Monday, 15 July 2013

Our AM writes "20mph limit won’t necessarily work for Putney"

Over on the excellent website, our local London Assembly Member posted a comment earlier today.

His perspective raised a number of queries, which I've put to him and have copied below:

Why would a London-wide 20mph speed limit in your view simply be unworkable? In the past 30mph was the default speed limit with differences for other major roads, how would a 20mph speed limit be different?

I quite agree (with our AM) that the speed limit if amended to 20mph should be done with local resident support. Why can't we follow the lead of other boroughs which are consulting borough wide as to what people's views are? 

With regards to policing and enforcement, stretched local police budgets have resulted in very little enforcement taking place of the current speed limits. Perhaps we could explore community-led enforcement options? 

Given that Wandsworth Council now has direct responsibility for public health, given the positive indicators of our local trials, would it not make sense to look to roll this out across the borough, with local support via a borough wide consultation? 


I've had a prompt response and the key factor according to our Assembly member as to if 20mph can be workable depends on enforcement, be that via the police, or using cameras. This view contradicts the locally gathered evidence in Wandsworth of the two trial 20mph areas, which have seen a drop in the average speed in those areas without (to my knowledge) any further enforcement than that which is done for the roads normally. 

Our council is working on a strategy on 20mph limits for Wandsworth at the moment. If you would like to know more, Wandsworth Living Streets are organising a public meeting happening this Wednesday 17th July, at The Alma Pub. Cllr Russell King (Cabinet member for Transport) will be speaking on a range of issues, so do come along if you are free:

Wednesday 17 July, 7.30pm
The Alma Pub, Upstairs function room, 
499 Old York Road, 
SW18 1TF

1 comment:

  1. Quite so on enforcement. You might point to the experience of cities like Portsmouth. There, they have had an almost blanket 20mph limit for about the last five years. If you looked at Portsmouth on Google maps, basically any road which is not coloured on the map is 20mph. Most of the rest are 30mph.

    Anyway, the police don't enforce the 20 limits but average speeds have declined since the implementation. They are not down to 20mph, but they are in the low 20s and, more importantly perhaps, the 85th percentile (the speed below which 85% of traffic is moving) has fallen faster. I have no evidence for this, but I suspect that the average has fallen more than the median has, precisely because the numbers driving at the highest speeds have fallen the most.

    No doubt that is partly down to a cohort effect - if the car in front is doing 20 in a crowded street, you are basically going to have to do the same, and there may be a majority of speed infringers but the minority is large enough to have an effect.

    It is also interesting to note how Pompey drivers behave on the roads which are subjet to higher speed limits. For example the eastern access road, from the A27 down to Southsea, is dual carriageway fo most of its length and has a 50mph limit but traffic generally moves around 40. The traffic lights appear to be phased at about 40 and Pompey drivers are evidently more sensible and thoughtful than most, in apparently understanding that it is waste of time to hammer along between lights and wait longer at the reds. In fact, there is a relaxed unhurriedness of Pompey drivers which is in marked contrast to London, even if just occasionally, wearing my motorist hat, it (guiltily) frustrates me. I do wonder whether it arises from their habituation to slower speeds generally.

    You hear plenty of objections to 20 limits such as that people are not used to it, and have to watch their speedo and not the road. OK, why does the same not apply when driving at 30, or 40? Because you can tell how fast you are going, within a reasonable degree of accuracy, from visual and aural clues. You recognise the clues for 30 and 40 because you are familiar with them. Widespread 20 limits, and the same will soon apply. Another objection is that the road feels safe enough at 30 and drivers simply won't be able to hack crawling along at 20. OK, so how come really quite a lot of fdrivers can hack doing 30 on a road whose conditions are safe enough - for the driver - to drive at 40 or even faster? (I am talking about width, straightness, sightlines etc, rather than whether a cyclist will appear ahead, or a child run out into the road in front of you).

    So, 20 will take a little getting used to, if only because you are not familiar with it yet, but in no time at all you will get the hang of it and slow down. You will need no more radar speed traps than we currently need for any other speed limit.