When must low beam headlights be used on the Autobahn?

Answer: C — When visibility is substantially reduced

The use of low beam headlights on the Autobahn is mandated primarily for safety during conditions of reduced visibility. This includes situations such as heavy rain, fog, snowfall, or other environmental factors that can limit a driver’s ability to see or be seen. When visibility is substantially reduced, low beam headlights help illuminate the road effectively without causing glare for oncoming traffic, which is crucial on high-speed roadways like the Autobahn. While it is true that headlights should be used at night, there are also times during the day and in certain weather conditions when visibility may not be optimal, making it necessary to switch to low beams for safety reasons. This practice helps ensure compliance with traffic regulations and promotes a safer driving environment for everyone on the road.