Algorithm for variable message sign location on urban traffic network considering road attributions

Variable message sign (VMS) is an important tool for traffic guidance. However, the effectiveness of VMS largely depends on the number and location of installation in road network. In practice, VMS location is always based on the managers´ experiences and subjective judgments, without sufficient theoretical support. This paper presents an algorithm for VMS location through road traffic network in which the idea of backtracking is used. The location order can be obtained by scanning the four multi-level traffic-guidance attributions on each road. These four attributions include road grade, traffic flow, and information intensity and information attenuation. In the proposed algorithm, the remaining roads will be scanned by using lower-level attribution or rescanned by using the same upper-level attribution after one attribution has been checked for one road. In this algorithm, not only the static factors related to traffic information are taken into account, but also the dynamic one like information attenuation is considered. Finally, a practical example of the algorithm is analyzed and verified.