The objectives of this study were to define a performance measure(s) that could be used to show congestion levels on critical corridors throughout Virginia and to develop a method to select and calculate performance measures to quantify congestion in a transportation system. Such measures could provide benchmarks or base values of congestion to aid in measuring changes in the performance of the highway system. A general method was developed to monitor congestion using performance measures and the intelligent transportation system information from the Virginia Smart Travel Lab. Two performance measures were selected for investigation: total delay and the buffer index. These performance measures were applied to evaluate congestion levels on the roadways in the Hampton Roads region of Virginia. Each measure shows a different dimension of congestion. In general, total delay is better suited for use by transportation professionals because it is given in units of vehicle-minutes and applies to all vehicles on a segment of roadway. The buffer index is suitable for use by the public because it addresses individual vehicle trip travel time and can be used for trip planning. The buffer index is also important to transportation professionals as a measure of variability. This research provides information on the changing state of congestion on selected corridors throughout Virginia. It will help the Virginia Department of Transportation determine the best ways to measure congestion and provide a way to compare congestion over periods of time to ascertain if the delay has grown worse or improved. This research can also help establish a benchmark for traveler delay on Virginia's roadways.
Abstract