Weave, these insane laws are not passed because of a concern about pollution. They are just like the laws here in Michigan & in Ohio, where cars can go 70 mph and trucks are restricted to 55 mph. These laws are passed because lawmakers see them as a way to get themselves re-elected. Lawmakers (most) and the media have an image of truckers, which is not very favorable. The general public see trucks as being driven by tired, foul mouthed, slobs that are operating poorly maintained and overweight vehicles at excessive speeds, that are dangerous to 4 wheelers and in their way on the highway. By passing such absurd laws, the legislaters can go to the public and say "see, we are trying to protect you and the environment." You would have a hard time convincing me that legislators do anything that is not related to gathering more votes, i.e. more power.
Drive Safe