Trucks operating in California will face twice-yearly “smog checks” under new regulations approved by the California Air Resources Board (CARB).

The process applies to equipment with a gross vehicle weight rating of more than 14,000 lb., and will also include independent owner-operators who were exempted from today’s periodic smoke inspections.

Telematics users will be able to submit the onboard diagnostics information using existing systems, CARB said. Older heavy-duty vehicles without on-board diagnostic systems would conduct opacity tests with an added visual testing component.

The Heavy-Duty Inspection and Maintenance Program will also roll out a network of roadside emission monitors to focus on high-emitting trucks, beginning in the San Joaquin Valley and South Coast. Plans are in place to expand that network over time.

Random tests will be introduced at border crossings, California Highway Patrol weigh stations, fleet facilities, and random roadside locations, CARB added.

About 1 million trucks and buses will be affected overall, and by 2037 the program is expected to reduce NOx and particulate matter by 82 tons per day. Over time, trucks with on-board diagnostic capabilities will see checks four times a year.

“This common-sense measure will provide the pollution reductions we urgently need to achieve federal air quality standards and deliver cleaner air to impacted communities near ports, freeways, and warehouses,” said CARB chairwoman Liane Randolph.

The US$4 billion program is projected to yield US$75 billion in health-related benefits from 2023-2050.

U.S. Senator Connie Leyva said the program will lead to the largest reduction in NOx emissions since truck and bus regulations were adopted in 2008.

“It is long overdue that big diesel trucks undergo smog check testing so that we can continue to clean our air and improve public health across California,” Leyva said.