2008 California Statewide Truck and Bus Rule

The California Statewide Truck and Bus Rule was initially adopted in December 2008 by the California Air Resources Board (CARB) and requires all heavy-duty diesel trucks and buses that operate in California to retrofit or replace engines in order to reduce diesel emissions.^[1] All privately and federally owned diesel-fueled trucks and buses, and privately and publicly owned school buses with a gross vehicle weight rating (GVWR) greater than 14,000 pounds, are covered by the regulation.^[1]

Implementation was originally scheduled for January 1, 2011 but recent amendments were considered in December 2010. The rule now requires the installation of particulate matter filters beginning January 1, 2012 and replacement of older engines beginning January 1, 2015. Nearly all applicable vehicles are required to have 2010 model year or the equivalent to 2010 engines by January 1, 2023.^[2]