Emission Model Sensitivity Analysis: The Value of Smart Phone Weight-Mile Tax Truck Data

This research serves to evaluate the potential use of a system developed by the Oregon Department of Transportation (ODOT) for emission estimates. The data collection system developed by ODOT – Truck Road Use Electronics (TRUE) – includes a smart phone application with a Global Positioning System (GPS) device and microprocessor. Previous research with the TRUE data served to demonstrate its use for important ancillary applications such as highly accurate trip generation rates and mobility performance measures. In addition, it was shown that the TRUE data has strong potential use for safety, accessibility and connectivity, system condition and environmental stewardship performance measures. This new research builds on that past work and evaluates the potential use of the TRUE data for emissions estimates that take into account truck type details, truck weight and detailed speed profiles. A sensitivity analysis using the U.S. Environmental Protection Agency's (EPA) Motor Vehicle Emission Simulator 2010b (MOVES2010b) is performed in order to understand the level of error that might be encountered when such detailed data are not available. The impact of grade on emissions estimates is also considered. Results indicate that TRUE data in integration with Oregon Department of Transportation (ODOT) weight-mile tax (WMT) data will greatly improve the accuracy of emissions estimations at the project and regional level.