All of the developed industrial nations of the world have government mandated fuel economy standards. These standards force automakers to produce vehicles with a certain minimum efficiency. In the United States, the relevant legislation is called CAFE or Corporate Average Fuel Economy. Detroit has long grumbled about CAFE and there is a body lobbyists who have tried (and are trying) to weaken the required efficiency. Looking around at the other nations, it is quickly seen that the US has very weak fuel economy standards. The report Comparison of Passenger Vehicle Fuel Economy and GHG Emission Standards Around the World in fact shows that the US has the weakest requirements of all. The chart above, taken from the report, shows that European, Japanese and Chinese vehicles are required to be considerably more fuel efficient than US cars.
This has permitted Detroit to fill the garages of the nation with gas guzzlers. This was not a large problem in the past era of cheap gasoline. But it has not prepared us at all for the dawning future of permanently high gasoline prices.