California Air Board Releases Draft Rules to Reduce Diesel Exhaust

November 12, 2008 | The California Air Resources Board (CARB) has unveiled for public comment its latest draft version of two landmark regulations that, if adopted at the Board’s December hearing, will clean up emissions from the estimated one million heavy-duty diesel trucks that operate in California beginning in 2010.

The first proposed regulation will require truck owners to install diesel exhaust filters on their rigs starting in 2010, with nearly all vehicles upgraded by 2014. Owners must also turn over engines older than the 2010 equivalent according to a staggered implementation schedule between 2012 and 2022. Further, long haul truckers must install fuel efficient tires and aerodynamic devices on their trailers that lower greenhouse gas emissions and improve fuel economy.

The state is offering truck owners more than a billion dollars in funding opportunities to help with the cost of the proposed diesel rule. Funding options include Carl Moyer grants, which are designated for early or surplus compliance with diesel regulations; Proposition 1B funds, for air quality improvements related to goods movement; and Assembly Bill 118, which establishes a low-cost truck loan program to help pay for early compliance with the truck rule.

Diesel emissions are toxic, associated with cancer, and can also exacerbate cardiovascular and respiratory ailments. According to CARB, the truck regulation is expected to save 9,400 lives between 2010 and 2025, and greatly reduce health care costs. These benefits have a value of $48 to $69 billion. CARB says the cost of installing the trailer greenhouse-gas-reducing technologies will be quickly paid back through lower fuel use.

ARB staff held dozens of workshops and met with hundreds of business owners and other stakeholders over the last 18 months. Flexible funding options exist and the ARB is working to create more so that this regulation can be fully implemented at the lowest cost.

According to CARB, without this 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.

To provide flexibility, the diesel regulation is structured so that owners can choose from among three compliance options to meet regulation requirements. There are exceptions to the regulation, including low-use vehicles, emergency and military tactical vehicles, and personal use motor homes. School buses would be subject only to requirements for reducing diesel particulate matter and not for engine replacement.

To better assist truckers, ARB is evaluating ways to integrate these programs so that truckers can get a grant and a loan at the same time, minimizing paperwork and significantly reducing the monthly payments for a new truck loan. 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 (other diesel emitters include trains, off-road vehicles and marine engines). The rules are expected to impact more than 400,000 trucks registered in the state, as well as about 500,000 out-of-state vehicles that do business in California, and over a half million trailers.

To reduce diesel emissions and improve air quality and public health, the ARB adopted a Diesel Risk Reduction Plan in 2000 and has already passed regulations addressing urban buses, garbage trucks, school bus and truck idling, stationary engines, transport refrigeration units, cargo handling equipment at ports and rail yards, off-road vehicles, port trucks and other sources.

The Air Resources Board is a department of the California Environmental Protection Agency. More information is available at