Unless expressly provided otherwise, what color must a rear lighting device or reflector reflect?

The correct answer is that a rear lighting device or reflector must reflect red unless expressly provided otherwise. This requirement is rooted in safety standards designed to ensure that vehicles are easily visible from behind, enhancing safety on the road, especially during low-light conditions. Red is universally recognized for indicating the rear of a vehicle, which helps other drivers to distinguish the direction and presence of a vehicle from the back.

This is particularly important for preventing collisions and ensuring safe driving practices. The use of red for rear lights is consistent with traffic regulations, making it the standard color for taillights and reflectors on vehicles. Hence, adhering to this regulation not only fulfills legal requirements but also promotes safety on the road.