20mph & will it make a difference?

Photo by https://www.flickr.com/photos/edinburghgreens/



I had intended to write this blog post a while back, after requesting some data from South Wales Police.  Since then it has been announced that the 20mph speed limit is going to be extended to more areas of Cardiff:

Wales Online link

This follows a trial of a 20 mph speed limit in Cathys & Roath. Now there is lots of data to show that by slowing down cars from 30mph to 20mph reduces the severity of injury- the Guardian covers this in detail here

The problem, however, is that lots of drivers don’t change their behaviour within these 20mph limits. In fact, on 30 mph roads in built-up areas, 45% of car drivers exceed 30 mph and 15% exceed 35 mph. (Source).

So, surely, if we want to reduce injury- we need to enforce these 20mph zones, especially as they are in the most vulnerable locations (near schools, housing estates, parks) where people will be walking. Well, I asked South Wales police using a freedom of information request:


Please advise for each year over the past 3, the number of offences recorded where a vehicle has been given a FPN (or other penalty) for speeding within a 20mph zone

Their response?

There have been 0 tickets issued by Police Officers in the last 3 years*

Oh, well, looks like the police aren’t enforcing, what I would say, is the most important speed limit of all. If they aren’t going to police this speed limit- do they bother enforcing any of the others? What does this tell drivers? I’m very concerned that, although I totally support the roll out of more 20mph zones, when we look at the statistics in a few years time showing the same level (or even increase) in injury in these zones, critics will point to 20mph zones making no difference.


*there have been 537 tickets issued by speed cameras from Jan 2015 – Aug 2015.