SAN FRANCISCO -- Engine manufacturers must install computer systems on big-rig trucks operating in California to diagnose and warn drivers of emission problems, according to an order issued by state air quality regulators on Thursday.
The order by the California Air Resources Board is the first such regulation in the United States for heavy-duty trucks.
The U.S. Environmental Protection Agency is expected to approve a similar rule to develop and install on-board diagnostic systems for diesel and gasoline engines, according to the California agency.
An estimated 1 million to 1.5 million trucks weighing more than 14,000 pounds travel on California highways, each emitting more than 5 pounds a day of nitrogen oxide, the principal ingredient of smog, and soot, according to the Air Resources Board.
The diagnostic system, which will be phased in for big-rig engines from 2010 through 2016, is linked to tougher California pollution rules for trucks that will take effect from 2007 to 2010.
Computer hardware and software will monitor fuel, catalysts, exhaust recirculation, soot filters, cooling and other systems and alert the driver to problems as they occur via warning lights on the truck's instrument panel and pinpoint areas that need repairs.
The Air Resources Board estimates the diagnostic system will cost $132 per truck.
The Engine Manufacturers Association said makers of heavy-duty truck and bus engines have been working with the California regulators to develop the new regulations.
The Engine Manufacturers Association, which represents companies such as General Motors, Cummins Inc. and International Truck and Engine Corp., said in testimony to the agency that "further work is essential and changes must be made" to assure that a diagnostic standard "is technologically feasible and cost-effective."