SIMULATION OF DETECTOR LOCATIONS ON AN ARTERIAL STREET MANAGEMENT SYSTEM

The research presented in this paper used computer simulation to investigate the relationship between detector location and the ability of a system to monitor traffic characteristics (flow, speed, occupancy) and from them estimate link travel characteristics (link speed, travel time, intersection delay). A 3 mi (4.8 km) section of roadway in the Phoenix metropolitan area was simulated using the program CORSIM. Four detector locations within each major link were analyzed. One detector location was downstream of a major intersection; the other three locations were upstream of a major intersection. Statistical techniques, in the form of regression analysis, were used to evaluate the various dependent and independent variables. Results of the analysis indicated the link travel characteristics are unique to each link on the network. Of the variables examined, there was no one singular relationship that can be used to predict link travel characteristics. Further, there was no particular detector location that proved to be superior to all other detector locations. Detectors located downstream of major intersections can use traffic flow to predict link travel time with reasonable accuracy. Detectors located upstream of major intersections can use spot speed or detector occupancy to predict link travel speed with reasonable accuracy. The predictive capability applies to recurring congestion but does not apply to incident situations. The spacing of detectors can be critical to the operation of a system. The research showed that detector data obtained on one link could not accurately predict link travel characteristics on an adjacent link.