How to judge the distance between front and rear through the rearview mirror?
3 Answers
Use the following methods to judge the distance of the vehicle behind in the left lane through the rearview mirror: 1. If the body of the rear vehicle has entered the danger zone to the left of the dotted line in the rearview mirror, it indicates that the distance from the rear vehicle is very close, and turning at this time is not allowed. 2. If the left side of the rear vehicle's body is close to the boundary between the safety zone and the danger zone, you should be vigilant, but it is still safe to signal and turn at this time. 3. If the rear vehicle is in the safety zone, located in the center of the rearview mirror, it indicates that the distance from the rear vehicle is 15-20 meters, and you can proceed with the turning operation normally. 4. If the rear vehicle is in the safety zone, located to the right of the center of the rearview mirror, it indicates that the distance from the rear vehicle is relatively large, and you can proceed with the turning operation normally. Here’s how to judge the distance with the right rearview mirror: 1. If the rear vehicle occupies half of the rearview mirror area, and only half of its body is visible, the distance from the rear vehicle is very close. Your vehicle should maintain the current lane and not turn. 2. If the rear vehicle occupies half of the outer rearview mirror area, and the entire vehicle is visible, the distance from the rear vehicle is about 10 meters. You can signal and turn when the speed is slow. 3. If the rear vehicle occupies 1/3 of the outer rearview mirror area, and the entire vehicle is visible, the distance from the rear vehicle is about 15 meters, and you can proceed with the turning operation. 4. If the rear vehicle occupies 1/4 of the outer rearview mirror area, and the entire vehicle is visible, the distance from the rear vehicle is about 24 meters, and you can proceed with the turning operation.
I remember when I first started learning to drive, I was always worried that judging distances in the rearview mirror wasn't reliable. My instructor taught me to observe the relative size of the vehicle behind: in the mirror, if the other car looks like a tiny dot, it means it's far away, probably more than 30 meters; once it grows to almost fill the mirror, that indicates it's only about five or six meters away, and you need to be alert immediately. My practice method was to find a fixed reference point, like the white line on the ground when parking—when the rear of the car is parallel to it, a distance of about half a meter is just right. But as a beginner, I tended to focus only on the mirror and neglected to turn my head to scan the actual distance through the side window, nearly scraping the car several times. Later, I developed a habit: in city driving, I use the mirror for quick glances more often; on the highway, I rely more on a combination of senses, like listening for the engine sound getting louder, which signals the distance is closing. In short, this skill takes practice, and over time, it becomes second nature.
As an experienced instructor, I often tell my students that the key to judging rearview mirror distance lies in positioning perspective. Simply put, divide the rearview mirror into three parts: when the following vehicle is in the middle section, it's a safe distance; if it approaches the edge of the mirror, it's already very close. Here's how to do it: first adjust the mirror angle to ensure the view covers the blind spot behind the car, then observe the vehicle's movement trend. For example, on city roads, if the other vehicle maintains a stable size, the distance is basically unchanged; if it suddenly becomes larger or smaller, it means it's accelerating or decelerating toward you. I recommend combining roadside references when reversing, like tree trunks or road markings, to help calibrate the actual distance. For safety, develop the habit of anticipating early: check the mirror for two seconds before changing lanes to see if the following vehicle is catching up quickly. Remember, distance judgment isn't just visual - you must also consider vehicle speed and road conditions for a comprehensive assessment.
