Optimal VMS Spacing Strategy with Considering Traffic Information Update Interval

As a collective device of traffic information provision, VMS (Variable Message Sign) is becoming more and more popular and common for road users in Korea. Placed generally in front of diverging points, it offers traffic information for various alternative routes. The selection of VMS locations are one of the concern for ITS deploying group is faced with. This paper focuses on finding out the optimal installation distances between VMS while considering both information demand and information supply. A sample network has been employed and an actual spot decision was made by using IDAS and B/C ratio as a measure of effectiveness. As a result, the distance of three to five kilometers was identified as the most useful distance between VMSs. Some limitations and future directions have also been presented.