From the Mailbag:
Are there any laws regarding riding a bike at night? i.e.- are lights or reflectors mandatory? Is there any data that supports the idea accidents are more likely to occur at night verses other times of day (early morning or peak traffic times)?
Good question! In the previous post, I talked about the requirements for lights and reflectors. In this post, I’ll briefly show some statistics about when bicycle crashes are occurring.
From 1999 to 2008, the Mn/DOT crash database includes a total of 9,382 crashes involving a bicycle. There were no doubt many more crashes that occurred during these 10 years that weren’t reported. The following is a histogram showing the number of crashes that occurred during each one-hour time period throughout the day:
It should not be surprising that the data shows more crashes occurring during the day than during the nighttime, because there are obviously many more cyclists on the road during these hours. This doesn’t tell us anything about the probability of being involved in a crash, however. To determine that, we would also need to know the number of bikes on the road during each hour throughout the day (and possibly how far cyclists are traveling during these times as well). Unfortunately, this is data we simply don’t have.
If anyone knows of any academic studies regarding the probability of crashes throughout the day, please let us know about it by leaving a comment.