Study Details
Study Title: Safety Evaluation of Variable Speed Limit System in British Columbia
Authors: El Esawey et al.
Publication Date:JAN, 2021
Abstract: Adverse weather conditions create a difficult environment for drivers to navigate safely. This study reports the safety impacts associated with the installation of Variable Speed Limit System (VSLS) on provincial rural highways in in British Columbia (BC), Canada. A VSLS is an advanced intelligent transportation system (ITS) scheme that can be employed to increase the safety level of highway facilities by varying the speed limit according to downstream operational condition and/or current weather conditions. The analysis made use of police-attended serious crashes (i.e. fatal + injury) that took place during winter seasons (October to March). Three winter seasons were available as a before-implementation period, and three winter seasons were available as an after-implementation period. The results of a simple-before-and-after were promising where overall reductions of 35.8% and 36.8% in winter serious collision (WSC) frequency and rate, respectively, were found for the evaluation corridors. An Empirical Bayes (EB) before-and-after safety evaluation was also carried out to ensure that the results are reliable. Safety Performance Functions (SPFs) were developed using data collected at similar sites. The EB analysis showed an overall statistically significant reduction of 34.4% in WSC. An economic assessment of the system was undertaken and the results showed that the benefits of implementing a VSLS exceeded the system cost with an overall benefit-cost (B/C) ratio of 4.3 and a NPV of C$34.41 million. The results of this study may motivate transportation agencies and stakeholders who are interested in pursuing similar systems for mitigating weather-related safety challenges.
Study Citation: El Esawey, M., J. Sengupta, J.E. Babineau, and E. Takyi. "Safety Evaluation of Variable Speed Limit System in British Columbia". Presented at the 100th Annual Meeting of the Transportation Research Board, Paper No. 21-00013, Washington, D.C., (2021).
Study Report: Download the Study Report Document
CMFs Associated With This Study
Category: Advanced technology and ITS
Countermeasure: Install Variable Speed Limit (VSL)
| CMF | CRF(%) | Quality | Crash Type | Crash Severity | Roadway Type | Area Type |
|---|---|---|---|---|---|---|
| 0.693 | 30.7 |  | All | K,A,B,C | All | Rural |
| 0.684 | 31.6 |  | All | K,A,B,C | All | Rural |
