Fuel economy for any model type shall be measured in accordance with testing and calculation procedures established by the EPA Administrator by regulation. Procedures so established shall be the procedures utilized by the EPA Administrator for model year 1975 (weighted 55 percent urban cycle, and 45 percent highway cycle), or procedures which yield comparable results. Procedures under this subsection, to the extent practicable, shall require that fuel economy tests be conducted in conjunction with emissions tests conducted under section 206 of the Clean Air Act. The EPA Administrator shall report any measurements of fuel economy to the Secretary.