Know your stopping distances

Know your stopping distances

The seasons change, the weather deteriorates and we head inevitably towards Winter, it is time once again to think about road safety and in particular, tyres. Everyone knows this, or should, but it never hurts to reiterate that, along with braking performance, the tyres on our cars perform the most vital part of stopping a car safely. It’s that critical.

There are a number of factors that affect braking and stopping distance. The Highway Code offers specific online advice for driving in adverse conditions. It’s the law. Here then are some timely reminders:

Stopping Distance

The law requires that tyres should have a minimum tread depth of 1.6mm. That’s fine as it stands but a vehicle running on such tyres will require up to sixty percent more road to come to a halt. This is because when tyres wear down there is a deterioration in their performance during cornering and when braking in a straight line. This is especially true in the wet. As tread depth decreases, a tyre is unable to deal with the same volume of water on the road. That in turn affect traction (grip) and braking performance.

The stopping distance is the amount of clear road needed to bring a car to rest from any given speed. Not allowing for this distance is why there are so many tail-end shunts. For example, a car travelling at just thirty miles per hour will need 23 metres (75 feet) to stop and that is assuming tyres in good condition on a good road surface. As speed increases so the distance required increases exponentially. There are however other factors at play relevant to stopping distance:

Thinking Distance

Different people react differently to different situations but even folk with lightning fast reactions cannot brake the instant they see a hazard. It takes that extra second to hit the pedal and this in turn is dependent upon concentration. Distracted driving really is a thing these days.

The average thinking time is thus around a second and, at 50mph, the car will travel around fifteen metres. It’s quite a sobering thought. It should also be taken into account how a person is feeling: The common cold can affect how an individual reacts, as can medication and, it goes without saying, alcohol.

Weather & Road Conditions

Bad weather means longer stopping distances. Rain adds a sheen of water on surfaces, ice and snow more so; all of which the tyres have to deal with. Assume therefore the worse the conditions the longer the stopping distance. Even after a long dry spell, a little rain can make a road surface greasy.

Add to this the condition of the roads themselves. Many of our highways and byways are in less than perfect condition. This is another distance increasing factor to take into account.

Braking Distance

This relates to how far the vehicle travels once full emergency braking pressure is applied and again assumes that the brakes are tip top. If in any doubt about braking performance, if the pedal feels ‘soft’, say, then get them checked out by your local car servicing garage.

The Highway Code states that once braking is applied it takes 14 metres for a car to come to rest. Add to this the human condition, the thinking distance and the road conditions and that seemingly long stopping distance makes more sense.

How To Be Sure

The general working condition of a vehicle; tyres and brakes as mentioned, but also suspension and steering, all count towards a safer experience. Get your local MOT and service garage to check out the car if in doubt. That is after all what the MOT test is for.

For added security think about your personal driving standard. Do you allow enough time? Are you too close to the motor in front? What are the conditions like? These are all questions we, as responsible drivers, should ask ourselves every trip. The alternative is to find out about stopping distances the hard way.

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