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CityCyclingEdinburgh Forum » Infrastructure
"Edinburgh councillors approve 20mph plans"
(423 posts)- Started 9 years ago by spytfyre
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Posted 4 years ago #
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Cords are fine, its specifically red cords that mark you out as a stereotypical New Towner. Even better combined with a labrador and some tweed.
Posted 4 years ago # -
This looks promising:
Average speed cameras could be installed on 25 roads in Edinburgh, police have confirmed.
https://www.bbc.com/news/uk-scotland-edinburgh-east-fife-49580270
Posted 4 years ago # -
There have been traffic monitors on the racetrack section of Corstorphine Road for the last few weeks: wonder if they are to do with this?
Posted 4 years ago # -
Cue howls of protest about infringement of human rights and nanny state and so on...
Posted 4 years ago # -
Not forgetting "Snaring otherwise law-abiding citizens"!
Posted 4 years ago # -
WAr on thE MOToRisT
Posted 4 years ago # -
Wish the article had included the safety record since the cameras were installed.
I had a look at crashmap.co.uk, and there were apparently zero injuries on that stretch of road during 2018. The previous record for a year was 5, with the average between 1999 and 2017 being 9.7/year.
From ~10/year to zero.
Posted 4 years ago # -
How is the record lower than the average?
That road still needs a toucan crossing into Inch Park from the castle path park. (as well as segregated cycle lanes in the longer term)
Posted 4 years ago # -
How is the record lower than the average?
Sorry - 5 was a record low. Highest was 16.
Posted 4 years ago # -
“Evaluation of the 20mph speed limit roll-out, to be considered by the city council’s transport and environment committee on Friday, has assessed the impact of the limit reduction on speeds, road traffic collisions and public attitudes. But the findings have revealed that monitoring of the 66 sites surveyed showed speeds dropping by an average of 1.34mph and up to a high of 2.1mph in some areas”
No quote from Nick Cook. I’m assuming he’s away.
Full report here:
Quick skim suggests:
- statistically significant fall in speeds
- large reduction in collisions
- reduction in severity of incidents and injuriesPosted 4 years ago # -
The average speed reduction is a meaningless figure to me. What does it mean in terms of the risk to me when I cycle or walk? A bunch of people doing 20 outwighed by one guy doing 40 or lots of people doing a solid 22? No idea.
Table 5 in Appendix 1 of the report is far more illuminating.
There has been a 40% reduction in vehicles travelling over 30mph (17% -> 10%) and a 25% reduction in vehicles travelling over 24mph (55% -> 41%).
A bit more interesting and encouraging than a completely opaque average speed figure.
Would be interesting to dig a bit more into the data. I wonder how the Table 5 data varies by time of day and location, for example. Also, where are the best and worst locations for speed reduction? Could give a bit of a best-practice nudge.
Finally, I wonder how much the speed reduction is stratified into different cohorts of drivers. I kind of imagine there are 2 or 3 groups of drivers - your 'hardened taxi driver' whose behaviour hasn't changed at all and still does 50mph down Inverleith Place at 2am if he thinks nobody is looking, pulling up the average; your 'obedient' driver who sticks doggedly to 20mph; and a fuzzy middle of people who maybe don't quite do 30mph any more but can't quite handle doing 20. This might all blend into one mush, particularly given that anyone behind a 20mph-abider will usually have to do 20mph anyway, but would at least be interesting to prove that a zero-tolerence enforcement campaign for anyone doing over 30mph, say, might achieve big reductions.
Posted 4 years ago # -
I've always been convinced that collisions are due to the outliers on the road;
* Least experienced
* Drunkest
* Most upset
* Most tired
* Stupidest
* Most unwellI haven't caused many road traffic incidents but the ones I have caused were down to inexperience and tiredness. I really don't think an average is a good measure for road safety purposes.
Posted 4 years ago # -
Early days yet, but it's looking good. Nice to see a policy introduced, its effect scrutinised in a detail rarely ever seen and its effect found to be pretty much exactly as predicted for this point in time.
Nice to see 20mph being further rolled out to Cluny Gardens and Greenbank Crescent, after lobbying by residents. Everyone seems to like 20mph speed limits in Morningside...
Posted 4 years ago # -
If the 20mph limit (and other speed limits) were more actively enforced the average speed would drop. The issue is with enforcement which affects driving habits. That said, if there was a spike in number of points/tickets issued, there'd be a different headline with the same people mouthing off
Posted 4 years ago # -
Interesting tweet here from a driving instructor saying his new drivers take 20mph as standard
https://twitter.com/PhylMeyer/status/1181309625427214339
This for me was one of the strengths of the Mark Ruskell bill, that we'd be creating a steadily growing cohort of drivers for whom 20mph was the norm - and that would include some of those statistically most likely to be in a collision.
