The California Air Resources Board (CARB) withdrew requests for approval of the Advanced Clean Fleets (ACF) rule, part of CARB emissions regulations. The proposal would have implemented stringent emissions requirements for heavy-duty diesel trucks and buses.

Though it approves similar legislation for cars, the EPA had yet to grant a waiver for CARB’s commercial vehicle-focused requests. President-elect Trump was expected to oppose these proposals when he takes office for his second term on Jan. 20.