In addition to hazard warning lights, what must farm tractors and self-propelled units manufactured after January 1st, 1972 have?

Farm tractors and self-propelled units manufactured after January 1, 1972 must have two head lamps in addition to hazard warning lights to ensure the safety of the vehicle while it is in operation. This requirement is intended to enhance visibility for both the operator of the tractor and other drivers on the road, particularly in low-light conditions or during inclement weather.

The presence of two head lamps allows for better illumination of the road ahead, making it easier to navigate and reducing the risk of accidents. As farm tractors operate often on public roads, especially in rural areas where lighting may be inadequate, the requirement for two head lamps is a key component of ensuring that these vehicles can be seen by others, thus promoting overall safety on the roads.

Other options, while they may seem relevant or useful for visibility, do not encompass the critical safety measures mandated for farm tractors in conjunction with their auxiliary warning systems. Hence, the specification of two head lamps stands as an important regulatory requirement.