Benefit

The CORSIM simulation model has been used to estimate ramp metering speed improvements at the merge influence area under different ramp and mainline volumes, acceleration lane lengths, and number of lanes conditions, and the simulated outputs show that the average speeds at the merge influence areas increase when on-ramp junctions are metered, and that the increase is most prevalent under high traffic volumes, short acceleration lane, and low number of mainline lanes.


13-18 January 2002
United States


Summary Information

Ramp metering is an effective control strategy for preventing the formation of bottlenecks at critical ramp junctions. The most basic form of metering strategies is simple ramp metering. It aims to minimize the turbulence of flow on the freeway caused by platoons of merging vehicles.

The current Highway Capacity Manual (HCM) procedure for the analysis of on-ramp junctions does not consider the effect of ramp metering and is, thus, unable to predict the average speeds at metered on-ramp junctions. This paper describes an effort to quantify the speed improvements as a result of simple ramp metering under various traffic and geometric conditions. The results can be used as supplements to the current HCM procedure to adjust for the effect of simple ramp metering at on-ramp junctions. Simulation models (CORSIM) were developed to estimate speed improvements at the merge influence area under different ramp and mainline volumes, acceleration lane lengths, and number of lanes conditions. The simulated outputs show that the average speeds at the merge influence areas, as expected, increase when on-ramp junctions are metered, that the increase is most prevalent under high traffic volumes, short acceleration lane, and low number of mainline lanes. A set of look-up tables for predicting speed improvements at on-ramp junctions due to simple ramp metering was developed. These tables can serve as supplements to the current HCM procedure to adjust for the effect of metering on average speed. Although simulated data shows logical relationships among all the variables considered, further studies might attempt to validate the simulated results with field data and to fine-tune the results.

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Source

Using Simulation to Estimate Speed Improvements from Simple Ramp Metering at On-Ramp Junctions

Author: Lahiri, Sanhita, et al.

Published By: Paper presented at the 81st Annual Transportation Research Board Meeting. Washington, District of Columbia

Source Date: 13-18 January 2002


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Goal Areas

Mobility

Typical Deployment Locations

Metropolitan Areas

Keywords

ramp meters

Benefit ID: 2002-00249