Even with gas prices cresting above $4 a gallon, large SUVs, pickup trucks and even Toyota Priuses barrel down freeways here in suburban Detroit at more than 75 miles per hour -- well beyond the 55 mph that was the national speed limit during the '70s and '80s.

If the U.S. Energy Department's calculations are right, all these lead foots could save the equivalent of 29 cents to 94 cents a gallon if they slowed down just to 60 mph -- and reduce the fuel they burn by about 7% to 23%. But most of my neighbors and I still choose to hit the gas rather than add 10 or 15 minutes to our commute times.

While energy policy debates are abstract, the speed you drive on the freeway is real. Most Americans are in favor of burning less "foreign oil." Not as many want to slow down to achieve that goal. This is cognitive dissonance on a mass scale. It would be good to talk this out, and Americans will likely get that chance. The idea of adopting a nationwide, slower speed limit is coming around again.

The federally mandated 55 mile per hour speed limit put into force in 1974 by the Nixon administration did curb fuel consumption. But it was one of the most unpopular moves the government made during the energy crisis of that decade.

One of the few Americans who might have a good word to say about the old "double nickel" is Sammy Hagar, the rocker who scored a hit with a song titled, "I Can't Drive 55."