The **rearview mirrors** are essential for improving the driver's visibility to the sides and behind the vehicle. For a side rearview mirror to be properly adjusted, it must allow the driver to see the **maximum of the road laterally**. This means that the driver should adjust the mirror so that they can observe as much of the road as possible on their side, which is crucial for detecting approaching vehicles, cyclists, or pedestrians.

- In cars, vans, and trucks, it is common to have a mirror on the left side and another on the right side, although the latter is not mandatory. These mirrors help cover blind spots and provide a wider view of the road.
- On motorcycles, depending on the speed at which they travel, it is mandatory to have one or two mirrors to ensure good lateral visibility.

Adjusting the mirrors to see the road instead of the side of the vehicle maximizes driving safety, as it allows the driver to be more aware of their surroundings and react appropriately to any situation on the road.