1. An apparatus for electromagnetically isolating an automobile having road wheels from an environment surrounding the automobile, comprising: a first chamber for the automobile; a second chamber disposed adjacent said first chamber; means for shielding said first and second chambers from passing of electromagnetic wave between said first and second chambers and environments around said first and second chambers; a wall disposed between said first and second chambers to cover said second chamber; road simulator units mounted within said second chamber; dynamometer means mounted within said second chamber in driving relation with said road simulator units; blowers mounted within said second chamber; a controller disposed outside said first and second chambers to prevent electromagnetic wave from entering said first and second chambers; conductors connecting said controller with said dynamometer means and said controller with said blowers; first filters disposed in said conductors to filter electromagnetic noise propagated from said controller to said dynamometer means; and second filters disposed in said conductors to filter electromagnetic noise propagated from said controller to said blowers.