How to Judge the Distance Between Cars When Driving?

[AaronLee]

Methods to judge the distance between vehicles are as follows: 1. When the lower edge of the rear wheel of the car in front aligns with the lower edge of the windshield, the distance is 3-5 meters. 2. When the lower edge of the front car's bumper aligns with the lower edge of the windshield, the distance is about 2 meters. 3. When the upper edge of the front car's bumper aligns with the lower edge of the windshield, the distance is 0.5-1 meters. 4. When the image of the rear car occupies the entire rearview mirror, the distance is about 3 meters; when the image occupies two-thirds of the rearview mirror, the distance is about 5 meters; when the image occupies half of the rearview mirror, the distance is about 9 meters; when the image occupies one-third of the rearview mirror, the distance is about 12 meters.

[KiaraAnn]

The method I use most often while driving is the rearview mirror judgment technique. By observing the appearance of the car behind me in the mirror: if it fills the entire mirror surface, it's probably about 5 meters away—too close, so I need to be careful; if it only occupies half the mirror, the distance is roughly 10 meters; if just a small front end of the car is visible in the mirror, then it's at least 15 meters away, which is a safer distance. When following another car, I silently count to three—after the car in front passes a utility pole, I count 'one-thousand-one, one-thousand-two, one-thousand-three' before passing the same spot. This method works especially well on clear days. In rainy or foggy conditions, I add another half-second to the count, leaving a longer braking interval for safety. When changing lanes, besides checking the mirrors, I also turn my head to look, as the area around the C-pillar is where electric scooters are most likely to hide.

[DiStephanie]

As a beginner, I was particularly afraid of side scrapes, but later I summarized a few reference points. For the left wheel position, look at the hood ridge line; for the right side, check the wiper node. When passing another car, if the curb reaches the lower edge of the door handle, there's about 30 cm of clearance. In narrow roads, if you can touch the wall by rolling down the window and reaching out, there's still half a meter of space. Always maintain a distance of at least 5 seconds from large trucks—when they brake hard, it feels like a black hole sucking you in from behind. When parking, if the lower edge of the front car's bumper disappears from view, you're about three meters away, and that's when the parking sensors start beeping the most urgently. On rainy days when the windows fog up, these reference points can shift, so you need to allow for more safety margin.

[McDerek]

On the highway, the most feared situations are fog patches and sudden deceleration. I’m accustomed to using the two taillights of the car ahead as a gauge—when I can clearly distinguish the two separate light clusters, the distance is about 50 meters. If the lights blur into one, it’s time to slow down immediately. In tunnels, I rely on reflective markers on the walls, with a diamond-shaped sign every 40 meters. When following a car, if the lower edge of my windshield aligns with the tires of the car ahead, the distance is at most 15 meters, which is dangerously close. Before overtaking a large truck, I first check if its front wheels show any signs of turning. When driving alongside, I can feel the airflow tugging at the steering wheel. In the city, when stopped at a red light, seeing the entire rear bumper of the car ahead indicates a distance of about two meters, which is ideal—not too close to invite cut-ins nor too far to be inefficient.