The price is there to reduce congestion, not road damage per se. You want to charge by congestion causes, which is probably proportional to vehicle size, not we

The price is there to reduce congestion, not road damage per se. You want to charge by congestion causes, which is probably proportional to vehicle size, not weight. More broadly, trying to figure out a priori what is and is not useful for society is pointless. Moralizing economic decisions never works. Just charge people for the costs they incur and the optimally beneficial configuration will emerge on its own.