Calculating and being aware of the safe stopping distance is key for safe and secure driving. Here are a few tips and techniques to make sure you've stopped before it's too late.

Your thinking distance always remains the same as your mph. At 20mph your thinking and braking distances remain the same. Therefore at 20mph your stopping distance is 40 feet.

Travelling at 30, 40, 50, 60 or 70mph multiply your mph by half of the first digit of your travelling speed gives you your braking distance. Therefore at:

• 30mph you multiply by 1.5
• 40mph you multiply by 2
• 50mph you multiply by 2.5
• 60mph you multiply by 3
• 70mph you multiply by 3.5

Therefore at 30mph, your braking distance equals 30 x 1.5 = 45ft plus your thinking distance of 30ft gives you your overall stopping distance of 75 feet. So for the braking distance is 40mph x 2 = 80ft plus your thinking distance of 40ft equals an overall stopping distance of 120ft .

Important

Stopping distances are doubled for wet roads.
Multiply stopping distances by ten for icy roads.
Complicated! Look at the highway code rule 105.