Have you ever ran into a crane hook from a shop crane, hanging just above your eyes so you dont notice because your eyes navigate down in front of you, so you smack your forehead into the crane hook whilst navigating the cluttered shop floor in front of you ? (I always rise them above head, or lower them to below shoulder height when i walk in the shop and see a crane hook at forehead height)
Same with trucking, you need your eyes on the road so its easy to miss something in the sky. For that reason, many low overpasses in the neighbouring city have a beam suspended on chains before the overpass. Hitting that at 40mph makes enough noise to warn drivers ahead so they can take the on-ramp before the overpass.
People who hit bridges arent as dump as you think they are: they just pay attention to traffic.