Getting better MPG’s while sticking

In July, President of the USA announced a plan to ensure that all auto makers would be required to take steps to increase the fuel efficiency of passenger vehicles to 54.5 MPG by 2025. This is expected to save the typical family a bundle at the fuel pump, reduce oil consumption by 12 billion barrels over the course of the program, and reduce carbon dioxide pollutant levels by six billion metric tons.
Sounds like a win-win – doesn’t it? Not so fast. Like all government programs, there’s a catch, and it catches you, the consumer. If car makers were capable of producing a car with this kind of fuel mileage, why isn’t it already on the market?
Conspiracy theorists would say it’s because they’re in the pocket of the big oil companies, but there are a few saner reasons why we’re driving around in petrol-hungry cars: common sense says that either the auto makers CAN’T do it at this time or it’s just too expensive.