While I was in the hospital there was talk on TV about a new law on auto fuel economy. Nancy Pelosi said it was "the first improvement in auto efficiency in 32 years.' I wonder if other politicians are a ignorant as to what efficiency as she is. Efficiency is simply the percentage of input energy that becomes useful output. It is only slightly related to auto fuel mileage. On the other hand, mpg is strongly correlated to vehicle weight. Mileage improvements are usually achieved trhough vehicle weigh reduction, not through improved energy efficiency of the fuel consumed. Ms. Pelosi's law is more a social construct than anything else. She wants to force the peasants to start driving smaller cars. I don't have the data, but I suspect that there have actually been improvements in fuel efficincy over the past 32 years without any government action. One outcome of requiring only drastically smaller cars to be produced will be that the larger cars will remain on the road, maybe something like in Cuba. The new lighter cars, unless thay are very small, will cost much more to produce than current cars. This will make it attractive to repair the existing cars. I suspect that Ms. Pelosi, or her successor, will need a law to force the older cars off of the road. I have other contrarian views on this that I will write about later. I'm tired now. Open heart surgery does that to you.