"A sample of 300 light-duty vehicles normally operated in the Denver metropolitan area was tested for emissions and fuel economy. The vehicles were from the 1978 through 1982 model years and included both passenger cars and light-duty trucks. One purpose of the program was to gather information for calculations and projections of ambient air quality. Another purpose was to assemble data on current model year vehicles for use in support of Inspection/Maintenance and other regulatory programs. The test sequence on all of the vehicles included the Federal Test Procedure, the Highway Fuel Economy test, and a series of short tests consisting of the Bagged Idle Test, the 50 mph Cruise Test, the Four Speed Idle Test, and the Loaded Two Mode Test. Some vehicles which exceeded Federal Emission standards were subjected to restorative maintenance and retested. [Evaporative emission tests using the Sealed Housing for Evaporative Determination (SHED) procedure were performed on 125 of the 1980-1982 model year vehicles. Other actions were taken in relation to each vehicle tested. These included an engine and emission control system maladjustment/disablement and status inspection, driveabilily evaluations, and owner interviews to obtain vehicle maintenance and usage data."--Abstract.