Optimum Method of Loop Detector Location Density for Expressway based on Travel Time Estimation

With the urgent demand for real-time traffic information in Intelligent Transportation System, the high-density installation of detectors has been adopted, while the amount of investment has been sharply increased. So optimum detector location density is necessary. In this paper, the optimum method based on travel time estimation has been expounded. The major conclusions could be summarized as follows: considering the appropriate estimation error for travel time and reasonable investment, the space between detectors has a suitable bound and the high-density installation of detectors is not always good for ITS system. The method for selecting suitable bound discussed in the paper could be introduced to confirm detector density and detector amount in practical applications, then according to this bound the optimum detector location density can be achieved.