Variable speed limit method of mountainous expressway based on traffic conflict Index(PDF)
长安大学学报（自然科学版）[ISSN:1006-6977/CN:61-1281/TN]
- Issue:
- 2018年05期
- Page:
- 154-161
- Research Field:
- 交通工程
- Publishing date:
Info
- Title:
- Variable speed limit method of mountainous expressway based on traffic conflict Index
- Author(s):
- LI Chuanhua1; WU Hao2; SUN Yifan2
-
- Keywords:
- traffic engineering; traffic safety; variable speed limit; METANET; traffic conflict; mountainous expressway
- PACS:
- -
- DOI:
- -
- Abstract:
- In view of the lack of research on the control effect of the VSL system in a traffic flow stability layer, METANET macro traffic flow model was proposed，with the purpose of improving traffic safety on mountainous highways by minimizing the risk of traffic conflicts and decreasing the speed difference in adjacent road sections. The variable speed limit method was used to establish a multitarget speed limit optimization model for mountainous highways and develop a simulation environment for testing different conditions. The impact of the variable speed limit control system on the safety of mountain highway traffic was analyzed. First, a variable rate control strategy was constructed based on the METANET macro traffic flow model, which was then employed to describe traffic flow in the spacetime domain. The ultimate aim was to minimize adjacent section speed differences and thus the total conflict risk. Setting operation efficiency and speed limit range as constraints, the multiobjective optimization variable speed limit model was constructed, and VSL ratios were calculated using the differential evolution algorithm based on swarm intelligence. VB and MATLAB hybrid programming technology was applied, and the speed limit control effect was tested by developing a simulation platform based on traffic flow simulator VISSIM COM. Finally, the simulation model was calibrated with actual mountainous highway traffic flow data, with comprehensive consideration given to factors such as mountain highway traffic characteristics and driver compliance rates. The VISSIM COM/MATLAB simulation environment was used to implement the variable speed limit on the mountain expressway. The results show that speed limit control significantly reduces speed dispersion, resulting in a 30% to 40% reduction of velocity standard deviation， comparison with the case where variable speed limit control is not implemented. This indicates that variable speed limit control can enhance traffic safety in mountainous expressways. 2 tabs, 10 figs, 26 refs.
Last Update: 2018-10-23