The Texas A&M Transportation Institute (TTI) worked with the Federal Motor Carrier Safety Administration (FMCSA) on a study to better understand truck drivers’ exposure to diesel exhaust.
There are over 3.5 million truck drivers in the United States, a large proportion of whom undertake long-haul operations. These drivers are on the road for long periods of time, during which every 11 hours of driving is followed by a mandated rest period of 10 hours. Drivers often spend these rest periods parked at truck stops or rest areas, with the truck engine idling to provide air conditioning. This lifestyle can potentially expose truck drivers to large amounts of diesel exhaust. This can cause driver fatigue and reduced alertness in the short term, and can increase the risk of heart disease, lung cancer and other illnesses in the long term. FMCSA was particularly interested in investigating exposure to fine particulate matter (PM2.5), and the potential impact of idle reduction technologies (IRTs) in reducing driver exposure.
“Taking on this project allowed us to support FMCSA and the trucking industry and explore an issue that affects many—if not all long-haul truck drivers,” said Joe Zietsman, Principal Investigator on the project and division head for TTI’s Environment and Air Quality Division. “IRTs have the potential to reduce exposure to emissions and create a safer environment for U.S. truck drivers.”
The project team was comprised of a collaboration of researchers from TTI, Georgia Tech and The University of Michigan Transportation Research Institute (UMTRI). This project focused on the impact of diesel-powered IRTs on truck drivers’ in-cab exposure to particulate matter during driver rest periods.
The study involved field data collection at truck stops in California, Georgia, and Texas, followed by laboratory testing on a sample of trucks in a controlled test chamber.
During the laboratory testing, researchers looked at the impact different technologies have in-cab PM2.5 levels during long duration idling events. Testing was conducted at TTI’s Environmental and Emissions Research Facility (EERF), an environmentally controlled test chamber capable of controlling temperature, humidity, solar loading, and wind. By testing the trucks in the EERF, the research team was able to replicate field conditions in a controlled environment. The test cases included trucks parked with the engine turned off, idling trucks, diesel powered auxiliary power units, and fuel operated heaters.
“Having the controlled environment of the test chamber allowed us to repeatedly test different scenarios under the same conditions,” said Jeremy Johnson, a TTI researcher who led the laboratory testing activities. “This allowed for a common basis to evaluate the results of individual tests.”
The findings from the project indicated that idle reduction technologies have the potential to reduce in-cab pollutant levels in a cost-effective manner. IRTs, normally used to reduce emissions and fuel consumption, can have the added co-benefit of creating a healthier working environment for truck drivers.