If cars can be fuel-efficient, why can't education be time-efficient?

That's the premise that Republican U.S. Senator Lamar Alexander is promoting.

Alexander served as U.S. education secretary in the administration of the first President George Bush and also as president of the University of Tennessee.

Speaking at the Reuters Washington Summit, Alexander suggested that more colleges take a look at allowing at least some students to obtain an undergraduate degree in three years rather than the normal four. "It's one way to attract students," he said.

How does he expect colleges to respond? "Skeptically," Alexander said. "Colleges don't change easily."

He said that the idea has been tried and worked on a limited basis -- and that the marketplace will likely determine how widespread a three-year degree becomes.

The United States has the best universities in the world, and they have been key to developing competitive advantages that help Americans produce 25 percent of all the world's wealth, he said.