That is a good point, but I was thinking of it in terms of 2 roads are going to cross and rather than make an intersection you have the choice of a bridge or a

That is a good point, but I was thinking of it in terms of 2 roads are going to cross and rather than make an intersection you have the choice of a bridge or a tunnel. On that road, the same trucks/bicycles/etc will use it regardless of your choice, so the tunnel can't be any less "height aware" than the bridge.