Drunk drivers kill bicyclists sometimes, but overall it's quite rare. Plan for safety, but, as Ira B just stated, sometimes it's just going to happen. And not just to bicyclists, but to people doing anything - I don't think anything is risk-free.

A lot of cities seem to plan their bicycle lanes and routes on busy streets. I tend to avoid them and ride through neighborhoods, even if the route is not as direct. But no matter what I do, close calls eventually happen.