Citation

Li Y, Wang H, Wang W, Liu S, Xiang Y. Traffic Injury Prev. 2016; 17(6): 597-603.

Affiliation

School of civil engineering and architecture, Nanchang Hangkong University , Fenghenan Avenue #696, Nanchang , P. R. China , 330063 , Tel: +86-13732976063 ; Email: xiangyun927@163.com.

Copyright

(Copyright © 2016, Informa - Taylor and Francis Group)

DOI

10.1080/15389588.2015.1121384

PMID

26761633

Abstract

OBJECTIVE: Adaptive cruise control (ACC) has been investigated recently to explore ways to increase traffic capacity, stabilize traffic flow, and improve traffic safety. However, researchers seldom have studied the integration of ACC and roadside control methods such as the variable speed limit (VSL) to improve safety. The primary objective of this study was to develop an infrastructure-to-vehicle (I2V) integrated system that incorporated both ACC and VSL to reduce rear-end collision risks on freeways.

METHODS: The Intelligent Driver Model was firstly modified to simulate ACC behavior, and then the VSL strategy used in this paper was introduced. Next, the I2V system was proposed to integrate the two advanced techniques, ACC and VSL. Four scenarios of No-control, VSL-only, ACC-only, and the I2V system were tested in simulation experiments. Time exposed time-to collision (TET) and the time integrated time-to collision (TIT), two surrogate safety measures derived from time-to-collision (TTC), were used to evaluate safety issues associated with rear-end collisions. The total travel times of each scenario also were compared.

RESULTS: The simulation results indicated that both the VSL-only and ACC-only methods had a positive impact on reducing the TET and TIT values (reduced by 53.0% and 58.6%, and 59.0% and 65.3%, respectively). The I2V system combined the advantages of both ACC and VSL to achieve the most safety benefits (reduced by 71.5% and 77.3%, respectively). The sensitivity analysis of TTC threshold also shown that the I2V system obtained the largest safety benefits with all the TTC threshold values. The impact of different market penetration rates of ACC vehicles in I2V system indicated that safety benefits increase with the increase of ACC proportions.

CONCLUSIONS: Compared with VSL-only and ACC-only scenarios, this integrated I2V system is more effective on reducing rear-end collision risks. The findings of this study provide useful information for traffic agencies to implement novel techniques to improve safety on freeways.

Language: en