Flashing your headlights is a well-established means of communicating any number of things to other drivers on the road. It could be a reminder for the other driver to turn on their lights (or turn off their brights). Maybe it’s a call to your traveling partners in another car to pull off at the next exit. It’s also a way for some people to alert other drivers about a police speed trap up ahead. Some towns have outlawed that practice, but a federal judge says that’s going too far. [More]