I heard today that alcohol was not involved in the crash. Instead, the cause appears to have been impatience: a motorist who refused to believe that the TARC bus ahead of him or her had a good reason not to drive in the right lane and not to drive faster. A colleague pointed out that a driver following the bus at a safe distance could have seen the bicyclist in the right lane in time to avoid hitting her. The creepy raw video footage from the TV traffic helicopter showed the van stopped perhaps a hundred feet beyond where the smashed bicycle was propped against a tree. This gives me the impression that the driver went a significant distance after hitting the bicyclist before bothering to stop. This suggests that she or he was going faster than 35 mph (52 feet per second) or wasn't paying attention to driving, or both.
This crash and two of the four most recent fatal car-bike collisions in Louisville have involved motorists hitting appropriately visible bicyclists from behind. Though statistics show that most car-bike crashes involve motorists turning across the path of cyclists, the relatively infrequent car-hits-bike-from-behind crash is more deadly because the motor vehicle is more likely to be moving fast. This gives an explanation for the observed effectiveness of on-street bike lanes at reducing bicycle crash deaths.
I wish I could think about crash probabilities and driver education and street design in abstract terms, but I can't. There is innocent blood on the street. It makes me sick to see the inevitable come to pass. Impatient drivers taking unnecessary risks every day in often-futile efforts to save a few seconds. We now have a young bicyclist clinging to life because one of those drivers didn't get away with the impatient maneuver. The wrong person is suffering for it.