Julie Patten has done great work with her Freedom of Information request regarding traffic crashes in Kendal (Letters, November 5, 'Causes for accidents').

Julie wonders how useful a 20mph speed limit would be in reducing crashes. So does 20’s Plenty for Kendal and, of course, we can’t know with any certainty. But we can make an educated guess.

Between 2013 and 2015, thanks to Julie’s hard work, we know there were a whopping 115 collisions in town. Of those, 29 were due to a failure to look properly. So how might a 20mph limit affect those incidents?

If a pedestrian fails to look properly and steps out in front of a car doing 30mph, it’ll take roughly six car-lengths to come to a halt. At 20mph you can halve that to just three car lengths. That pedestrian has a much better chance of avoiding getting struck in 20mph traffic, for sure.

Another five of those 115 incidents were down to poor judgement, for example of oncoming car speed.

Researchers at the Royal Holloway, University of London, have found that primary school children cannot accurately judge the speed of vehicles travelling faster than 20mph – their judgment becomes unreliable once the approach speed goes above 20mph. So we can be confident that, for Kendal’s young children, the change to a 20mph maximum will reduce the chances of them misjudging oncoming vehicle speeds.

Fourteen of the incidents resulted from poor turns and manoeuvres, and problems at junctions. Indeed, Bob Swindle wrote to the Gazette on July 9, 2015 in support of 20’s Plenty for Kendal, citing just such difficulties turning in traffic on Sedbergh Road.

With a 20mph limit, filtering at junctions becomes easier, as smaller gaps are needed, so drivers are less likely to get impatient and risk-take. It is far easier for motorists to safely pull into traffic travelling at 20mph than at 30mph. Junctions work more efficiently and queues reduce.

We shouldn't forget that 20's Plenty is not just about road safety - although of course it's important. It was first suggested to address traffic congestion, and it will also make Kendal quieter, cleaner and increase walking and cycling in town.

20mph is not a cure-all – there will still be crashes in Kendal when 20mph is introduced. But just a moment’s thought tells us that it helps. And results from places where 20mph has already been introduced show it is very effective at reducing the number and severity of crashes.

Julie's research confirms what we already know - people make mistakes. And 20mph limits create a more forgiving environment where the consequences of those mistakes are much less serious - people not only feel safer, they really are safer.

So in answer to Julie’s question: how useful would 20mph be in eliminating car crashes? The answer has to be: very useful, very useful indeed.

Rory Black, Alastair Dunn and Paul Holdsworth

Kendal