Simultaneous Measurement of On-Road Vehicle Emissions and Traffic Flow Using Remote Sensing and an Area-Wide Detector

The goal of this project, sponsored by the Transportation Research Board and conducted jointly by NC State University, the National Institute for Statistical Sciences, and the Division of Air Quality of the NC Dept. of Environmental and Natural Resources, is to demonstrate a methodology for development of empirical emissions models based upon observable traffic variables. On-road emissions of carbon monoxide (CO) and hydrocarbons (HC) were measured at two sites in the Research Triangle Park area using a remote sensing device (RSD). Individual vehicle speed, acceleration and license numbers were also collected using the RSD. Traffic parameters for individual vehicles (e.g., speed, headway, vehicle type) were simultaneously measured using a video-based area-wide traffic detection system known as Mobilizer. For approximately 7,000 light duty vehicles, valid measurements from both the RSD and Mobilizer were obtained. License plate data were used to obtain vehicle registration data, which assists in more detailed classification of vehicle type as well as other useful data such as vehicle model years. Vehicles were also classified as to whether they were in a platoon and, if so, their position in the platoon. This paper focuses on the deployment of the RSD and Mobilizer, an overview of the methodology for developing a combined data set, and preliminary results from field measurements at one site.