Originally Posted by Johnny Footstool
The government already has a ton of influence. It regulates emissions, safety standards, etc. Requiring automakers to produce a certain percentage of cars that pass MPG standards wouldn't be so terrible.
Government regulations required passive restraints, leading to automatic seatbelts and then airbags.
Government regulations required a percentage of all cars sold to be hybrids or use alternative fuels by 1995, IIRC.
That second one isn't doing so well.