system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: when repaving roads, why do they never repave the pavement on top or under a bridge?

Our roads are always under construction in Michigan. But when they repave them, both asphalt and concrete, above and sometimes below bridges are never done. Does this have to do with weight limits on the bridge?
gpt
Overhead clearance is a concern. If they simply pave over the old surface, the clearance between the new surface and the structure above it is reduced. 

I once shipped a boat (50’) to California. The driver took an approved route, but the road under an overpass in Chicago was recently paved and no one took the reduced clearance into consideration. About 10’ of roof was peeled off.