The goad of this project is to produce an inexpensive, automated process for vehicle reidentification and travel time measurement using existing paired loop detector speed traps. By observing a sequence of vehicles at an upstream location and reidentification the vehicle at a downstream location, travel time can be measured directly. Travel time is a key parameter for ATIS applications and sudden changes in link travel time may indicate an incident. A pilot study is presented showing the feasibility of vehicle reidentification from vehicle lengths measured over a large separaion (i.e., distances of one mile were used in the pilot study described herein), in the presence of measurement noise, congestion and lane changes. The pilot study illustrated the basic components of the proposed travel time measurement system. The pilot study also revealed calibration problems in the FSP database: the speed trap clocks are not calibrated with eath other nor with the probe vehicles. In conjuction with developing the travel time measurement system, the proposal calls for recalibrating the clock offsets in the FSP database for "ground truth" travel times via the probe vehicles and publishing the new clock offsets for other reseachers working with the FSP database. The proposal will develop incident detection strategies based on the travel time data and investigate the usefulness of supplying measured travel time information to drivers for ATIS applications. Upon completion of the proposed study, the reidentification system could be implemented in the near-term.
Abstract