More of a crash avoidance system than a conventional safety system, many new vehicles are equipped with daytime running lights. Activated by the ignition switch, these typically are high-beam headlights at reduced intensity or low-beam headlights at full or reduced power. The lights, which increase contrast between vehicles and their background to make cars more visible to oncoming drivers, are an inexpensive way to reduce multiple-vehicle daytime crashes. In Canada and other countries where they're required, daytime running lights have reduced daylight, car-to-car crashes. Such lights aren't currently required on new cars in the United States, but they're permitted.