What are the methods for judging the distance of a car seen in the rearview mirror?
3 Answers
You can judge the distance of a car seen in the rearview mirror by the size of the rear vehicle in the mirror. The following is an introduction to the rearview mirror: 1. Introduction: The rearview mirror is a tool that allows the driver to directly obtain external information about the rear, side, and lower parts of the car while sitting in the driver's seat. For the convenience of the driver's operation, to prevent traffic safety accidents, and to ensure personal safety, all countries have stipulated that rearview mirrors must be installed on cars, and all rearview mirrors must be adjustable in direction. 2. Installation position: (1) Interior rearview mirror: The interior rearview mirror is designed to confirm the rear view without significantly changing the forward line of sight while driving. (2) Exterior rearview mirror: Passenger cars generally install exterior rearview mirrors on the doors. In Japan, some vehicles also have them installed on the fenders.
Having driven for over a decade, I've picked up some practical tips for judging distance using rearview mirrors. When checking the side mirror, if the car behind occupies the entire mirror surface, it's too close—just a couple of meters at most. If the rear car fills only half the mirror, the distance is roughly 10 meters. And if it's only a third of the mirror's size, that indicates a safer distance of over 20 meters. The interior rearview mirror is also helpful: if you can see the entire front of the car through the rear windshield, the distance is acceptable; seeing only the license plate means it's too close. Always check multiple times before changing lanes, as the car behind might accelerate. Pay extra attention in bad weather—distance perception worsens significantly in fog. For beginners, sticking a small convex mirror on the car body can aid visibility.
When I first started learning to drive, I was always nervous about lane changes. Now, I'm quite comfortable judging distances using the rearview mirror. The key is observing the proportion of the following car in the mirror: if an entire car fills the mirror, it's dangerous with a distance definitely under 5 meters; when the following car appears very small, occupying only one-fifth of the mirror, it's safest, indicating at least 30 meters away. At night, pay attention to the size of the other car's headlights: bright, glaring lights mean they're close, while softer lights indicate greater distance. On highways, extra caution is needed—higher speeds require longer safe distances. I recommend checking the rearview mirror for two seconds longer than usual before changing lanes. During rainy days when roads are slippery, I double my usual distance judgment for peace of mind.
