One of the basic notions that every student who leaves a driving school has etched in their mind is the importance of a safe distance when driving. The teachers emphasize the importance of maintaining adequate space between our vehicle and the one in front of us on the road to guarantee not only our own safety, but also that of other road users.
The safety distance is like a protective cushion that gives us the time and reaction capacity necessary to avoid collisions, brake safely in emergency situations and, ultimately, contribute to the prevention of accidents. To calculate the correct distance, speed, braking conditions and grip must be taken into account.
The safety distance will be greater when we travel on a highway at 120 km/h than when we do so in an urban center where the speed is limited to 30 km/h. The General Directorate of Traffic (DGT) advises that the distance be at least two seconds, because this is the time it takes to perform an emergency braking.
To calculate this period of time, it is recommended that we pronounce the figures ‘1,101, 1,102…’ with respect to a fixed point on the road to know exactly the distance at which we must travel in relation to the vehicle in front of us.
Now, there is another method that the Civil Guard proposes to calculate the safety distance in meters. This is the Square Rule. It consists of taking the speed at which we are traveling, for example 90 km/h, and removing the last figure (zero), leaving 9, and multiplying it by itself: 9 x 9 = 81. Thus, at 90 km/h h a minimum distance of 81 meters must be left.
Other examples proposed by Benemérita in the message published on her official X profile (formerly Twitter) follow the same pattern. That is, we must always ignore the last digit of the speed at which we are traveling and then multiply the resulting figure by itself.
With this rule, at 100 km/h we would have to leave 100 meters of distance (10 x 10 = 100) and at 120 km/h, 144 meters (12 x 12 = 144).
The Civil Guard accompanies the post with a fun illustration, as it sometimes does, to try to get the message to capture the attention of users. In this link you can see some of the messages published by the armed force in X where the sense of humor is evident.
In certain driving situations, the safety distance must be even greater, indicates the DGT in its publications. It stands out that in some sections where a multiple collision can be disastrous, in a tunnel for example, it is advisable to extend this distance to at least 100 meters or a 4-second interval.
Likewise, Traffic recommends multiplying the safety distance by two when the ground is wet or raining. Thus, at a speed of 90 km/h, if the dry safety distance is 81 meters, with wet ground it is double that, that is, 162 meters. On the highway, driving in the rain at 120 km/h, the safety distance that we must leave with respect to the vehicle in front of us is 288 meters, instead of the 144 meters that we would leave with dry ground.
