Placement of Roadside Equipment in Connected Vehicle Environment for Travel Time Estimation

Vehicle-to-infrastructure (VTI) communication technology offers great potential to improve safety and mobility in transportation systems. One application of VTI communication to mobility is the measurement of travel time in an urban road network. The presence of traffic control at intersections in an urban network makes it challenging for traditional traffic-monitoring methods to provide accurate travel times. The use of several new technologies (e.g., Bluetooth) has been proposed to alleviate this problem. One of the features of the VTI communication technology is probe vehicle data collection, in which vehicles collect information on, for example, their location and speed. The speed information can be used for travel time estimation. This paper proposes a methodology for determining the optimal placement of roadside equipment (RSE) for travel time estimation in a VTI communication environment. A connected vehicle simulation test bed of Boise, Idaho, was developed in VISSIM traffic simulation software according to the SAEJ2735 standard. A hybrid performance measure, the network coverage index, which combines travel time error and the number of links for which travel times are available, is proposed. A genetic algorithm-based solution method was implemented in conjunction with the simulation test bed to determine the optimal placement of different RSE deployments. The results indicate that the proposed methodology is capable of optimization of RSE locations in a VTI communication environment Sensitivity analysis was also conducted by the use of various market penetration rates and travel time estimation intervals. The results indicate that higher penetration rates and larger estimation intervals produce better coverage index values.