Totally agreed that construction costs should be distributed in a manner proportional to usage. I'm curious though; is road damage based on total vehicle weigh

Totally agreed that construction costs should be distributed in a manner proportional to usage. I'm curious though; is road damage based on total vehicle weight, or just the weight on each tire? If the latter, I think the formula should reflect that in order to incentivize vehicles to distribute weight across more tires in order to minimize road damage where that makes sense. I'm also curious about how much wear is caused by vehicles vs other factors, like the weather. I'd guess that probably depends a lot on the local climate in each state. I should also point out that maintenance costs aren't the only cost associated with road usage; even light cars take up space on the road, creating traffic and thus reducing the utility for other drivers. Any charges should thus include the cost of additional lanes needed to accommodate those vehicles regardless of their weight. In an ideal world I'd probably base the cost on miles driven, plus an additional charge based on an estimate of additional maintenance costs incurred depending on mileage, vehicle weight, number of tires, and the local climate. But then you also have to take into account the bureaucratic cost of enforcement, and how complicated you can make things before those costs exceed the benefits of accurate distribution of costs to consumers. Definitely a complex issue.