The purpose of the research is to determine the benefits of ramp meters in the Milwaukee area freeway system, to determine underlying relationships that permit evaluation of new ramp meters or ramp meter systems elsewhere, and to develop a coherent framework for performing evaluation of ramp meter effectiveness on a whole system. Part 1 focused on documenting diversions as a result of the meters and evaluating three simulation software packages. Part 2 analyzed the traffic operations impact of six new ramp meters for a freeway stretch that already had six ramp meters in place. Investigators for Part 1 found statistically significant diversions away from the highway as a result of the metering and noted the most convincing simulations using the Paramics software package. Results of Part 2 include improved average corridor speed and a 13% crash reduction as a result of the new meters. Part 2 concentrates on the traffic operations affect six new ramp meters had on the 14-mile long corridor where six ramp meters were already operational. A crash rate comparison was performed between the periods the corridor operated without and with the six new ramp meters. Metered on-ramp queue length and delay information is presented in Appendix A; details of the operation of a metered on-ramp as well as mainline speed, occupancy and volume information in the vicinity of the ramp are presented in Appendix B. Average corridor speeds improved when the new ramp meters were operational. Vehicle-hours of travel were lower during the more congested afternoon peak period. It is suggested that fine-tuning of ramp metering parameters is very likely to result in additional benefits for the corridor. Crash rates during ramp metering hours were lower by 13% with the new ramp meters operational. For the complete report see http://www.dot.wisconsin.gov/library/research/docs/finalreports/45-17ra…
Abstract