Emission Performance of Properly Maintained Vehicles

The U.S. Environmental Protection Agency routinely tests properly maintained and used light-duty cars and trucks to determine their compliance with exhaust and evaporative emission standards. Manufacturers of nonconforming cars and trucks may be required to recall and repair the vehicles. This paper summarizes the results of EPA in-use testing for 1977 through 1982 model year cars and discusses trends in the performance of each model year’s fleet. Data are presented from cars of selected major manufacturers which show that current gaseous exhaust emission standards are being achieved by most manufacturers.