Impact of Electronic Toll Collection and Electronic Screening on Heavy-Duty Vehicle Emissions

Abstract

The proliferation of electronic toll collection (ETC) mechanisms such as E-ZPass has a positive effect in reducing automobile emissions at toll plazas because of decreased acceleration, deceleration, and idling events. Modeling tools such as the California Modal Emissions Model can be used to measure the emissions impacts of ETC and other electronic screening (e-screening) facilities only on light-duty gasoline-fueled vehicle operations. No such tools exist for modeling of the emissions impacts of ETC and e-screening facilities on heavy-duty vehicle operations. This paper presents a speed profile discretization (SPD) technique for modeling emissions at ETC and e-screening facilities. The SPD technique is based on the MOBILE6.2 method of representing vehicle miles of travel in various speed bins. The technique defines an emissions influence zone within which speed profiles are altered and further determine vehicle emissions. With this technique, the emissions impacts of heavy-duty trucks at the toll collection plaza on the George Washington Bridge in New York City are estimated. The current mix of cash and E-ZPass transactions on the George Washington Bridge are shown to reduce emissions of volatile organic compounds (VOCs), hydrocarbons (HCs), and oxides of nitrogen (NOx) within the emissions influence zone. The degree of reduction is dependent on the speed with which E-ZPass vehicles are processed. If E-ZPass vehicles are processed at no more than 10 mph, reductions in VOC, CO, and NOx emissions are estimated to be 30.8%, 23.5%, and 5.8%, respectively. Results indicate that if E-ZPass allows vehicles to be processed at 20 mph, reductions in VOC emissions due to truck traffic alone could be as high as 50%.