The 4th power claim is alarming, yes. But are we focused too much on road wear and not enough on the money spent to increase the capacity of roads? My gut says

The 4th power claim is alarming, yes. But are we focused too much on road wear and not enough on the money spent to increase the capacity of roads? My gut says that widening a road is at least an order of magnitude more expensive than maintaining one, so whatever we can do to reduce the number of cars is more worthy of focus than just getting all the trucks off the road.