[benVFR]

The thing is if the speed limit gets dropped again new cars will be adapted in short order.

1) Gear ratios will be optimized for 55mph, mpg will go way up
2) Fuel mapping may change, mpg may go up a little
3) If people slow down average hp/weight in the cars will likely drop (people switching to four-bangers instead of V8 SUVs, etc..) and there will be an even bigger gain in mpg.
4) If average speeds really do drop safety structures may get toned down to the point vehicle weights start to come down, another huge mpg difference. This could further occur as if the average vehicle weight drops then the safety structure needs drop even further.

My car has total suck ass gearing for highway traveling, but it's pretty aerodynamic and it doesn't really drop much as I speed up. It's rated 31mpg on the highway and I've easily gotten that averaging 75-80mph.. Slowing down might only affect it 2-3mpg. But then again if I had an SUV... If they changed 6th gear to something sane it'd probably pick up 5mpg.

MPG effects on bikes are totally nuts. 55mpg smooth riding on back roads I get nearly 50mpg on my VFR, 75mph highway driving I'm dropping into the high 30mpg range.

If Hilary and McCain think it's a good idea to drop the gas tax for the summer we do not want to see what the federal budget & deficits will look like if either of them ends up in office. (But then again last time I checked Obama doesn't exactly mention saving money often either)

55 feels really slow to me in the car but I think if the car(s) were optimized to loaf along at 55mph I'd be a lot more patient.