Understanding Emissions from Extended Idling by Trucks

Focus Area

Air Quality


Air Quality






2-3 years

Research Idea Scope

The objectives of this research will be to better understand the contribution of extended idling (hoteling) by heavy-duty diesel trucks to state and local emissions inventories, and to assist local agencies in improving their estimates of emissions from truck hoteling. Research methods may include field data collection (e.g., truck stop surveys), analysis of telematics data purchased or otherwise acquired that includes information on engine status as well as vehicle location, and/or other methods. The goal is to better understand and quantify the activity patterns of long-haul trucks (locations and time spent hoteling) and the use of different operating modes (engine idle, auxiliary power unit, electrification) to provide power during hoteling periods. Consideration of how these factors vary by climate and season, infrastructure (e.g., availability of truck parking areas and electrical hook-ups), and truck population characteristics (traffic volume, vehicle ages, etc.) will be important.

Urgency and Payoff

Heavy duty diesel vehicles account for a substantial fraction of emissions in state and local mobile source inventories, especially particulate matter (PM) and oxides of nitrogen (NOx). According to the MOVES model, a significant (and increasing) fraction of heavy-duty vehicle emissions is estimated to come from extended idling (hoteling) by long-haul trucks. A sensitivity analysis conducted for NCHRP 08-101 (Enhanced Truck Data for Emissions Modeling) found that varying the hoteling inputs could have an “extremely high” effect on total truck emissions (over 50 percent). The research also found, by analyzing national data purchased from a telematics data provider, that the default hoteling values in the MOVES model (based on the Federal Motor Carrier Safety Administration hours-of-service rule) were potentially overestimating hoteling emissions by at least an order of magnitude. The national sample data obtained could not be used to examine localized hoteling activity, however. Some local studies on truck extended idling have been conducted, but mainly in Texas, including research in progress for the Texas Commission on Environmental Quality. Research is urgently needed to better understand the contribution of truck hoteling to emissions inventories in other parts of the country and to assist state and local agencies in refining their mobile source emissions inventories.

Suggested By

Chris Porter Cambridge Systematics, Inc. 781-539-6723

[email protected]