cancel
Showing results for 
Search instead for 
Did you mean: 

Stopping distances

Moderator
Moderator
Posts: 16,524
Thanks: 1,780
Fixes: 123
Registered: 06-04-2007

Stopping distances

SWMBO is coming up to her practical driving test and is re-reading the Highway Code.
She was asking about stopping distances - I'm quite certain she won't be asked about them, though, as they would have been part of the theory test.
Back when I learnt to drive all stopping distances were in feet now they are, for some reason, in metres.
I think there was a formula such that:
Thinking distance was the current speed in feet +
Stopping distance was 3.5 times the speed in feet
i.e. At 70mph Thinking distance was 70ft and stopping distance was 245ft giving a combined overall stopping distance of 315 feet.
Is this correct?

Forum Moderator and Customer
Courage is resistance to fear, mastery of fear, not absence of fear - Mark Twain
He who feared he would not succeed sat still

2 REPLIES
Community Veteran
Posts: 1,894
Thanks: 3
Registered: 20-10-2012

Re: Stopping distances

Moderator
Moderator
Posts: 16,524
Thanks: 1,780
Fixes: 123
Registered: 06-04-2007

Re: Stopping distances

Spot on for 70mph but just realised my formal doesn't work for any other speeds.
Racking my brains (that's a task in itself) I now think I remember the formula as:
Quote
Thinking distance = Speed in ft plus
Stopping distance = (Speed multiplied by first digit of speed)/2
i.e. at 40mph Thinking distance = 40ft, Stopping distance = (40*4)/2=60ft: Total 120ft
at 60mph Thinking distance = 60ft, Stopping distance = (60*6)/2=180ft; Total = 240ft

Probably easier just to learn the distances  Cheesy

Forum Moderator and Customer
Courage is resistance to fear, mastery of fear, not absence of fear - Mark Twain
He who feared he would not succeed sat still