Mnemonic for Judging Vehicle Distance in Side Mirrors
2 Answers
Mnemonic for judging vehicle distance in side mirrors: The smaller the following vehicle appears, the safer it is; when the following vehicle occupies 1/3 of the mirror, the distance is about 10 meters; when it occupies 1/2, the distance is approximately 7 meters - suitable for turning; when the following vehicle fills the entire mirror, the distance is around 3 meters - not suitable for turning. Introduction to rearview mirrors: Structural principle of rearview mirrors: Rearview mirrors have a field of view issue, referring to the range that the mirror surface can reflect. The industry proposes three key elements of field of view: the distance between the driver's eyes and the mirror; the size of the mirror; and the radius of curvature of the mirror surface. These three elements are interrelated - when distance and size are equal, a smaller radius of curvature provides a larger reflected field of view. When the radius of curvature is equal, a larger mirror size provides a greater reflected field of view. Reflectivity index of rearview mirrors: Rearview mirrors also have a reflectivity index - higher reflectivity produces clearer reflected images. The reflectivity level depends on the reflective coating material on the mirror's inner surface.
Having driven for so many years, judging the distance of the car behind using the side mirrors is quite important. The rule of thumb is simple: if the car behind occupies more than half of the mirror, it means it's too close and there might be a risk of a rear-end collision; if it only takes up a small part, like a corner, it means the distance is safe. I personally make it a habit to glance before changing lanes and double-check with the blind-spot mirror. It's especially useful in heavy city traffic, helping me avoid a lot of trouble. I've also noticed that different cars have different visibility—SUVs, being higher, offer a better view, while sedans, being lower, provide a clearer view of other cars. I recommend practicing more while driving. Find a quiet place to park and have a friend move back and forth to test it out. Memorizing this rule can really boost your sense of security and make driving more reassuring.
