Safe Following Distances
The number of serious road accidents on our roads in the past few weeks brings to our attention again the need to stay alert and drive carefully on our roads. Most rear-end collisions are caused when drivers do not obey sufficient following distances. This is also known as tailgating.
Adequate following distances enable you to adjust in an emergency situation and bring your vehicle to a stop safely – time that could mean the difference between life and death.
Total stopping distance involves the following:
- Human perception time: The time required for a driver to recognise a potential hazard. This time is assumed to be approximately 0.75 seconds in normal situations.
- Human reaction time: Once the hazard has been perceived, the driver must respond by applying the brakes. The average reaction time is about 0.75 seconds
- Vehicle reaction time: This is the time it takes for the vehicle to react once the brakes have been applied by the driver. Vehicle reaction time is very quick, usually assumed to be about 0.05 seconds.
- Vehicle braking capability. This refers to the vehicle’s ability to come to a complete stop once the brakes have been applied
International studies have indicated that when a driver follows another vehicle at 100 kilometers per hour and the vehicle in front suddenly applies the brakes, the driver following will need at least one and a half seconds to react. If there is not enough distance between the vehicles – the driver following will not be able to stop in time.
The 3 second rule
Most International road safety campaigns refer to the 2 or 3 Second Rule as a guideline for safe following distances. A point on the road is noted, 2-3 seconds are counted, and if that point is still visible then there’s probably enough following distance. The South Africa Arrive Alive Foundation agrees with the National Safety Council’s recommendation of a 3-second rule, with increases of 1 second per factor of driving difficulty.
How to apply the 3 second rule:
- Watch the vehicle in front of you pass a landmark – such as a sign, tree, or power pole – at the side of the road.
- As it passes the landmark, start counting “one thousand and one, one thousand and two, one thousand and three”.
- If you pass the landmark before you finish saying all these words, you are following too closely. Slow down, pick another landmark and repeat the words, to make sure you have increased your following distance. This rule will ensure that you keep the correct following distance, no matter what speed you are traveling at.
Adjusting your following distance
The 2-3 Second Rule is only the advised measure when driving conditions are ideal. This should be seen as a bare minimum and should be adjusted to at least 5-6 Seconds in the following situations:
- In adverse weather conditions
- Driving on slippery roads
- Driving at night
- When following vehicles with different characteristics, i.e. motorcycles & trucks
- When towing a trailer or other object
Always drive defensively and focus on your safety and the safety of those around you. Don’t allow yourself to be tailgated. Rather change lanes or adjust your speed to encourage tailgaters to pass you. If someone cuts into your space, take a deep breath, simply back off a little and regain enough space. Remember, what counts is your safety!