Be careful- this isn't true everywhere. In the municpality I lived in until May, a light had to be clearly visible from a distance of a certain distance (500 feet?), and if memory serves, someone posted on here this spring about getting a DUI in Seattle (or maybe Portland) after getting stopped for insufficient lighting. That said, there are very few places where law enforcement would have an issue with insufficient lighting. My old town's police department has essentially declared war on cyclists "for our own good" (they threatened to impound one of my bikes because it was locked to a streetlight for five minutes and wasn't registered in their ridiculous database, which they pretended addressed our substantial theft issue. The officer actually waited next to it for me to come out of the store). Insufficient lighting is one of their major targets (and probably the only one that makes any sense).