Knowledge Resources

The goal of the Integrated Corridor Management (ICM) initiative is to demonstrate the benefits of integrating ITS technologies on congested corridors. There are an estimated 300 major corridors in the nation that experience congestion, have under-utilized capacity, and manage ITS assets locally as opposed to on a regional, coordinated approach. By integrating ITS assets and implementing ITS strategies regionally, ICM improves mobility and safety. To demonstrate the benefits of ICM, the USDOT sponsored the "ICM - Tools, Strategies and Deployment Support" project. The project evaluated ICM in pioneer sites including U.S. 75, a major corridor in Dallas, Texas.

METHODOLOGY

The analysis, modeling and simulation of Integrated Corridor Management (ICM) strategies on U.S. 75 combined a macroscopic trip table manipulation for determining trip patterns; a mesoscopic analysis for assessing the impact of driver behavior in reaction to ICM strategies; and a mesoscopic traffic simulation model (DIRECT) for reflecting the effects of signal timing. The analysis used 2007 as the model base year, and focused on morning peak periods.

The analysis assessed mobility, reliability and variability, and emissions and fuel consumption. Mobility measures included travel time, delay (defined as the total observed travel time less the travel time under noncongested conditions), and throughput (defined as the number of vehicles and persons per hour by direction). Reliability and variability were calculated from multiple simulated runs under all scenarios. Emissions and fuel consumption were determined by calculating and matching emission rates to reference values in EMFAC, the California Air Resources Board's emission factors model. The values were monetized by applying costs per ton of pollutants released and the purchase price of fuel.

The study evaluated comparative travel time information (pretrip and en-route traveler information); incident signal retiming plans for arterials; incident signal retiming plans for frontage roads (frontage roads run parallel to U.S. 75); light-rail transit (LRT) smart parking system; Red Line capacity increase (Red Line is a LRT); LRT station parking expansion (private parking); and, LRT station parking expansion (valet parking).

FINDINGS

Benefits were savings in travel time, increased travel time reliability, reduced fuel consumption, and reduced emissions production. The extent of the benefits varied by conditions on the corridor. Low demand conditions had benefits of $8.0 million per year largely attributable to saved fuel consumption on the arterial street system from improved signal timing during incident conditions. Medium demand conditions saw a more modest benefit of $2.0 million per year attributable to the disbenefit of diverting traffic from the arterial system onto the freeway system (other than U.S. 75), offset by the benefit of reduced congestion on the arterial system. High demand conditions produced significant improvements systemwide in travel time savings, resulting in a $6.3 million benefit throughout the year.

• The benefit-to-cost ratio over the 10 year life cycle of the project was estimated as 20.4:1.
• Expected annual savings included 740,000 person-hours of travel, a reduction of fuel consumption by 981,000 gallons of fuel, and a reduction of 9,400 tons of vehicular emissions.