Barack Obama is criticizing U.S. auto makers for poor fuel economy, and claiming that Japan and China average much higher (about 45mpg rather than the US 29mpg). While this speech makes good politics, and Senator Obama will get praise for giving it in Detroit, it ignores a few unpleasant facts.
Yes, fuel economy is higher in some other countries. That's because the cars are all much smaller than in the U.S. When we look at cars sold in the U.S. by domestic and foreign auto makers, all manufacturers average about 27-33mpg according to the NHTSA web site (http://www.nhtsa.dot.gov/cars/rules/cafe/FuelEconUpdates/2003/index.htm
). The overall average is 29mpg, with the domestic makers around the average. The fact is that there isn't very much variation in the fleet economy (not counting companies like Ferrari at 14mpg).
Japanese cars may average 45mpg in Japan, but the Japanese don't sell those cars in the U.S. Instead, they sell the large cars that US consumers will buy. I was talking to somebody a couple days ago who was driving his "economy" car, a Lexus (Japanese make) which got 30mpg highway (less city) as opposed to his Lexus SUV that averages about 15mpg.
There is nothing stopping Japanese makers from selling small high mileage cars in the U.S. But a simple look at the Honda Civic shows the trend. From 1973 until today, the Civic grew from 140 inches long to 177 inches long. Curb weight went from 1500lbs to about 2900lbs. Fuel economy has dropped, the original getting 40mpg highway, the current one 30mpg. I can't find 1973 overall fuel economy for the Civic, but today's model is in the mid 20's.
Certainly the hybrid Civic, like the Prius, provides much higher mileage. And Detroit has perhaps made a mistake in emphasizing ethanol fuel instead of hybrids, but we're still left with the question of fuel economy in the United Stetes. Small cars don't sell.