Damage Prevention. So that you don't have a three mile-an-hour bump kill your engine/headlights/whathaveyouThe requirements promulgated under MVICS were consolidated with the requirements of Federal Motor Vehicle Safety Standard Number 215 (FMVSS 215, "Exterior Protection of Vehicles") and promulgated in March 1976. This new bumper standard (...) applicable to 1979-model year passenger cars, were called the "Phase I" standard. At the same time, a zero-damage requirement, "Phase II", was enacted for bumper systems on 1980 and newer cars. (...) 5 miles per hour (8 km/h) front and rear barrier and pendulum crash tests were required, and no damage was allowed to the bumper beyond a 3?8 in (10 mm) dent and 3?4 in (19 mm) displacement from the bumper's original position.
All-seasons instead of proper winter/summer tires, stone-age halogen headlights instead of active matrix LEDs (they are illegal, somehow) and AFAIK some states still don't make car owners have their vehicles inspected annually.European safety standards aren't as high as the US of A's.