Spot Highway Inspections of Diesel Trucks to Resume

After a lengthy suspension, the California Air Resources Board voted Thursday to reinstitute spot highway inspections of diesel-powered, heavy-duty trucks and buses.

The law applies to vehicles weighing over 7,000 pounds.

Unlike gasoline-fueled passenger cars and light trucks that face routine smog checks, diesel trucks and buses have not had to undergo regular inspections since 1993, although they produce a disproportionate amount of smog.

Heavy-duty trucks and buses make up only about 2% of the vehicles on California roads. But they are responsible for 30% of the nitrogen oxides and 60% to 65% of fine particle, sooty pollution that is a primary component of smog, according to the air board.

The board reinstated annual fleet inspections of diesel trucks and buses that rarely travel on freeways but use city streets.

Fleet owners will be required to inspect their vehicles and submit records to the Air Resources Board.

The board said the inspection law will take effect in about 90 days but has not set a date.

The highway checks will be conducted by eight to 10 teams of inspectors stationed at border crossings and weigh stations around the state, according to the board.

Trucks emitting excessively smoky exhaust will have to undergo a roadside testing procedure in which electronic monitors will measure the opacity of engine exhaust as acceleration is increased.

Vehicles that fail will be required to undergo necessary repairs and, in most cases, owners will face $300 fines. Subsequent violations will lead to fines up to $1,800.

School buses will be exempt from fines if repairs are made within 45 days.

The inspection law went into effect in 1991 but was suspended two years later after owners complained that the exhaust monitoring was often inaccurate.

The air board asked the Society of Automotive Engineers to develop calibration standards to ensure uniform readings from all instruments.

“We wanted to avoid situations where operators were saying their monitors were giving one set of results and ours were giving another,” said Jerry Martin, a spokesman for the air board.