Darker Nights: 20mph Widens Fields of Vision and Halves Stopping Distances to Effectively Mitigate Risk At Source

Clocks go back Sunday 25 October meaning darker nights. Sunset will be from 4.45pm and nightfall from 6pm.  20mph limits widen drivers’ fields of vision. This helps see hazards and take avoiding action earlier. Drivers can stop in half the distance compared to 30mph. 20mph reduces the kinetic energy with fewer deaths or life changing injuries.

The Autumn change in clocks is a recognised road safety risk point. It’s usually met with an increase in messaging to light up or wear special reflective or lighter clothing to be seen. Yet, driving slower and 20mph limits is the most crucial and cost-effective long term change to improve road safety. 20mph is what the UN and WHO recognise as best practice in duty of care to vulnerable road users. 30mph is not fit for purpose where motor vehicles mix with pedestrians and cyclists regularly.

Yes, fit working lights on bikes. However, drivers should always drive at a speed at which they can adequately see and respond to any vulnerable road users regardless of what colour clothes they wear.

Recognise that drivers in fast, heavy vehicles pose the danger. The most evidenced and cheapest way to mitigate risk is to permanently reduce road speeds in settlements to 20mph (30kp/h). 20mph reduces fatality risk by a factor of 7. Every 1mph slower average speed in urban areas results in 6% fewer casualties. Driver’s fields of peripheral vision widen when going slower[1].  Stopping distance falls from 23m to 12m.


Ask your Councillors for wide area 20mph for a safer, better quality of life for everyone. 

Anna Semlyen, Campaign Manager for 20’s Plenty for Us commented:

“Darker nights pose road safety risks. It’s one of many reasons global road safety experts and the UN[2] say that 20mph or 30km/h should be the norm where road space is shared between motor vehicles, pedestrians and cyclists.  20mph limits help drivers see with wider vision with the time and space to take action to avoid hazards. Surveys show 70% of the British public say 20mph is the right limit for residential streets. Politicians with the power and responsibility to set the correct limits should recognise that 30mph is no longer fit for purpose and make 20mph the norm. Their constituents know that it’s the right thing to do. It’s a popular policy that makes a real difference to our quality of life.”

[1] https://nacto.org/publication/urban-street-design-guide/design-controls/design-speed/

[2] http://www.20splenty.org/un_says_20splenty

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