Motor Vehicle Regulatory Improvement Act of 1979

Motor Vehicle Regulatory Improvement Act of 1979 - Amends the Motor Vehicle Information and Cost Savings Act to: (1) establish average fuel economy standards for model years 1981, 1982, 1983, and 1984; (2) eliminate the authority of the Secretary of Transportation to prescribe or modify such standards; (3) eliminate the authority of the Administrator of the Environmental Protection Administration to prescribe rules for the calculation of average fuel economy; and (4) permit credits earned for exceeding the required fuel economy levels for any given model year to be used to offset any penalties such manufacturer may have incurred for the three consecutive model years prior to such year.

Amends the National Traffic and Motor Vehicle Safety Act of 1966 to prohibit the Secretary of Transportation from requiring that any passenger car be equipped with any automatic device or mechanism which enables such car to meet any frontal crash protection requirements prescribed by the Secretary.

Amends the Clean Air Act to modify emission standards for carbon monoxide, hydrocarbons and oxides of nitrogen from light-duty vehicles and engines manufactured after model year 1979. Establishes a national primary ambient air quality standard with respect to ozone. Permits the Administrator to submit to Congress for approval by June 30, 1985 a proposed national primary ambient air quality standard to take effect on September 30, 1987.