How to remember Stopping Distances
When preparing for your Theory Test, the stopping and braking distance questions can sometimes cause plenty of headaches when revising. But hopefully after you’ve finished reading this article you will be able to easily remember the correct stopping distances at various speeds.
The stopping distance is the distances covered by your car during sudden braking, and combines thinking and braking distance, from the moment you realise you need to brake to the moment when the car actually stops.
TIP: Here is a great way to remember the overall stopping distances. Starting from 20mph you simply multiply the speed by intervals of 0.5, beginning with 2, for example, 2, 2.5, 3, 3.5 etc as follows:
20mph x 2 = 40 feet
30 mph x 2.5 = 75 feet
40 mph x 3 = 120 feet
50 mph x 3.5 = 175 feet
60 mph x 4 = 240 feet
70 mph x 4.5 = 315 feet
The above calculations are a simple way to help you remember the correct stopping distances, but please be aware that these are approximate. The overall stopping distance is really the only safe separation gap, anything less than this can be considered a risk.
Braking and Stopping Distances
The diagram below shows the typical stopping distance. The distances shown are a general guide and will depend on your attention (thinking distance), the road surface, weather conditions and the condition of your vehicle.
In order not to pile into the vehicle in front, you should leave adequate space so you can pull up safely if the car ahead of you slows down or stops suddenly.
You must be able to judge the distance in front of you and you will need to practice estimating distance. Do this on foot. Select a spot in front of you; a road sign or a gatepost for example, guess how far away it is in metres, and count your steps until you reach it. A good stride will be roughly one metre. You can check your estimate against your actual measurement. It’s often further away than you think.
Typical stopping distances
Your overall stopping distance depends on the speed you are travelling at, the gradient or incline, the condition of the road, weather, brakes, tyres, and your ability to drive. If you are tired or sick, your reaction times will be slower. It takes well over half a second for most people to react. In that time, depending on your speed, your car will have travelled several more metres.
Multiple vehicle collisions, or pile-ups, are caused by drivers being too close to the vehicle in front, and not allowing for reaction time and stopping distance. A good rule would be to leave one metre for every mile per hour. For example, a speed of 30 mph would mean a gap of 30 metres. In wet weather, double this to 2metres.
More information on Separation distances.
Stopping Distances and ‘The Two Second Rule’
To check your distance from the car front is sufficient, apply this rule. Pick a point on the road ahead, a bridge or a signpost. When the car in front passes this point, it should take you at least 2 seconds (4 seconds in wet weather) to pass the same point. If it is less than two seconds, drop back and recheck. This is especially useful when driving at higher speeds, say, on the motorway or dual carriageways.
To minimize danger you should adopt defensive driving techniques of observation, anticipation, planning and restraint. Look well ahead of the traffic and see what might possibly cause them problems so you can be prepared.