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


If you read the article and the link in the article then yes they have.


This is a good analysis of the Bath report. tl;dr: The report was statistically incompetent and its conclusions are biased. https://medium.com/@lewisspurgin/20mph-zones-are-not-causing-more-deaths-37d41e30e297


This report has been widely shared here, on the other topic where we responded to it, and also in Hilary’s article.

It claims the Bath council report results aren’t statistically significant. It also claims the choice of control area was bad. Which is interesting. The accident rate was high in the control area. If a different control had been chosen, the results for 20mph zones would have looked even worse.

It may be the case that there’s not a statisticially significant worsening of accident rates in the 20mph zones. But accident rates have worsened in 7/13 zones, and improved in only 2/13 zones.

What is clear is that the 20mph limit in Bath has not made roads any safer so far.


I’m afraid I’m not going to waste my time on this one.


This isn’t true either. The number of accidents in a given period of time is going to vary due to factors having nothing to do with ‘Safety’ (and possibly randomnes) explaining at least some accidents. Therefore this conclusion cannot be reasonably drawn from numbers cited.


@Beige, perhaps I wasn’t clear enough in my post.

The point is this:

  • We may not be able to conclude from the Bath study that 20mph limits reduce safety (due to insufficient data).
  • We absolutely cannot conclude from the Bath study that 20mph limits improve safety (due to insufficient data, and obviously due to the number of serious accidents increasing in 7/13 20mph zones, and improving in only 2/13)


I have lost the purpose of the poll


What’s interesting about this poll is how it was converging on a similar result to the Tower Hamlets 20mph Zone opinion survey over the first few days, and then in the last 24 hours or so the results changed radically toward favouring 20mph.

Interesting :thinking:

Of course this is just a straw poll, and the results will be affected by who is invited to participate, and why.

Next time we do a poll like this, I’ll make sure it’s in the #lounge. This will help keep the sample representative of local people. I’ll also close the topic to replies in cases like this, to avoid people lashing out at others.


The poll remains open to votes.