Variable Speed Limits: Strategies to Improve Safety and Traffic Parameters for a Bottleneck

  • M. Z. Hasanpour Transportation Research Institute, Housing & Urban Development, Research Center Tehran, Iran
  • M. R. Ahadi Transportation Research Institute, Housing & Urban Development, Research Center Tehran, Iran
  • A. S. Moghadam Transportation Planning, Shomal University, Iran
  • G. A. Behzadi Transportation Research Institute, Housing & Urban Development Research Center Tehran, Iran
Volume: 7 | Issue: 2 | Pages: 1535-1539 | April 2017 |


The primary purpose of the speed limit system is to enforce reasonable and safe speed. To reduce secondary problems such as accidents and queuing, Variable Speed Limits (VSL) has been suggested. In this paper VSL is used to better safety and traffic parameters. Traffic parameters including speed, queue length and stopping time have been pondering. For VLS, an optimization decision tree algorithm with the function of microscopic simulation was used. The results in case of sub saturated, saturated and supersaturated at a bottleneck are examined and compared with the Allaby logic tree. The results show that the proposed decision tree shows an improved performance in terms of safety and comfort along the highway. The VSL pilot project is part of the Road Safety Improvement Program included in Iran’s road safety action plan that is in the research process in the BHRC Research Institute, Road and Housing & Urban Development Research that is planned for next 10-year Transportation safety view Plan.

Keywords: variable speed limits, decision trees, safety, transportation, highway, traffic


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