You are travelling in very heavy rain. Your overall stopping distance is likely to be _________.

Related Information

What is the stopping distance?
The total distance you travel before applying the brakes, plus the distance you travel while the brakes slow you down, is the stopping distance.
In which:

The thinking distance is the distance traveled between the time the need to brake is realized and the time it takes to activate the brakes, usually approximately one foot for every mph you travel. So, if you're driving at 30 mph, your thinking distance is about 30 feet.
Braking distance is the distance your car travels after you apply the brakes until it comes to a complete stop. The more your speed, the more momentum you have, and the greater your braking distance.

It's important to note that the predicted stopping distance formula assumes the driver is not distracted or drunk, is driving a well-maintained car, and is driving in normal, dry road conditions.

What are average stopping distances?
At 30 km/h, the dry distance is 10.8 meters while the wet distance is 14.9 meters.
At 50 km/h, the dry distance is 24.0 meters while the wet distance is 35.2 meters.
At 60 km/h, the dry distance is 32.4 meters while the wet distance is 48.5 meters.
At 80 km/h, the dry distance is 52.7 meters while the wet distance is 81.4 meters.
At 100 km/h, the dry distance is 77.7 meters while the wet distance is 122.6 meters.
At 120 km/h, the dry distance is 107.5 meters while the wet distance is 172.2 meters.
One thing to keep in mind from these data is that your stopping distance does not simply double when your speed doubles; it increases far more. For example, at 60 km/h, your stopping distance is three times greater than at 30 km/h.

You’re driving in very heavy rain. How will your overall stopping distance be affected?
When driving in wet or rainy circumstances, the Highway Code dictates that your total stopping distance in heavy rain or even wet weather will be at least double that on a dry surface.
There are two basic causes behind this. The first is that a wet road surface is more slippery, resulting in less tyre traction to the road and increased braking distance. Furthermore, unfavorable weather conditions such as heavy rain can substantially impair visibility on roads, increasing your reaction time before braking.

What are tips for driving in the rain?
Wet surfaces can almost double your stopping distance, so drive slowly and carefully.
Keep your air conditioner running to keep your windows from steaming up.
Use dipped headlights to make yourself visible to other vehicles, but avoid using rear fog lights, which might dazzle other cars.
Do not spray other drivers, and if you are sprayed by another fast-moving car, remain calm and increase the speed of your wipers to clear your windscreen.