Research on Installation Site of Loop Detectors for Link Travel Time Estimation

The installation site of loop detectors directly influences the quantity and quality of information detected and processed. Searching appropriate installation sites not only contributes to realizing more accurate traffic estimation, but also is able to accomplish a better cost-effectiveness. In this paper, three positions were chosen as the loop location alternative sites: (1) site beside upstream intersection; (2) site beside downstream intersection; and (3) sites in the middle of the link. By comparing their average relative errors (AREs) and relative AREs distribution of link travel time, a better loop location site could be determined on the basis of definition of link travel time in Highway Capacity Manual (HCM) 2000. Moreover, different volumes in road network were also considered to test the outcomes. VISSIM simulation was used to build the road network in order to detect all the traffic data. The purpose of this paper is to seek superior locations of loop detectors for dynamic link travel time estimation on urban roads.