When adjusting the left exterior rearview mirror, position the vehicle's body so that it occupies one-quarter of the mirror surface, and align the horizon with the center of the mirror. When adjusting the right exterior rearview mirror, similarly position the vehicle's body to occupy one-quarter of the mirror surface, but place the horizon at the two-thirds mark of the mirror's height. It is recommended to perform this adjustment while standing outside the vehicle at the driver's eye level to ensure accuracy.
While driving, use your peripheral vision to glance at the rearview mirrors every 5 to 8 seconds to stay aware of surrounding traffic conditions. Even with proper adjustment, blind spots remain; therefore, you should also check the interior rearview mirror and utilize safety aids such as blind-spot monitoring systems.
According to national standards, exterior rearview mirrors must allow the driver to clearly see the area behind the vehicle-covering a width of 2.5 meters at the rear of the vehicle-with a field of view spanning at least 45° horizontally and 10° vertically.