For those of you who watch any TV it is hard not to see the ad from a well known auto insurer running about safe following distances, with the actor standing at the side of the road saying --
However, according to the Wisconsin Motorist's Handbook (the book Wisconsinites study prior to taking the written exam for our driver's licenses) a safe following distance is at least four (4) seconds, not two (2) seconds.
What does this mean to a driver? It means you should wait until the vehicle in front of you passes a fixed object like a sign, light pole, bridge, etc... Once this happens, you then count 1 thousand 1, 1 thousand 2, I thousand 3, 1 thousand 4. If you are four (4) seconds behind the vehicle in front you should be passing the fixed object when you are finishing your 1 thousand 4 count. However, if you pass the fixed object before you reach finish your 1 thousand 4 count this means you are following too close.
The Wisconsin Motorists Handbook
It is important to note that the Wisconsin Motorist's Handbook goes on to state that the minimum four (4) second rule applies under ideal driving conditions like dry roads in the middle of summer Ideal driving conditions are considered dry roads with clear and sunny weather (summer weather). The snow, ice and slush we experience on Wisconsin roads are not considered ideal driving conditions because they all affect your ability to stop. Under these driving conditions you have to leave even more space between your car and the vehicle in front of you. Also a hard rain can cause hydroplaning, which also makes it hard to control and stop your vehicle. Thus, under these adverse weather conditions everybody has to increase their following distances to avoid a crash.
You should know that if you are following a vehicle too closely and rear-end the vehicle in front of you, ninety-nine percent (99%) of the time the crash will be your fault
Additional resources provided by the author
You can click on the link below to view the current edition (May 2010) of the Wisconsin Department of Transportation's Motorists' Handbook.