Does taxing by the mile include a higher tax-per-mile for heavier vehicles?In other words, does the weight of the vehicle "weight" the tax?

No to both questions. In Oregon, heavy trucks are taxed by weight and miles, and that wouldn’t change. In the Road User Fee Pilot Project, passenger cars paid a fee based only on the miles traveled in Oregon, regardless of weight. Here’s why: Oregon Highway Cost Allocation Studies have determined the difference in pavement damage imposed by a 6,000-pound large sport utility vehicle versus a 3,500-pound compact car is inconsequential as compared to the difference in the damage imposed by either of these vehicles versus a fully loaded, 80,000-pound truck. Although all passenger vehicles do the same about of damage to the roads, they do varying amounts of damage to the environment. Finding the balance between "user fees" for roads and environmental impact will be an issue for the legislature if the road user fee is considered. The rate could be weighted for variables such as emissions, fuel-efficiency, or other factors to encourage Oregonians to invest in purchasing environmentally- ...  more