New figures show Highway Code falls short on stopping distances

News from Brake
Tuesday 25 July, 2017

Stopping distances in the UK Highway Code should be increased because drivers' thinking time has been underestimated, according to figures obtained by Brake, the road safety charity.

Brake asked TRL (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 (see table 1).

This means that average total stopping distance − including thinking and braking distance − is an extra 2.75 car lengths (11 metres) 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.

Table 1: overall average stopping distances (average car length = 4m)



30 mph

40 mph

50 mph

60 mph

70 mph

Brake/TRL study







UK Highway Code















See a graphic showing the differences here.

Brake is calling on the Government to increase stopping distances in its next update to the Highway Code.

Jason Wakeford, spokesman for Brake, the road safety charity, said: "These figures suggest stopping distances taught to new drivers in the Highway Code fall woefully short. 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 a mobile phone, could prove fatal.

"Brake is calling on the Government to increase the stopping distances in the Highway Code as a matter of urgency."


Notes to editors:

Cuerden, R. (2017). The mechanics of emergency braking. Transport Research Laboratory:

About Brake

Brake is a national road safety and sustainable transport charity, founded in 1995, that exists to stop the needless deaths and serious injuries that happen on roads every day, make streets and communities safer for everyone, and care for families bereaved and injured in road crashes. Brake promotes road safety awareness, safe and sustainable road use, and effective road safety policies.

We do this through national campaignscommunity educationservices for road safety professionals and employers, and by coordinating the UK's flagship road safety event every November, Road Safety Week. Brake is a national, government-funded provider of support to families and individuals devastated by road death and serious injury, including through a helpline and support packs.

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Road crashes are not accidents; they are devastating and preventable events, not chance mishaps. Calling them accidents undermines work to make roads safer, and can cause insult to families whose lives have been torn apart by needless casualties.

Tags: road safety stopping distances thinking time 20mph 30mph Department for Transport Highway Code car lengths TRL Transport Research Laboratory research data