> If those costs were paid by the drivers and owners of heavy vehicles, those people would be more likely to purchase smaller and lighter vehicles.

Outside of fuel consumption, which indeed is directly paid for by the person who owns the car, It's all paid for by taxpayers, and like any public service some people don't use it as much as others (or at all). Everyone in NYC pays for the subway yet some people own a car and drive it exclusivity.

> I imagine most people would be pleased to drive on smooth roads with less air pollution.

This largely doesn't matter to most people since cars have very good air filters[0,1]. I also question how much a regular consumer truck actually contributes to road wear compared to the millions of 18 wheelers that weigh over 50,000 pounds.

0: https://www.tesmanian.com/blogs/tesmanian-blog/tesla-hospita...

1: https://www.kbb.com/car-news/will-my-cars-filter-system-help...