Trucks drivers must carefully navigate around low clearances at bridge, tunnels and overpasses. In fact, trucks in New York State are not allowed on any Parkway for this very reason. Unfortunately, many truck drivers come from out-of-state and miss the low clearance signs ending up in truck accidents like the one depicted to the left.
In Australia, they are experimenting with a cool technology that warns truck drivers of an impending strike by instantaneously producing a sheet of water and projecting a “STOP” sign on it via lasers. These pop-down stop signs have successfully prevented semi trucks from striking various structures including the Sydney Harbour Tunnel. Below shows the dramatic and effective result.