I won't tell you about what happened to me on a motorcycle once! I survived it intact tho. Nothing has happened to me on a bicycle yet (jinx).

I saw an article, I think it was in NYT, that said about 600 people got killed riding bicycles last year. That doesn't seem a terribly high number if accurate. How many people choked to death on food? More injuries on bikes, then fatalities, of course.

Riding a bicycle is a lot less dangerous in many respects, then a motorcycle. Even if you have some sort of collision with a car while on a bicycle, you won't have been traveling as fast as you might have been on a motorcycle.

Hope that helps the wife relax a little. Get good lights, helmet, and brightly colored clothes, learn defensive riding techniques, and the odds are in your favor.