Added: 23 August 2017

Brake, the road safety charity, is calling on the Government to increase stopping distances in its next update to the Highway Code because drivers' thinking time has been under-estimated.

 

Brake asked the Transport Research Laboratory to provide evidence on the time taken by car drivers to perceive, recognise and react to emergency situations.  TRL referred to academic literature and concluded that the average thinking time is 1.5 seconds - more than double the 0.67 seconds set out in the Highway Code.

 

This means that average total stopping distance -including thinking and braking distance - is an extra 2.75 car lengths (11 metres, on the basis that the average cars is four metres long) at 30mph and an extra 3.75 car lengths (15 metres) at 40mph compared with the distances used in the Code.  This difference rises to an additional 6.25 car lengths (25 metres) at 70mph.

 


Overall average stopping distances

Speed

20mph

30 mph

40 mph

50 mph

60 mph

70 mph

Brake/TRL study

19m

34m

51m

71m

95m

121m

Highway Code

12m

23m

36m

53m

73m

96m

Difference

7m

11m

15m

18m

22m

25m

 

“These figures suggest that the stopping distances taught to new drivers in the Highway Code fall woefully short,” Brake spokesman Jason Wakeford said.  “Even though car braking technology has improved in recent years, the majority of the overall stopping distance at most speeds is actually made up of the time taken to perceive the hazard and react.

 

“The research shows that average thinking time is more than double that set out in the Highway Code.  A true understanding of how long it takes to stop a car in an emergency is one of the most important lessons for new drivers.  Understanding true average thinking time reminds all drivers how far their car will travel before they begin to brake - as well as highlighting how any distraction in the car which extends this time, like using mobile phone, could prove fatal."