Acquisition of relative vehicle trajectories to facilitate freeway merging using DSRC based V2V communication

For the anticipated benefits of connected vehicle technology, Intelligent Transportation Systems Joint Program Office (ITSJPO) of the US Department of Transportation continues to emphasize the need for having Dedicated Short Range Communication (DSRC) based vehicle to vehicle (V2V) and/or vehicle to infrastructure (V2I) communication to enhance driver safety and traffic mobility. To take full advantage of connected vehicle technology in most safety applications, precise vehicle positioning information is neeeded in addition to V2V communication. Although, there are many techniques including vision or sensor based systems and differential GPS receivers, which can obtain precise absolute position of a vehicle at the expense of cost and complexity, some critical safety applications such as merge assist or lane change assist systems require only relative positions of surrounding vehicles with lane level resolution so a given vehicle can differentiate the vehicles on its own lane from the vehicles on adjacent lanes. We have adopted a simple approach to acquire accurate relative trajectories of surrounding vehicles using standard GPS receviers and DSRC based V2V communication. Using this approach, we have conducted field tests to successfully acquire relative trajectories of vehicles travelling on multiple lanes towards a merging junction with an accuracy of ±0.5m. The achieved accuracy level in relative trajectory was sufficient to differentiate vehicles travelling on adjacent lanes of a multiple-lane freeway.