How dangerous is biking?

I just found out a good friend's sister was killed training for a Triathelon. She was biking in the morning and hit by an SUV. One of our Oregon swimmers was similarly killed earlier this year. Every time I read about a Triathlete it seems somewhere in the story they had to spend a year recovering from when they were hit by a car. Is this as common as it seems? I don't know what we can do,but it seems we should do something.