What must the reflectors be capable of doing when mounted on a vehicle?

The reflectors mounted on a vehicle must be easily visible from great distances to ensure that other drivers can see the vehicle in low-light conditions. This visibility is crucial for safety on the road, as reflectors play a key role in preventing accidents, particularly during nighttime or in poor weather conditions. Reflectors are designed to bounce light back to its source, making the vehicle stand out to oncoming drivers or those approaching from behind. The ability to be seen from a distance helps other road users gauge the presence and position of the vehicle in time to take necessary actions to avoid collisions.

While other options suggest interesting features that reflectors might have, such as indicating the size of the vehicle or providing color-coded warnings, the primary function of reflectors is visibility. This focus on visibility is essential for vehicle safety regulations and is a fundamental requirement for all vehicles operating on public roads.