Traffic Impedance Estimation Driven by Trajectories for Urban Roads

Traffic impedance has attracted massive attention. The accurate estimation for the travel time along a specific road segment is of great significance for public traffic assignment and personal travel planning. The representative impedance function requires the traffic flow on corresponding road segments as inputs. However, traffic monitoring systems available cover quite limited number of roads in urban environment, which making it impossible for unmonitored roads' impedance estimation. Fortunately, the ubiquitous trajectories generated by the probe vehicles on the urban roads just make up for this defect, thus the main challenge is how to utilize trajectories to estimate road traffic impedance. In this paper, we propose a speed-based impedance function (SIF) for urban roads with consideration of road intersection. We divide the travel time of a road into the free flow driving part and the road intersection queuing part. Inspired by the impedance function of BPR (Bureau of Public Roads), we apply its simple deformation to the driving part. For the queuing part, we propose a novel simple speed-based computing model. Evaluation on several urban roads with real trajectory data demonstrates the effectiveness of our proposed method.