Push button dash

Starting in '66, various government fleets would not buy cars that didn't conform to certain specifications, some of which later became requirements of the Federal Motor Vehicle Safety Standards. Examples included reversing lights, sideview mirrors, and automatic shifts with no adjacent forward and reverse position. That prompted the automakers to standardize in those directions before they were actually required to by law. But pushbutton transmissions were never made illegal; Neoplan transit buses had 'em in the '80s and '90s, and some other makes of transit bus also have them (relevant because FMVSS 102, "Transmission shift position sequence, starter interlock, and transmission braking effect", applies to all vehicles equally).