Congestion-Responsive On-Ramp Metering : Before and After Studies - Phase 1

016496752016Final Report, 5/12/2015 - 4/30/2016PDFTech ReportUCB-ITS-PRR-2016-01Contract 65A0528 Task 005Congestion management systemsMicroscopic traffic flowRamp meteringTraffic actuated controllersTraffic congestionTraffic dataTraffic simulationTravel timeFreeway ramp metering (RM)Local mainline responsive ramp metering (LMRRM)United States Highway 101United StatesCaliforniaSan Francisco (California)San Francisco Bay AreaCalifornia. Dept. of TransportationMauch, MichaelLu, Xiao-YunSkabardonis, AlexanderUniversity of California, Berkeley. Institute of Transportation StudiesUniversity of California PATH ProgramCalifornia. Dept. of Transportation. Division of Research, Innovation, and System InformationUnited States. Federal Highway AdministrationUS Transportation CollectionThe objective of this project was to develop recommendations toward a statewide policy of congestion responsive freeway ramp metering operation. The research is performed in two phases. In phase 1, alternative ramp metering activation strategies were evaluated through simulation modeling on a real-world freeway test site. In Phase 2, "before" and "after" field data will be collected and analyzed on freeway test sites that have implemented congestion responsive ramp metering activation. This report describes the research performed in Phase 1 of the project. A section of the US-101 freeway in the San Francisco Bay Area was selected as the test site. Field data on traffic and operational characteristics were collected and analyzed to establish the baseline operating conditions at the selected site. Several ramp metering activation strategies were simulated with the VISSIM microscopic model. The analysis of the simulation results showed that 24-7 ramp metering operation could improve the mainline freeway's performance by increasing the average travel speeds, and reducing the overall corridor travel-times at the specific site. No significant changes were found on bottleneck discharge flows and the travel-time reliability