Howard Payne: Jack, nothing tricky now. You know I'm on top of you! DO NOT attempt to grow a brain!
If you look at the missing part of the bridge, and look at the shadow underneath, the shadow is of a full bridge.
The famous "Dukes of Hazzard" sequence was the filmmakers' wry commentary on the uncompleted state of Interstate 105, which had become a running joke among LA motorists. It was finally (and quite uncoincidentally) completed in late 1993 shortly before the film's release, years behind schedule.