Idle Reduction Research and Development
The U.S. Department of Energy (DOE) is leading research and development on technologies that reduce the need for vehicle idling while maintaining or improving driver comfort. Some of these research efforts are described below.
Comfort in the Cab
DOE leads idle reduction research projects, such as the CoolCab project, which used infrared images to evaluate insulation and heat transfer in truck cabs. For more information, see Reducing Thermal Loads in Long-Haul Trucks.
Medium-Duty Truck Cycle Project
To quantify the extent of workday idling by medium-duty vehicles, researchers at Oak Ridge National Laboratory are collecting data on approximately 80 duty-cycle performance indicators from real-world vehicles in a variety of industries. The data acquisition systems actively capture details on fuel consumption, brake and tire performance, speed, and idling, as well as external conditions that impact duty cycle, such as precipitation, wind, road grade, and weight. Data collected are being used to support modeling and studies of fuel efficiency evaluation of tires, payload weight, speed, and driver style.
Estimating Energy Use and Emissions of Idling Reduction Options for Heavy-Duty Diesel Trucks
Pollution and energy analyses of different idle reduction (IR) technologies previously have been limited to localized vehicle emissions, and have neglected upstream energy use and regional emissions. Researchers at Argonne National Laboratory analyzed the full-fuel-cycle effects of current approaches. Researchers compared emissions, energy use, and proximity to urban populations for nine alternatives, including idling, electrified parking spaces, auxiliary power units, and several combinations of these. They compared effects for the United States and seven states. The research showed that it is important to consider the full-fuel-cycle impacts during any technology comparison, because upstream impacts can significantly alter the relative positions of the options.
In-Cab Air Quality of Trucks Air-Conditioned at Electrified Truck Stops
Different methods of air conditioning a heavy-duty truck cab during rest stops produce different air quality outcomes inside the cab. Researchers at Oak Ridge National Laboratory compared the effects of using different air-conditioning methods at a Texas truck stop with electrified parking spaces. They found that using the electrified parking space power for air conditioning provided better in-cab air quality results for nitrogen oxide (NOx), carbon monoxide (CO), and particulate matter (PM) than did an idling vehicle. Using power from auxiliary power units (APUs, which are small diesel engines mounted on the exterior of the cab) for air conditioning emitted lower levels of NOx, CO, PM, and total hydrocarbons than did idling vehicles. The study did not consider emissions produced by generating the electricity that powered the electrified parking spaces, since those occur in a different location.
Climate control is the primary reason truck drivers keep their engines running during rest periods. In warm weather, engine idling powers the air conditioner to offset heat from the sun and from the truck's engine and exhaust. In cold weather, idling heats the cab, protecting the driver from low outside air temperatures. Truckers experience a wide range of hot and cold conditions throughout their day and year. Some idle reduction systems introduced in recent years have lacked the capacity to maintain driver comfort under these varying thermal conditions. DOE and the National Renewable Energy Laboratory (NREL) initiated the CoolCab project to improve the effectiveness of idle reduction systems.
The CoolCab project partnered with companies such as Schneider National, Volvo, and International Truck and Engine Corporation to quantify truck thermal loads, identify areas for improved thermal management, and evaluate thermal management technologies. An evaluation of the thermal load reduction benefits of privacy curtains and window coverings is detailed in the paper Thermal Load Reduction of Truck Tractor Sleeper Cabins. Ongoing CoolCab work includes developing computer models of truck cab heat transfer and climate control and working with truck and idle reduction technology manufacturers to define idle reduction system requirements.
Idle Reduction Technology Demonstrations
DOE initiated a study of diesel truck engine idle reduction technologies in 2002 through the Advanced Vehicle Testing Activity (AVTA). The study identified several barriers to widespread use of existing idle reduction technologies, including initial cost, driver education and receptiveness, reliability, and maintenance considerations. The study results were used to develop a plan to implement idle reduction technologies. As part of this study, AVTA sponsored four idle reduction demonstration projects, which consist of teams of a truck fleet, truck manufacturer, and idle reduction technology manufacturer. See the project details and results in the 2007-2008 Final Status Report.
Other Government-Sponsored Idle Reduction Activities
The U.S. Environmental Protection Agency's (EPA's) SmartWay Transport Partnership sponsors idle reduction projects. EPA's Clean School Bus USA program pursues efforts to reduce children's exposure to diesel exhaust caused by school buses. DOE's Clean Cities Program lists funding sources for transportation projects, including idle reduction. The National Idling Reduction Network News is also an excellent source of information on idle reduction developments and funding opportunities. The Texas Transportation Institute's Web page, National Deployment Strategy for Truck Stop Electrification, provides several reports and tools developed with funding from the EPA.