Safe driving distanceSafe driving as discussed in previous posts is important and keeping a safe driving distance is one of components of safe driving.

There is so called “three-second rule” which helps you to determine safe distance from the car ahead of you.

Of course, first, the distance changes at different speeds. To determine the safe driving distance, first select a fixed object on the road ahead such as a sign, tree or overpass. When the vehicle ahead of you passes the object, slowly count “one one thousand, two one thousand, three one thousand.” If you reach the object before completing the count, you’re following too closely. Make sure there are three seconds between you and the car ahead gives you time and distance to respond to problems in the lane ahead of you.

Second, the distance changes at different weather conditions and daylight. In night or when it is rainy or foggy, the three-second-rule should be doubled to the six-second-rule.

Three-Second Rule Safe Interval Should Be: 3 seconds 6 seconds
Speed Distance Traveled For These Conditions: Good Marginal
25 m.p.h. 37 ft. per second 111 ft. 222 ft.
35 m.p.h. 52 ft. per second 166 ft. 312 ft.
45 m.p.h. 66 ft. per second 198 ft. 396 ft.
55 m.p.h. 81 ft. per second 243ft. 486 ft.
65 m.p.h. 96 ft. per second 288 ft. 576 ft.
75 m.p.h. 111 ft. per second 333 ft. 666 ft.
Safe Following Distance in Feet
22 Nov 2010