Ramp Metering: A Proven, Effective Strategy

2014PDFBooklet/PamphletFHWA-HOP-14-021Ramp meteringTraffic volumeFreeway operationsUnited StatesUnited States. Federal Highway Administration. Office of OperationsUnited States. Federal Highway Administration. Office of OperationsFederal Highway AdministrationRamp metering is a strategy used to regulate the volume of vehicles entering a freeway at a given time thereby seeking optimal freeway operations. Access to the freeway is controlled using a traffic signal that is powered by an algorithm that uses real-time system traffic data to determine the rate at which vehicles should enter the freeway. This breaks up the platoons of vehicles attempting to merge onto the mainline. Vehicles already on the mainline will not need to reduce their speed as much due to the spacing of the entering vehicles. This document briefly explores the benefits, common challenges, keys for successful deployment, public outreach, and performance measurements of ramp metering. Case studies are also included.83