20mph speed limit rollout by Lewisham Council (effective September 2016)


Main roads are for the movement of the majority of traffic volumes, smaller roads are mainly residential where people cross and children play.
The borough is already slowing down badly due to the borough wide 20mph, especially on more major roads. The last thing it needs is to be even slower.

The speed of large vehicles is always exaggerated by perception due to their large size and close proximity. I’m pretty sure most lorries are not doing much more than 20 around that corner.


Slowing traffic down or people’s lifes and safety…hm…what a choice.


If safety was the only concern worth considering, cars would be banned altogether. As would people walking on pavements without knee pads and elbow pads. This is about finding a sensible compromise that allows commerce and travel to continue whilst factoring in reasonable safety measures.


Far from it. I think that dangerous parts of the roads should have 20mph speed limit, like the one opposite WHSmith. No need to lower the speed limit everywhere, it will be silly. City and town roads are not motorways at the end of the day and drivers should be careful and considered when driving.


Some parts of roads, like the one you suggest, have naturally imposed speed limits, being the maximum speed it is possible to navigate the corner. As I say, larger vehicles are unlikely to occur exceed 20 due to the angle of the corner.

Speed is not a killer, the vehicle is, and the manner in which it is driven. Speed and stupidity are not the same thing. Sadly the latter is the the largest contributor to accidents.

While other countries raise and lower speed limits at what seems like 100 metre segments at a time, this is both costly and impractical. Of course lives matter. Given the footfall on that piece of road vs accidents, I would say it’s a pretty safe spot. Except for when idiots refuse to wait for the lights to change, or commuters play chicken 20ft from the crossing.

TfL do actually have a few sections of their RR which is 20mph, New Cross for one, but I get the impression that it is not an ideal at all.

While I despise the borough wide roll out of this limit, I can appreciate it is needed in some spots. The danger now is those too impatient to drive at that speed, recklessly over taking.

If any reconsideration is to be had, I would say it was to UP the speed limit back to 30 on certain roads, such as Brockley Rise through to Lewisham Way for example. Sadly I don’t think their assessment and adapt phase has this in mind for a second.


Just sent this to Lewisham Council… Same one I have reported a few times now.


Here’s a local poll by NewsShopper:

Curiously Lewisham Council aren’t publicly publishing the results of their consultation on 20mph limits in Forest Hill… :thinking:


not exactly persuaded by that. Is that the NewsShopper known nationally for its authoritative research studies or perhaps a different one? Agree it would be interesting to see local consultation outcomes but wonder how representative of wider opinion it would be. I’ll drop that national study here so we can see it on this thread. http://www.bristolhealthpartners.org.uk/latest-news/2017/10/16/public-support-for-20mph-limits-holds-firm-new-study-reveals/961


“However, approximately half of those surveyed agreed 20mph speed limits will be ignored by many drivers so are of limited benefit and that limits will not be policed or enforced effectively.”

What do we want? More ineffective and widely ignored measures! When do we want it? Now!


The question asked on that study was “do you support the introduction of 20mph speed limits in busy streets”

Not “do you support a borough-wide 20mph limit regardless of road type”

The study is barely relevant.


Seems entirely relevant. 64% supported introduction in residential roads. A large majority. I do not see why Lewisham residents would give a different result in a study of this type. And we learn that accident rates fall even with the 2mph small reductions in speed. And that likely compliance to limits claimed by drivers is increasing over time. These seem some good reasons to stick with this policy and keep monitoring these promising outcomes and driver behaviour.


The data collected from various 20mph experiments over the country has been patchy, and certainly hasn’t always supported the introduction of blanket 20mph limits.


The Manchester one is interesting and recent.
The reason I picked this up this afternoon is that you mentioned the 20mph limit is unpopular as though this were accepted generally and I did not believe this to be true. Among the general population we can now see it is popular - people want lower speeds where they live work and play, and that to me means residential roads too. I do get why many motorists don’t like it though.


