The only benefit that comes from 55 mph speed limits is the truckloads of revenue local municipalities would collect. All in the name of saving the kids.
Of course, what gets me is how the automobile is seen as the root of carbon evils even though it doesn't even account for 25-percent of greenhouse emissions.
Whatever benefit there might be from this reduction will simply be offset by the increase in the construction of coal plants elsewhere.
Why not target all sources instead of just going after the low hanging fruit?
http://www.nytimes.com/2008/04/23/wo...yt&oref=slogin
http://en.wikipedia.org/wiki/Image:G..._by_Sector.png