Quantifying the Impact of Pace-Maker Light on Traffic Capacity Considering Longitudinal Variations

Abstract

Pace Maker Light (PML) is considered as one of solutions for improving traffic capacity at sags of expressways, and the number of its installation has been increased. However, the condition that PML works best is uncovered, and, in fact, its impact on traffic capacity has not been quantitatively identified. It is not enough to compare the traffic capacity before and after the installation of PML for evaluating its impact, because the value of traffic capacity varies longitudinally and periodically. In this study, we focus on the percentile value of traffic breakdown probability and traffic volume after breakdown, and analyze their longitudinal variation during 2010 to 2016 by employing dynamic linear model. As a result, it is revealed that i) 5 percentile value of breakdown probability has reduced more than 15 % since 2010 till 2016 and the periodical factors occupy around 10%, ii) PML significantly contributes to improve the value of traffic capacity, and the reliability of traffic capacity as well.