[ams6110]

Trucks are taxed more already. The problem is legislatures using those tax revenues for other pork and then claiming to not have enough money for roads.

[jessaustin]

Semi trucks reduce the quality of the roads much more than lighter vehicles do. The slightly greater tax they pay doesn't begin to make up for it.

http://fhwicsint01.fhwa.dot.gov/policy/hcas/addendum.cfm