My wife worries quite a bit. There have been a couple of cases in the last 5 or 6 years of cyclists killed on roads that I sometimes use for my commute, so that hasn't helped. I was also involved in two auto-involved crashes in the first year that I biked to work.

The biggest compromise we've negotiated is that I don't bike in the rain after dark. Other than that, I let her know when I'm going to be getting home later than normal. I also periodically remind her of the amount of accidental death and dismemberment insurance I get through work. (Should I be worried that she's pacified by that information?)

Generally when there's a high profile bike crash in our area I try to find out all I can about it to understand how it might have been avoided. I do this for my own benefit, but often my wife and I talk about it.

Case like you mention with someone who "swerves into the traffic lane" for reasons that the investigators seem not to be able to identify are frighteningly common. I'm pretty sure that the elusive reason is usually that the person got caught in the air stream of a high speed vehicle and lost control. This is one of the reasons I avoid roads with high speed limits and/or frequent big truck use.

Obviously the risks are out there and some dangers can't be avoided or prepared for, but the more you learn the safer it seems.