Scottish Borders 20mph limit study

[Nigel]

Scottish Borders council put 20mph limits in just about every town and village last year for an 18 month trial.

A first round of traffic speed data is reported here:
http://scottishborders.tracsis-tads.com/conduit/borders

For the few roads I cross-checked the speeds reported match what I've observed as motorist, pedestrian and cyclist.

[Pete Owens]

Looks good

[Jdsk]

The Council's description:
https://www.scotborders.gov.uk/news/article/4042/preliminary_road_traffic_data_made_public_ahead_of_20mph_trial_consultation

Jonathan

[Bmblbzzz]

I'd say that's broadly in line with what I've observed several hundred miles to the south. People say 20mph limits "don't work" because the traffic still largely does over 20mph; but they certainly do work in that they reduce the average speed of traffic. I'm not entirely sure how they do this without enforcement, but I guess it only takes a few people to slow down a bit and those behind have to follow. Also it's really good that Scottish Borders Council recognize the benefits are not only about safety but increased "peopleness".

[Jdsk]

People say 20mph limits "don't work" because the traffic still largely does over 20mph; but they certainly do work in that they reduce the average speed of traffic. I'm not entirely sure how they do this without enforcement, but I guess it only takes a few people to slow down a bit and those behind have to follow.

I'm not up to date with the evidence, but IIRC there's an important difference between 20 mph limits and zones.

Jonathan

[Pebble]

It certainly has reduced speeds, when you do get someone who is driving close to 20 there is usually 5 or 6 cars all tailgating behind. Lorries seem to be some of the most observant of the speed limits whilst the class of vehicle who seems to be taking the least notice is Agricultural tractors, quite frightening when you have one of thse monsters a few inches off your rear bumper.

I hope they continue with it after the 18 months, makes it feel far more civilised. One thing I have noticed as a driver, when I'm now down in England how stupidly fast driving at 30 seems in a built up area

[Bmblbzzz]

People say 20mph limits "don't work" because the traffic still largely does over 20mph; but they certainly do work in that they reduce the average speed of traffic. I'm not entirely sure how they do this without enforcement, but I guess it only takes a few people to slow down a bit and those behind have to follow.

I'm not up to date with the evidence, but IIRC there's an important difference between 20 mph limits and zones.

Jonathan

That's interesting. I have to confess I'm not entirely certain what the difference is in this context.

[Jdsk]

"There are two distinct types of 20mph schemes; sign only 20mph limits that are indicated by speed limit signs only and 20mph zones, which are designed to be ‘self-enforcing’ through the introduction of traffic calming measures, e.g. speed humps and chicanes."

https://www.parliament.scot/S5_Rural/Research_evidence_20mph_bILL.pdf

Jonathan

[Bmblbzzz]

Thanks, I thought it was something along those lines. ISTR that (in England and Wales, might have been different in Scotland) until maybe 8 or 10 years ago, all 20mph schemes had to be "zones" with humps etc. Down here (Bristol) most of the city is now a 20mph "limit" with signs but no humps or chicanes; it actually works pretty well.

[Pete Owens]

I'd say that's broadly in line with what I've observed several hundred miles to the south. People say 20mph limits "don't work"

The whole 20mph doesn't work myth mainly comes from Police who tend to be the most vociferous obstructionists to implementing them. Historically they insisted that speed limits should be set according to speed that drivers chose to drive at. Long ago the guidelines for setting speed limits used to base the speed limit on the 85 percentile of drivers - ie the speed limit was based on the speed chosen by the most reckless drivers.

The result of this was that 20mph speed limits were only ever imposed on streets where traffic was already moving slowly. Which of course meant that those speed limits couldn't have an effect. The police would also reinforce the ineffectiveness by loudly announcing their opposition and insisting that they would not be enforcing the limits. Having acted to prevent speed limits being introduced in places where it could make a difference they then used that lack of a difference (caused by their own opposition to to setting limits that could make a difference) to argue that speed limits were ineffective. A self-fulfilling circular argument.

But that was all 15 years ago. A growing number of places are introducing town wide 20mph limits. And whenever they do they observe the obvious - that the speed reduction is greatest the further above 20mph traffic was travelling before the limit was imposed.

[Oldjohnw]

It is quite a challenge when many ordinary daily journeys have a bit of both England and Scotland. I am in full support of the regime.

[thirdcrank]

For the last decade or so, local police priorities have been set by locally-elected police and crime commissioners and IIRC before they got going, I recommended on here that they should be lobbied over concerns like this. I get the impression that that has simply not happened on any significant scale so police resources and effort have inexorably been switched from things like traffic policing and into investigating other things. For the greater part of that decade, austerity ruled so those changes in priority were against a background of personnel reductions.

Boris Johnson has promised / aspires to a big increase in police numbers but only massive lobbying will cause any of them to be assigned to traffic policing.

FWIW, I've no figures and I'm not going looking for any but I suspect that speed enforcement - largely through cameras of course - is greater now than ever, in terms of numbers.

[Pebble]

Cameras really only catch those driving 'without due care and attention'. (if you don't see the camera you are not concentrating, and concentrating is most mportant whilst speeding). We need secretly hidden random cameras to catch speeders

[Jdsk]

Does anyone know the study design: any controls (other than historic) and any crossovers?

And is there any independent evaluation?

Thanks

Jonathan

[thirdcrank]

Re the Scottish Borders, I'm sorry if I've missed this but can anybody point me to an explanation of how this has been enforced? ie Has implementation been a matter of reducing speed limits and seeing how it pans out or have there been specific measures to enforce this?