The grants would be used to offset the incremental cost of purchasing cleaner engines in the course of business. In addition, diesel vehicles contribute about 65 percent of the small particulate matter known as PM10 that comes from on-road vehicles. PM10 contributes to respiratory disease by lodging deep in the lungs and is suspected of causing cancer and birth defects. The Details ARB inspectors will measure the opacity of smoke coming from a vehicle's exhaust system. Engines from 1991 and newer fail with an opacity reading of 40 percent or greater and receive a citation.
Fine money goes to fund research into cleaner diesel engines and cleaner diesel fuels.
School buses are exempt from fines if violations are corrected within 45 days. Research has shown that excessive smoke from diesel vehicles generally results from improper maintenance of the vehicle's fuel system or because of tampering with the engine. Getting trucks into compliance resulted in extended engine life and improved fuel mileage. It is estimated that approximately 17 million gallons of diesel fuel are wasted each year in California by trucks with fuel systems that are not maintained to manufacturer specifications.