01764259

Component

https://annualmeeting.myt...nlineProgram/Details/15793

Adverse weather conditions create a difficult environment for drivers to navigate safely. Reducing weather-related collisions is a priority in British Columbia (BC), Canada. This study reports the safety impacts associated with the installation of Variable Speed Limit System (VSLS) on provincial rural highways in BC. 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.

This paper was sponsored by TRB committee ACS20 Standing Committee on Safety Performance Analysis.

TRBAM-21-00013

English

18p

2021

Transportation Research Board 100th Annual Meeting

Digital/other

Figures; References; Tables

Bayes' theorem; Before and after studies; Crash data; Economic impacts; Highway safety; Rural highways; Traffic crashes; Variable speed limits; Weather conditions; Winter

British Columbia

Highways; Operations and Traffic Management; Planning and Forecasting; Safety and Human Factors

Transportation Research Board Annual Meeting 2021 Paper #TRBAM-21-00013

TRIS, TRB, ATRI

Dec 23 2020 11:23AM