The California Air Resources Board (CARB) Tractor-Trailer Greenhouse Gas (GHG) Regulation requires 53-foot-or-longer box-type trailers and the tractors pulling them to be equipped with aerodynamic technologies and low rolling resistance tires when operating on California highways.

The intention of this regulation is to reduce overall emissions, including GHGs, by improving fuel mileage (less fuel burned means less emissions generated). The regulation applies to any tractor-trailer combination that includes a box-type trailer (dry van or van-type refrigerated trailer) that is 53 feet or more in length. Specific regulatory requirements include the following:

• Trailers covered by this regulation must be equipped with:
  • Aerodynamic equipment that improves the fuel mileage, and
  • Low rolling resistance tires.
• Sleeper-berth-equipped tractors that pull covered trailers on a California highway must be equipped with:
  • Full aerodynamics meeting the U.S. Environmental Protection Agency (or U.S. EPA) SmartWay standards, and
  • Low rolling resistance tires.
• Day-cab tractors that pull covered trailers on a California highway must be equipped with low rolling resistance tires.

There are exemptions available for short-haul, local-haul, and storage trailers. To qualify as short-haul or local-haul trailer, the trailer must operate entirely within 100 miles of its normal base of operations. To use any of the exemptions, the carrier must register the trailer in the Tractor-Trailer GHG Portal (Trailer Reporting) system.