What are the methods to judge the distance between vehicles?

[StMarley]

Methods to judge the distance between vehicles are: 1. When the upper edge of the rear bumper of the preceding vehicle is visible, the distance is 1 meter; 2. When the lower edge of the rear bumper of the preceding vehicle is visible, the distance is 2 meters; 3. When the rear tires' lower edge of the preceding vehicle is visible, the distance is 3 meters; 4. If the vehicle's reflection occupies the entire rearview mirror, the distance is 3 meters; if it occupies two-thirds of the mirror, the distance is 5 meters; if it occupies half of the mirror, the distance is 9 meters; if it occupies one-third of the mirror, the distance is 12 meters. Reasons for maintaining distance: 1. To avoid rear-end collisions caused by sudden braking of the preceding vehicle; 2. To reserve reaction time for handling emergencies.

[Cook]

There's actually a simple way to judge the distance to the car in front while driving: when you can fully see the rear wheels of the preceding car touching the ground, the distance is roughly about 3 meters, which is just right for city driving. For a regular sedan, if you can't see the lower edge of the rear bumper of the car in front, the distance is within 2 meters, which is too close. On the highway, you can use the 'two-second rule'—when the car in front passes a fixed object, you silently count '1001, 1002'; if you haven't reached that point by the time you finish counting, it's safe. I usually observe in the rearview mirror: when the headlights of the car behind appear in the lower third of my rearview mirror, it means the car is at least 10 meters away; if the car fills the entire rearview mirror, it's very close. Remember to increase the safe distance on rainy days.

[Tami]

Judging the distance of the following vehicle mainly relies on the interior rearview mirror. When the entire body of the following vehicle is visible in the mirror, the distance is usually over 20 meters, making it relatively safe to change lanes. If the following vehicle occupies about two-thirds of the mirror's area, the distance is approximately 15 meters, and lane changes should be approached with caution. When the front of the following vehicle fills the mirror, the distance is typically within 5 meters, and changing lanes is absolutely unsafe. Additionally, checking the side mirrors is also useful: when the following vehicle appears at the outer edge of the mirror, it's closest to you; when it's in the middle, the distance is moderate; and when it's toward the inner side, it's farthest. On highways, I prefer to signal early, observe the following vehicle's reaction, and then decide whether to change lanes, providing a double safety measure.

[CassandraFitz]

New drivers afraid of misjudging car distance? Practicing in parking lots is most practical. When parking facing another car's rear, stop when the rear wheels or bumper disappear from the driver's view - this leaves about 1 meter between your front bumper and their car. For reversing, check rearview mirrors - when the rear car's license plate is completely obscured by your rear windshield's lower edge, you're only 0.5 meters away and must stop. When teaching my cousin, I had him align wiper nodes with roadside markers to adjust side distance - when left node aligns with lane markings, the left wheels are 30cm from the line. These physical reference points are more reliable than guesswork.

[WillowDella]

At night, pay attention to changes in reflective points to judge the distance between vehicles. When you can clearly see the license plate text of the car in front, the distance is approximately within 10 meters; if you can only see the outline of the license plate without text details, the distance is about 15 meters or more. When checking the car behind, if the headlight beams appear as concentrated points in the rearview mirror, it indicates the distance is still far. However, if they turn into scattered large halos, be cautious of a potential rear-end collision. I always adjust the headlight height when driving long distances—this ensures good visibility for myself without causing glare in the rearview mirror that could affect judgment. Extra caution is needed in tunnels, as sudden entry into dark environments can easily lead to misjudgment of distance. Reducing speed in advance is the safest approach.

[McQuinn]

Don't completely rely on auxiliary devices even if your car is equipped with them. The guidelines in the reversing camera system are just references, with an actual distance error of about 20%. For models with radar, pay attention to the rhythm changes of the alarm sound—continuous beeping means only 30 cm remains. I've tested the distance measurement systems of different car brands and found that SUVs have larger blind spots due to their higher body height. It's advisable to develop the habit of turning your head to observe, especially when turning—directly look over your shoulder to check the blind spots on both sides of the vehicle, then use the devices to assist your judgment. Be extra cautious on sloped roads, as leaning forward or backward can significantly increase the radar's distance measurement deviation.