What is the method for judging the distance to the following vehicle using the left and right rearview mirrors?
3 Answers
The method for judging the distance to the following vehicle using the left and right rearview mirrors is: 1. Using the center of the rearview mirror as a reference line, when the vehicle body is on the outer side of the reference line and the following vehicle cannot be fully seen, the distance is 5 meters; 2. When the following vehicle can be completely seen in the rearview mirror and the vehicle body is aligned with the reference line, the distance is 10 meters; 3. When the following vehicle is aligned with the central axis of the rearview mirror and there is a width of one vehicle between the following vehicle and the outer edge of the rearview mirror, the distance is 15 meters; 4. When the following vehicle is aligned with the central axis of the rearview mirror and there is a width of two vehicles between the following vehicle and the outer edge of the rearview mirror, the distance is 20 meters.
From my experience of long-distance driving, the most reliable method to judge the distance of the car behind is to observe the position changes of the car in the left and right rearview mirrors. The left mirror is flat, showing the actual size: if the car behind occupies the entire mirror and the body is clearly visible, it is estimated to be only 3-5 meters away, which is too close; if only the front part of the windshield is visible, it is about 10 meters away, which is safe; when the car body is not visible and only a little shadow is seen, it is very far away. The right mirror is convex, making objects appear smaller and easy to misjudge: when the car behind occupies the center of the mirror, it is quite close, within 5 meters, so be careful; when it occupies a quarter of the edge, it may be more than 10 meters away. In actual driving, I adjust my judgment based on the speed, such as when driving at high speed, the car behind quickly filling the mirror indicates rapid approach. Additionally, remember to adjust the mirror angle to reduce blind spots, such as turning your head to look out the window for confirmation instead of relying solely on the rearview mirror. With daily practice, it becomes natural and helps prevent rear-end collisions.
I found the techniques I learned as a novice driver incredibly practical and easy to apply. Checking the left rearview mirror: if the rear car's wheels are visible, it means they're very close; if the entire car body is in the middle, it's at a moderate distance; if it's near the top of the mirror, it's far enough for a lane change. The right rearview mirror has a curvature that makes cars appear smaller, so when a car appears in the center, be extra cautious as it might actually be very close, requiring you to slow down. While driving, I habitually use the three-second rule to judge distance changes by counting time: pick a fixed point like a road sign, start counting after the car in front passes it, and if the following car reaches the point within three seconds, the distance is tight. For added safety, make more use of peripheral vision or a quick glance to scan blind spots outside the windows—don't rely solely on mirrors. Practicing these a few times makes them easy to remember and boosts confidence, helping to avoid misjudgments.
