[Closed] Blanket 20mph speed limit for Brighton

On a similar theme, "shared space" seems to be working in Poynton.
It's a bit long, at 15 minutes, but shows what can happen when revolutionary ideas are tried.

miketually - Member

All the evidence shows that 20mph limits do work.

With all due respect, that's utter horseshit.

MidlandTrailquestsGraham - Member

On a similar theme, "shared space" seems to be working in Poynton.

Shared space is a great, and proven idea. It forces (all) people to be responsible for each other. This leads to increased safety.
Removing responsibility decreases safety.

With all due respect, that's utter horseshit.

With all due respect, that's utter horseshit.

[url= http://www.bmj.com/content/339/bmj.b4469 ]British Medical Journal[/url]:

The introduction of 20 mph zones was associated with a 41.9% (95% confidence interval 36.0% to 47.8%) reduction in road casualties, after adjustment for underlying time trends. The percentage reduction was greatest in younger children and greater for the category of killed or seriously injured casualties than for minor injuries. There was no evidence of casualty migration to areas adjacent to 20 mph zones, where casualties also fell slightly by an average of 8.0% (4.4% to 11.5%).

20 mph zones are effective measures for reducing road injuries and deaths."

And [url= http://www.trl.co.uk/online_store/download_form/download_complete.htm?id=5097 ]the Transport Research Laboratory seems to agree[/url].

Both found via this [url= http://fullfact.org/factchecks/speed_humps_20_mph_limit_zones_plenty_Portsmouth_KSI-27588 ]fact check article[/url], which concludes (my emphasis):

[b]There is considerable evidence to support the view that 20 mph zones do reduce road casualties[/b]. Some of the more comprehensive findings actually suggest the effect is better at lessening the severity of accidents rather than the frequency with which they happen - possibly owing to reduced vehicle speeds.
...
[b]That there are casualty benefits when 20 mph zones are brought into action is well backed-up by the evidence.[/b]

With all due respect, etc.

It doesn't have to be. For example, build-outs can have a cycle bypass.

yeah trouble is what about all the residential streets with cars parked everywhere. Lots of councils seem very reluctant to reduce residential parking, residents might not be too happy either

Those streets should be self-calming.

"should"

miketually - Member

With all due respect, etc.

So how do you explain Portsmouth?
You know, the place where they introduced a blanket 20 mph limit and KSIs went up by over 50%?
I think the national trend was an increase of 2%, so you can knock a couple of points off if it helps. 🙂

Here's a StreetView of a street near me with build-outs like that on it:
http://goo.gl/maps/6bcbP

As you can see it is a 20-zone residential street that is long and straight. To the north it becomes an NSL as it leaves the village so drivers might have been tempted to go too fast on it.

The houses there have driveways for residential parking, so parking isn't a major issue and in my experience the build-outs work pretty well at calming the traffic.

(I don't think those are cycle bypasses on these build-outs by the way, I think they are just meant to keep the gutter flowing)

Shared access for town centre and residential streets is the way, make people think about every decision they make on the roads.

http://hembrow.eu/cycling/assenverandert.html

So how do you explain Portsmouth?
You know, the place where they introduced a blanket 20 mph limit and KSIs went up by over 50%?
I think the national trend was an increase of 2%, so you can knock a couple of points off if it helps.

More people walking and riding?

Are you saying you think lowering speed limits increases danger?

miketually - Member

More people walking and riding?

Are you saying you think lowering speed limits increases danger?

More people riding = increased safety, so it's not that.

I've already stated what I think; that removing people's responsibility decreases safety.

You know, the place where they introduced a blanket 20 mph limit and KSIs went up by over 50%?

Looking at raw figures like that is useless because it doesn't look at how many people were making journeys.

And looking at one year for a trend is useless, especially in a single city, because one major accident can cause a huge "rise" (e.g. one serious bus/coach crash could mean up to 80 more KSIs)

GrahamS - Member

Looking at raw figures like that is useless because it doesn't look at how many people were making journeys.

Then look at KSIs per mile driven; t'is the same.

And looking at one year for a trend is useless, especially in a single city, because one major accident can cause a huge "rise" (e.g. one serious bus/coach crash could mean up to 80 more KSIs)

You are right, but I don't remember any serious bus/coach crashes in Portsmouth that year, do you?

Just an example. Could also be a multi-car crash, roadworks, or an increase due to unusually bad (or good) weather that year etc etc

Absolutely.
I'm just a prevention is better than cure kinda chap, that is all.

I'm just a prevention is better than cure kinda chap, that is all.

Prevention = everybody stays at home and never leaves.

Although, 100% of domestic accidents happen in the home.....

sbob - Member

So how do you explain Portsmouth?
You know, the place where they introduced a blanket 20 mph limit and KSIs went up by over 50%?

[sceptical] really? [/sceptical]

miketually - Member

Prevention = everybody stays at home and never leaves.

Although, 100% of domestic accidents happen in the home.....