More up to date data and interim analysis on the 3 yr national research for the DfT here for interest. http://www.pacts.org.uk/2017/08/atkins-research-on-20mph-limit-areas-interim-results/


As others have said, it’s completely ineffective without enforcement. As a driver, I hate driving up Perry Vale at 20mph with every driver behind me too close, hassling and trying to over take. As a cyclist I am alarmed by the speed that some drivers do on Perry Vale, definitely more than 20 and probably more that 30. It’s pointless having the lower limit if people know it won’t be enforced.


yes I share that experience both as a driver and as a cyclist. I remember some of the very earliest Perry Vale Assemblies where speed was identified as the major issue residents wanted to be addressed. We would have been happy with a 20mph limit but naively expected that it would be enforced in some way.

In Perry Vale I think I drive around up to 25mph - whereas before the limit I would stick at 30 ish. This sometimes gets me tailgated, but I reckon if I support the limit then I should act like it too - maybe I have some responsibility here, and can’t just look to others to make it happen. The more of us who make an effort, the more we can gradually influence others around us to accept this as normal. We know that this limit has great popular support. Why don’t I drive at 20mph ? Because like you I find that seems to induce some drivers to attempt unsafe overtaking. It’s my compromise I suppose.

My own behaviour change seems quite representative of the average driver. Nationally, one of the research studies mentioned above says that:- 'Evidence suggests 20mph limits result in a decrease in average driving speeds of between one or two miles per hour, and studies of speed limit reductions across the world imply that this reduction in speed would lead to a drop in collisions of between six per cent and 12 per cent.'
For me, that’s one very promising outcome, that is a very significant drop in accidents, with savings for the many agencies and families who get caught up in them.

I think it takes time for public health and social innovations to stick, and to get general public acceptance. Compliance with limits, new or old has never been 100%. There will always be drivers in a tearing hurry, people who just don’t care and late night boy racers. We had another quite serious looking accident in Perry Vale just a week or so ago, and from the look of the car damage I doubt the limit had any impact at all.

Reading around this, traffic management experts have considered evidence and different approaches. The most cost effective way of achieving a mass change in speed is to do signage only across all the roads - which is what Lewisham has done. If it is true that overall collisions are reduced by that amount, then it represents very good social value - in terms of reduced health costs, loss of life, injuries, jobs and so on.

Reinforcing limits through infrastructure (humps, pedestrian crossings etc) is very expensive, and it looks as though they can only be done on a small scale where there is a particular need. eg accident blackspots, rat runs. General enforcement does not look like a priority for the police…

There’s one other outcome that is quoted in these studies; that is though the average reduction is 1-2%. it is on the roads where much higher speeds were previously encountered that the biggest difference happens. In a road like Perry Vale that might mean something like an average of 35 mph before the new limit and somewhere under 30mph with the new limit.
This would be an improvement for the people who live work and play here.


Some more data just came in:

[Poll] Lewisham’s borough-wide 20mph speed limit

Chris, you forgot to quote the bit that says:

A nationwide review of 20mph limits published by the The Royal Society for the Prevention of Accidents (RoSPA) last month concluded: “A large number of evaluation studies have demonstrated a link between the introduction of 20mph zones and a subsequent reduction in casualties. The size of the reductions and the consistency of results over a wide number of areas are further evidence for this link.”

Does a nationwide study not trump a local study?


The article points out that the experience of Bath council and others “is reflective of the national situation.

And of course I respect that RoSPA may have a different take on the matter, but you forgot to quote the caveat about the RoSPA findings in the Telegraph article.

And I believe those RoSPA studies may be outdated, and they have since been forced to revise significantly.

This revision illustrates how inaccurate RoSPA’a studies have been, and how real-world data from Manchester, Portsmouth and Bath (all of which show a decrease in safety outcomes) should concern us all.


But one year on, a report has found that the rate of people killed or seriously injured has gone up in seven out of the 13 new 20mph zones.

Which means that in 6 of the 13 areas the rate has reduced. Although 7 is more than 6, it is hardly conclusive evidence and is based on a small area.

So far all that has been proved is that people, papers, and councils will pick and choose statistics that support their viewpoint. (referred to above as the Texas Sharpshooter)