Indeed. Trucks cause several orders of magnitude more road wear than cars, because road wear scales like weight per wheel to the fourth power (this might not always be the perfect model http://www.nvfnorden.org/lisalib/getfile.aspx?itemid=261 but even so the general idea holds), and trucks weigh a whole lot. If trucks had to pay their fair share of road maintenance, shipping by truck would probably be noticeably more expensive.