It's not that everyone does it all the time. It only has to happen, say 1% of the time. Combine that with the number of cyclists on the road, and the thousands

It's not that everyone does it all the time. It only has to happen, say 1% of the time. Combine that with the number of cyclists on the road, and the thousands upon thousands of car doors opened each day, and odds are it will happen. As the article states, it happens on average once per day in Chicago. It's not a lot, but it is a problem.