The California Air Resources Board Friday adopted two regulations aimed at cleaning up harmful emissions from the estimated 1 million heavy-duty diesel trucks that operate in California.

Beginning January 1, 2011, the Statewide Truck and Bus rule will require truck owners to install diesel exhaust filters on their rigs, with nearly all vehicles upgraded by 2014. Owners must also replace engines older than the 2010 model year according to a staggered implementation schedule that extends from 2012 to 2022.

Also adopted, the Heavy Duty Vehicle Greenhouse Gas Emission Reduction measure requires long-haul truckers to install EPA Smartway-certified fuel-efficient tires and aerodynamic devices on trailers tp lower greenhouse gas emissions and improve fuel economy.

CARB officials say that heavy-duty big rigs are the largest remaining source of unregulated diesel emissions, responsible for 32 percent of the smog-forming emissions and nearly 40 percent of the cancer-causing emissions from diesel mobile sources.

The greenhouse gas reduction measure applies to more than 500,000 trailers, while the diesel regulation applies to about 400,000 heavy duty vehicles that are registered in the state, and about 500,000 out-of-state vehicles that do business in California.

However, because many heavy duty vehicles are replaced or retired due to normal business practices on a faster schedule than what the new regulation will require, the number of vehicles expected to be retrofit by 2014 under the rule is about 230,000, while up to 350,000 vehicles would be replaced earlier than normal over the next 15 years.

To help truck owners upgrade their vehicles, the state is offering more than $1 billion dollars in funding opportunities. To provide flexibility, the diesel regulation is structured so that owners can choose from among three compliance options to meet regulation requirements.

CARB staff held dozens of workshops and met with hundreds of business owners and other stakeholders over the last 20 months. Without the diesel regulation, California will not be able to meet U.S. EPA-mandated air quality standards and deadlines, and could subsequently lose billions of dollars in federal highway funding.

For more information on the Statewide Bus and Truck Regulation:

For more information on the Heavy Duty Vehicle Greenhouse Gas Reduction Measure: