by 4.4% after RLCs were installed whereas they decreased by 2.3% after terminating the RLC. After installing RLCs, the number of intersections where red light running crashes increased was 11 whereas the number reduced to 6 intersections after the termination of the RLCs. Overall a 45% decrease in the performance of number of intersections was observed after the termination of the RLCs. In total crashes scenario, after installing RLCs, the number of intersections where total crashes increased was 9 whereas the number increased to 11 intersections after the termination of the RLCs. Overall a 18% increase in the performance of number of intersections was observed after the termination of RLCs.