Ramp Metering Impact Study with Potential Regional Deployment Within the Dallas- Fort Worth Ozone Nonattainment Area

There is an increasing interest by public officials in the use of ramp metering for congestion mitigation at various freeway locations in the Dallas-Fort Worth (DFW) metroplex. DFW is currently in nonattainment for ground-level ozone, and transportation improvements in the area are subject to transportation conformity process. This project used dynamic traffic assignment and microscopic simulation models to evaluate the impacts of ramp metering on traffic conditions in two DFW corridors, selected using existing vehicle probe data. The project also assessed impacts of ramp metering on air quality by applying DFW-specific emissions rates to outputs from the simulation models. Results show that ramp metering can help improve operations of congested freeways without adversely affecting air quality in corridors where the cause of congestion is primarily from these ramps. Ramp metering with queue flush operation is the recommended strategy.