Document Type


Date of Award



College of Science, Engineering, and Technology (COSET)

Degree Name

MS in Transportation Planning & Management

First Advisor

Professor Lei Yu


Truck idling contributes significantly to both energy consumption and au emissions. The U.S. EPA (Environmental Protection Agency) estimates that idling trucks consume, annually, over 950 million gallons of diesel fuel, and emit over 10 million tons of carbon dioxide (C02) and approximately 200,000 tons of oxides of nitrogen (NOx). Truck idling emission is a complicated phenomenon that must be considered independently of other mobile emissions. Various problems are associated with engine idling, including pollutant emissions, noise pollution, driver discomfort, and unnecessary fuel and maintenance costs. The U.S. May 2001 National Energy Policy tasks to reduce truck idling, through such initiatives as EPA's comprehensive program that issues grants, implements demonstration projects, and most importantly, closely examines idling fuel consumption and exhaust emissions. Recently, EPA and other organizations and institutions have examined idling for brief as well as long periods of time in divers groups of heavy-duty trucks under various engine speeds, ambient temperatures, and 1 2 accessory loads. Even so, the operation of engine idling after different driving conditions has not been fully examined. In this research, an attempt is made to measure actual idling emissions from truck tailpipes and to relate measured emissions to altered pre-testing .driving conditions. The On-Board Emission Monitoring system (OEM-2I00) is employed 􁪽!􁪽 testing. This equipment determines the concentration and masses of HC, CO, CO2, O;,􁪽 and NOx in the exhaust gas on a second-by-second basis by a functional equivalent of a repair-grade dual five-gas analyzer subsystem. Altered driving circumstances considered during truck idling tests include cold starts and hot starts, different distances and durations of driving before the tests, different roadway facility types used while driving, different durations of idling tests, etc. Measured emissions under all the different pre-testing driving conditions are compared and necessary conclusions are made. In addition, measured idling emissions are compared with emissions estimated by the emission estimation model MOBILE6.2 for the particular testing truck.