Posted 4 years ago # -
I also understand (from chatter on twitter rather than reading the report) that the figures cited for speeds are the median rather than the mean - much less likely to get skewed by the behaviour of a few outliers
Posted 4 years ago # -
@sallyhinch: the full report goes into a lot of detail about speed distributions. There was a 40% reduction in drivers going over 30mph for example.
Bizarrely I saw a Tory councillor complaining that these were provisional figures: yes, it’s an initial monitoring report *as they demanded*.
Posted 4 years ago # -
“a Tory councillor complaining that these were provisional figures“
So, are they looking for ‘evidence’ that 20 is too slow (for the convenience of drivers) or want to defend lawbreakers by rescinding ‘onerous’ restrictions?
Posted 4 years ago # -
Anyone seen any data on journey times being reported?
Posted 4 years ago # -
"median rather than the mean - much less likely to get skewed by the behaviour of a few outliers"
That could explain the small shift. Assuming 40% of drivers are incapable of using the accelerator other than as an on off switch and another 40% have reduced their speed to 25mph or under the median is perhaps only a reflection of the middle 20% of less of drivers.
Posted 4 years ago # -
The council is also reviewing all 40mph roads with a view to reducing to 30mph
Posted 4 years ago # -
Does that include roads that cyclists cant use (like WAR)?
Posted 4 years ago # -
Seems to:
"all 40mph roads within the City of Edinburgh Council’s boundary are being considered for speed limit reduction to 30mph as part of the 40mph speed limit review"
I suspect a speed limit review of the WAR will fairly swiftly reach a conclusion of "No, 40's fine", but hopefully the likes of Burdiehouse Road and Comiston Road can come down to 30mph.
Posted 4 years ago # -
I couldn't tell what "urban frontage" meant, so not sure whether WAR has any. I dislike the notion that cycling provision (ie red paint advisory lanes) is being put in to slow down cars, as if we have volunteered to be rolling roadblocks.
Posted 4 years ago # -
I think the mode* (most frequent) speed would be a better measure & less likely to be skewed.
*With speeds divided into 1mph increments (bins)
Posted 4 years ago # -
Here's the full distribution from the report. The modal speed went from a draw between 22mph and 27mph to a solid 24mph. I'm not convinced that's any more useful than mean!
Would be cool to get the raw data and superimpose the graphs. I am particularly interested in the area under the curve shaved off above 27mph. Looks substantial.
Another good way of looking at it would be in terms of kinetic energy lost from the average car...
Posted 4 years ago # -
Yeah, mode only works for a unimodal distribution. That thing has two peaks. Given the sample size, I'm assuming that it's a good representation of the real distribution and not due to sampling. So it's either a problem of high/ low traffic or a combination of multiple roads which have different speed distributions.
The difference in mean is probably as good of single figure summary as you're going to get when you have two distributions to be honest. A reduction in the mean (as long as it's not down to time-limited traffic) will reduce the incidence of the highest speeds too, especially as the distribution of speeds is one where variance scales with the mean, which I suspect traffic speed is (googled but couldn't find any good proper model for it).
Posted 4 years ago # -
hopefully the likes of Burdiehouse Road and Comiston Road can come down to 30mph.
This would be great. Except that Burdiehouse Road being 30mph would feel almost as unpleasant* as it does already. It's really a continuation of the on and off-slips of the bypass. It would need something much visual or speed cameraey to deter drivers from not taking the usual out of it, simply because the road is so wide. But the new junction halfway up the northbound side might be weight behind 30mph consideration. Other people tell me that it's not so much Burdiehouse Road itself, as the junction at the bypass, that makes them choose an entirely different cycling route southwards, such as winching their way up Kirk Brae† and then onwards up Lasswade Road.
And then there's Comiston Road, which has really no need to be 40mph. At all.
* except in a velomobile, which is quite capable of exceeding 40mph on the downhill bits! That said, I've done it loads on the Elephant Bike (et al) and not died horribly, though I've not outright enjoyed the experience either, so my 'unpleasance tolerance' must be rather higher than other people's.
† If someone chooses to ride up Kirk Brae and Lasswade, instead of going a more direct route, something is scaring the
[rule 2]out of them.Posted 4 years ago # -
Interesting that there are two peaks in the distribution. That could be due to the “strict obeyers” driving close to the limit forming one peak & the “drive at the limit plus 5mph” set forming the other.
Posted 4 years ago #
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