I do not live around there, so I do not know, but is it big rigs that strike the bridge? I would think that most of the rig drivers use GPS/maps for trucks and will rarely be around this location (of course, there is always exceptional individual drivers, but I suspect that after a strike or two they find themselves out of a job). I would have guessed that the problem is really the typical garden variety UHaul renter or small company truck that uses GPS/maps for cars and is not paying attention to signs for height restrictions.
Why have not passive warning devices gained much traction around low clearance bridges? In Europe, crossings where the rail has overhead wire have these beams installed ahead of the crossing with weights on them set at a lower height than the catenary. A tall truck that would strike the catenary would first bang on those weights waking up any distracted driver not paying attention to the height restrictions. That would seem like a very appropriate system for low bridges, especially ones that have had frequent strikes.