Evaluation of Cell Phone Traffic Data in Minnesota

For decades, traffic conditions have been measured using aggregated point measurements from loop detectors. However, new technologies have become available recently that can assess traffic conditions by tracking vehicle trajectories and travel times. Among these new technologies is cell phone tracking, a concept that has received strong interest from the transportation community. AirSage, Inc., a private firm in the United States, has constructed a proprietary system that, using the Sprint PCS network, can track cell phone movements in Minneapolis, Minnesota, and deliver travel times for most of the urban roads, including both limited access freeways and signalized arterials. A University of Minnesota research team was consulted to evaluate the system's travel times against measured conditions and assess the level of accuracy and reliability of the technology through statistical analysis. The system's performance during its first-stage deployment in May and early June of 2007 was evaluated, including the system's accuracy on a limited access freeway and a signalized arterial during the peak hours over a 16-day period. The technology produced results with varied accuracies. Whether this system would produce acceptable margins of error for speeds and travel times depends on the guidelines set forth by interested transportation agencies.