Lights. LED, rechargeable by USB. Daytime running, blinking, pulsing, “zoom” mode, steady, and group mode. Let’s focus on the last one for a moment. Bicycle light manufacturers are all about making lights brighter, and no one is making a case against this. But there’s a reason why one of these settings is specifically for use in groups.
Without getting too deep into the fundamental courtesy of not blinking a bright light in the face of the cyclists riding with you, I will simply say on the issue of manners that no one in the group is enjoying the blinking light in her face. Still, there’s something else at risk here that isn’t just a matter of conduct. Let’s get back to safety.
Riding at night is dangerous. Even with bright lights, there are dangers created by the glare. Everyone knows it’s blinding when a car comes toward you going the opposite direction on a dark road. The lights stand out of the blackness, and your eyes are helplessly attracted toward them, making it harder to refocus on the dimly lit road ahead of you.
When you blink your lights while on a group ride, you are negating the benefit of visibility to motorists by adding a visual obstacle to your fellow cyclists. Roads are hazardous enough. It should always be our highest priority not be part of adding to the risk. So, being polite aside, you want your eyes and your riding to be intentionally readied for the very real danger of night riding. Yes, it is fun, and I recommend we all do it more. But night or day, you’re always safer in groups, so long as you don’t hinder your friends by riding like you’re still by yourself.