A highway bridge at 7 ft., 7 in. -- what could go wrong?

There's a parkway near here that has a 10' 9" railroad bridge over it. Can't be raised because of it being a RR line. Can't lower the road because it's next to a lake. There's at least 1/2 dozen signs AND it's closed to commercial traffic but trucks still go down it and hit the bridge. The worst accident was a Megabus that killed 4 passengers. They've done everything including painting the bottom of the bridge blaze orange, nothing works.