You should be constantly on the defensive to prevent a rear-end collision with other vehicles. This applies not only to the vehicle you are following, but also to the vehicles following you.
The collision from behind may not always be avoidable, but the professional driver can reduce the probability. The first step in prevention is assuring that your own stops are smooth and gradual. To do this, practise these simple but effective driving habits:
- Look well ahead at the traffic to pick out the clues that indicate speed changes and stops developing in the traffic pattern.
- Look ahead for traffic control devices to anticipate light changes before reaching the intersection. Traffic lights that have been green for some time before you reach the intersection are probably stale and could change at any time. Streets with synchronized lights permit you to adjust your speed to the traffic lights.
- Maintain an adequate following distance from the vehicles ahead so that a smooth, gradual stop may be completed, even if the vehicle ahead has made a panic stop.
The law prohibits the practice of driving in a caravan. Drivers of semi-trailer units, trucks and buses will sometimes drive in caravans so the first truck breaks the wind resistance for those following closely behind. This leaves insufficient stopping distance and prevents faster traffic from passing one truck at a time.
Using time to estimate your following distance
If you drive a taxi, ambulance, police vehicle or van, you should maintain a three-second interval between your vehicle and the vehicle ahead. To estimate the distance between you and the vehicle in front, follow these steps:
- Pick something that is on or near the road and is not moving (for example, a sign, pavement patch, shadow or overpass).
- When the rear bumper of the vehicle you are following is even with the object you have chosen, start counting - "Thou - sand and one, Thou - sand and two, Thou - sand and three," etc.
- When your front bumper is beside the chosen object, stop counting. This will give you the number of seconds between you and the vehicle you are following.
- If you are closer than three seconds, drop back and check again until you have achieved a minimum of a three-second following distance. Any following distance longer than that is safe.
If you drive a power unit, semi-trailer, bus, truck or truck and trailer, round out the length of the vehicle to the nearest metre and divide by three to determine your count.
Example: If your truck and trailer is 14.6 m, round to 15 m, then divide by three.
15/3 = 5-second count
When road conditions change because of rain, snow or ice, lengthen the count to suit the changing conditions.
Space must be allowed for other vehicles to pull in between you and the vehicle ahead.
A short observation of the driving technique of the driver ahead will tip off the professional driver as to what might be expected. If the vehicle ahead is a tailgater, you can expect to have frequent "panic stops." The driver ahead who maintains a safe following distance usually has a longer, lighter brake application for stops, giving you adequate notice by their brake lights that they are slowing down.