What lights are required in the back of a bus or trailer that is wider than 80 inches?

In a situation where a bus or trailer is wider than 80 inches, the requirement for safety lights includes the installation of two red tail-lamps. These tail-lamps are essential for visibility and to alert other drivers to the presence and dimensions of the vehicle, especially in low-light conditions. They help to indicate the vehicle's position on the road, which is critical for safe driving, particularly for larger vehicles that may be more challenging to see.

The existence of two red tail-lamps ensures that there is redundancy in the system—if one lamp fails, the other will continue to function, maintaining visibility. This safety requirement is regulated to prevent accidents and improve road safety, which is why it is mandated for wider vehicles.