Evaluation and Improvement of the Stratified Ramp Metering Algorithm through Microscopic Simulation
Principal Investigator:
Panos Michalopoulos, Professor, Civil Engineering
Project Summary:
This research is in response to a request for low-cost innovative solutions for evaluating and improving the current and future ramp-metering strategies in the Twin Cities. This is a continuation of a recently concluded project in which the previous Mn/DOT ramp control algorithm was successfully evaluated for two Twin Cities freeways. In this previous project, it was demonstrated that evaluation results through simulation are similar if not superior in content and accuracy to the ones reached by before-and-after studies. This project goes beyond evaluation and seeks to find a methodology for optimizing the new ramp-metering algorithm quickly and efficiently prior to field deployment. In the first year, the new stratified metering algorithm will be evaluated and compared with the old algorithm, a simple control plan (i.e., fixed-time metering), as well as with a no-control case. Detailed statistics will evaluate all aspects of the new algorithm?s operation including queue formation and bottleneck operation, as well as long and short trip travel times. In addition, a sensitivity analysis will be conducted in order to understand the behavior of the new control algorithm with respect to changes in traffic demand, occurrence of traffic incidents, detector malfunctions, inclement weather conditions, and changes in the algorithm's own parameters. If successful, further plans include expansion of the sensitivity analysis to include the impacts of traveler information on the control strategy. Based on the knowledge acquired through the sensitivity analysis, fine-tuning of the algorithm parameters will take place through both manual search and optimization methods. Finally, researchers will explore improvements to the algorithm structure in order to better take into account queue and other traffic pattern measurements.
Sponsors:
- Mn/DOT Guidestar
Project Details:
- Start date: 04/2004
- Project Status: Completed
- Research Area: Transportation Safety and Traffic Flow