Given that he plowed into all five of them and they were in a dedicated bicycle lane, I'd say either full-blown texting (as in, eyes removed from the road) or downloading ring tones or very impaired and perhaps aggressively (especially if impaired) running them down. Leaving the scene and coming back when whatever he was on wore off, perhaps...

I noticed that while there were the normal number of 'we can kill cyclists so they need to go ride in a park somewhere' posts in the comments, the "approval" and "disapproval" ticks were much nicer to note.

When we had three accidents here this past two weeks (one fatal, two serious) I suggested that I wanted an Engine Killer Ray to render trucks and vans and SUVs impotent. (This was commented as "antagonistic rhetoric" by a couple of pontificators) I dunno, maybe the explosives instead of air bags would be better...