Alex Tabarrok: >I doubt that there is much of an environmental effect - the main environmental effect is due to congestion not speed limits.<
Texas, at this moment, is wrestling with what to do about speed limits in order to satisfy the EPA. For now, the speed limit in the Houston-Galveston area is 55. (This has not gone down well.) The Texas Natural Resource Conservation Commission (yes, they made it singular -- which may be why the Legislature decided to change its name altogether) finally got around to looking at data and learned that heavy vehicles at top speeds produced far more NOx etc. than passenger cars. So now they're trying to figure out a way to persuade the EPA, the Texas Dep't of Transportation, and not least truck drivers that there should be two speed limits in non-attainment areas such as Houston-Galveston -- 70 for cars, 55 for the big rigs. Michael
