Various aerodynamic improvement technologies have been evaluated under the US Environmental Protection Agency (US EPA) and California Air Resource Board (CARB) through different programs, such as US EPA Phase 1 and CARB's Tractor-Trailer Greenhouse Gas Rule (TTGHG). However, the majority of these technologies are developed considering mainly the heavy-duty class 8 long-haul tractor-trailers, leaving a gap regarding the potentials of using aerodynamic improvement technologies on medium-duty vocational vehicles.

The National Renewable Energy Laboratory (NREL) recently performed a series of highway tests on medium-duty vocational vehicles with and without aerodynamic improvement devices to assess their performance. The results indicate that adding an aerodynamic improvement device to certain types of vocational vehicles can result in a considerable fuel economy improvement. Based on these findings and CARB's recommendation, US EPA implemented a credit incentive for heavy-duty manufacturers in its Heavy-Duty Greenhouse Gas Phase 2 rule for the use of aerodynamic devices on some vocational box-type trucks. However, the realization of precise benefit under real-world driving conditions is strongly dependent on the vehicle activities and driving cycles. To fill this gap, this project aims to provide detailed information on the physical and operational characteristics of vocational vehicles in California, particularly on the Class 4-6 (Gross Vehicle Weight Rating 14,001 to 26,000 lbs) medium-duty vehicle population.

Accurate characterization of physical and operational characteristics of vehicles are critical to the development of appropriate air quality strategies. In pursuit of this goal, this project aims to obtain a clear picture of the vocation, types, and operational characteristics, such as operating speeds, daily activities, and driving distance of medium-duty vocational vehicles, particularly for class 4-6 vehicles (Gross Vehicle Weight Rating 14,001 to 26,000 lbs) operating in California.

Data on physical and operational characteristics of vocational class 4-6 vehicles will be obtained through an extensive online survey under this project. This survey will be conducted by the University of California, Irvine for the State of California on behalf of the California Air Resources Board (CARB), and in partnership with the National Renewable Energy Laboratory (NREL). Detailed data and information obtained through the survey will facilitate the understanding of the nature and operations of vocational vehicles that could benefit from the aerodynamic retrofit to reduce greenhouse gas (GHG) emissions, fuel consumption, and vehicle operating costs.

If you have question, please read FAQ