Variable Speed Limits Framework on Pilot Study on Alberta Highways

摘要

International research has shown that the Variable Speed Limits (VSL) system is a successful traffic engineering application used to manage traffic conditions during congestion, incidents, road construction, and inclement weather. VSL has been implemented in a number of jurisdictions throughout the world to improve safety and traffic efficiency on the road network. However, there has been limited application of VSL in Canada and the US, primarily owing to the legislative enforcement restrictions. Alberta Transportation (AT) has recognized the need to gain experience in the use of VSL and determine its effectiveness in the Alberta highway environment. This paper is aimed at developing a comprehensive framework for a variable speed limit pilot project and consists of a literature review, development of a project framework, a strategy for evaluating project benefits, and future maintenance and operation requirements. The comprehensive literature review identifies the best practices, guidelines and technical research work on the application and evaluation of VSL in Canada and internationally. Based on the literature review, a site selection criterion is developed which considers collision history, minimum volume threshold, minimum speed, congestion, and weather conditions. A criterion is also developed for reducing the posted speed limited and an evaluation strategy is developed to predict the benefits associated with the speed reduction. A set of recommendations for the maintenance and operations of the VSL system under the pilot project initiative are developed as well as motorist education strategy to increase speed compliance with the VSL zone.