That's near the inner city. Traffic is horrendous an hour or so earlier, but I'll bet it was backed up something fierce! And I'll bet there is a huge "rubbernecker" backup on the other side of I-65 too.
There is a mountain South of Birmingham called Shades Mountain. Every morning when I used to drive into Birmingham, traffic would stop about halfway up the mountain. Predictably, after a couple of seconds, traffic would flow again, pick up speed gradually... and there would be NO accident, stalled car... whatever.
It was simply one car tapping it's brakes, the car behind tapping it's brakes an infinitesimal bit more to keep from hitting the first car, the next car to the rear a little more, ad infinitum until the damn traffic on the interstate comes to a dadgum STOP a mile or so back. It is the craziest thing I have ever seen in traffic.