Semis cause 1,400x more wear than cars [1].
Maybe. Reduced transportation costs to businesses permit lower cost goods to end consumers. Your car transporting you to work isn't your only reliance on the road grid.
Buying less stuff > spending tens of extra hours per week getting from place to place.
I'm not sure the potato subsidy is worth distorting the transport economics.
Then again, if everyone in my apartment complex splits a water bill, there's not much incentive for me to use less water.
If it's truly the heavy vehicles ruining the road, and so we somehow charge the much more, then perhaps measures will be taken to address that cost...
"Talk about a ‘superload’! Check out what just crawled along Washington highways"
http://www.seattletimes.com/seattle-news/talk-about-a-superl...
If the road maintenance cost of transporting the potatoes is priced into the potatoes, then the potato company might opt to transport the potatoes in a different (cheaper) way.
But if the road maintenance costs appear free or near-free to the potato company, they have no incentive to care about it. Also it makes drivers who don't eat potatoes subsidize the potato consumers.
That's actually not true. Capitalism always works, no matter the problem. However, free markets don't account for externalities, and in some cases supply/demand constraints create unacceptable non-economic problems. Thus, to avoid the effects of non-economical problems then it's preferable to create economic incentives that reflect the non-economic constraints.
If the potato trucks had to pay for the full cost of roads, then they would be incentived to drive that cost down.
Aligning incentives is important.
More realistically, potato prices would go up to reflect operational costs.
Net result would be better prices for local farms, less road maintenance needed, no impact to the end consumer overall (less taxes to support less roads).
