A minor accident could have prevented the major one.

After hearing from so many witnesses about how aggressively Diane was driving and also watching the part of the gas station video that wasn't shown on the documentary where Diane pulled into traffic without even pausing, it's amazing how many accidents she actually avoided. If she had a fender bender with even one of the people earlier in the day, then the police would have discovered that she had been drinking, and the head-on collision never would have happened.