...and dwarf the number of accidents we have on our roads, just to keep things in perspective.

ahwiles - Member

[sceptical] really? [/sceptical]

Y, RLY.

Some things are hard to swallow when they go against what is to the individual, the natural and obvious conclusion.

For me, legalizing heroin sounds like an abhorrent suggestion, but get over the initial emotion and you can start to understand why it could work.

from the telegraph

which leads with the headline:

20mph limit has not made roads safer

In Portsmouth, the new, lower speed limit applies to all vehicles, at all times, on 94 per cent of the city's streets. It is not enforced by speed cameras or road humps, but relies on drivers to obey limit signs.

The analysis, carried out by the consultants Atkins on behalf of the DfT, found that prior to the reduction in the limit, an average of 18.7 people per year were killed or seriously injured on the streets covered.

After the reduction this rose to 19.9 per year.

Taking into account people with less serious injuries, overall road casualties fell by 22 per cent after the scheme was introduced.

so, not really.

wtf?

with decimal places like that in the stats, how many years has Portsmouth had the 20mph limit?

rounding up to whole numbers, is a jump from 19/year to 20/year just an increase of 1 due to the natural variation in accidents and numbers of people involved? or is it a significant 5.25% increase? with numbers like that, percentage increases/decreases are total b******s. one single incident could sway the stats by 50% just by a p155ed driver taking out a bus stop, and the next year a 50% improvement by that not happening.

More people riding = increased safety, so it's not that.

Increased safety for cyclists, as a percentage or per mile or whatever. But the number of accidents overall could still increase as you're still moving people out of cars and onto bikes.

Lots of councils seem very reluctant to reduce residential parking, residents might not be too happy either

At some point, people are going to have to wise up to the fact that a square of public highway to park your car on isn't a god-given right.

http://bamboobadger.blogspot.co.uk/2008/01/car-parking-ill-just-leave-this.html

(I've linked to this post before, but it's genius)

Increased safety for cyclists, as a percentage or per mile or whatever. But the number of accidents overall could still increase as you're still moving people out of cars and onto bikes.

Yep fraid so. Road injury rates are higher on foot or bikes than they are in cars - so getting some people out of cars can mean an increase in injuries.

(I don't think those are cycle bypasses on these build-outs by the way, I think they are just meant to keep the gutter flowing)

offs[/url] with cars when I've gone into a build out and they've driven in aswell blocking my exit, both sit there for a while shouting at each other. Ho Hum.

Build outs like all other road facilities need to be done right otherwise they endup being dangerous in other ways even if they do achieve their primary function.

At some point, people are going to have to wise up to the fact that a square of public highway to park your car on isn't a god-given right

so getting some people out of cars can mean an increase in injuries.

*like sticking 5p on a litre of petrol and suggesting people stick to speed limits.

trouble is build outs without a bypass can lower speeds but cause more aggro, how often do cars yield when you have right of way? IME not very

Not had any issues on that road - though usually I'm towing a double child trailer along there so cars tend to give me a wide berth anyway. 🙂

I agree it could be an issue - but if they were more common then drivers would soon learn.

but hopefully less KSIs long term

If you reduce car use then yeah there should be - but it is hard to make any significant dent in it. We are so unbalanced at the moment that 100 more people walking would be a huge percentage increase, but might not even be noticeable in terms of traffic volume.

it'll take a long time to convince some people. We're a car centric society top to bottom

I don't think this is entirely true. If you talk to people who are actually involved in urban planning then the focus is very much on getting people out of their cars, making towns and cities walkable, and all the stuff that the tabloid motoring columns sneer at.

You have to remember that around 50% of people in the UK don't own a car, and many car owners aren't particularly attached to them either. The Poynton video GrahamS posted above is an example of an ambitious expensive project that must have been pushed through over some pretty vocal objections, and if it can happen there it can happen in other places.

ahwiles - Member

from the telegraph

which leads with the headline:

20mph limit has not made roads safer

In Portsmouth, the new, lower speed limit applies to all vehicles, at all times, on 94 per cent of the city's streets. It is not enforced by speed cameras or road humps, but relies on drivers to obey limit signs.

The analysis, carried out by the consultants Atkins on behalf of the DfT, found that prior to the reduction in the limit, an average of 18.7 people per year were killed or seriously injured on the streets covered.

After the reduction this rose to 19.9 per year.

Taking into account people with less serious injuries, overall road casualties fell by 22 per cent after the scheme was introduced.

so, not really.

2010 - 92 KSI
2011 - 143 KSI

Care to dispute that?

2010 - 92 KSI
2011 - 143 KSI

Care to dispute that?

Are those figures for all streets, including those not covered by the reduced limit? What are the 2012 figures? What were the pre-2010 figures?

If 2010 was a particularly low year and 2011 particularly high it could just be a blip.

Taking into account people with less serious injuries, [b][u]overall road casualties fell by 22 per cent after the scheme was introduced[/u][/b].

sbob - Member

Care to dispute that?

i'm not looking to dispute anything, i'm just naturally skeptical, so i ask questions - like: 'are you sure?'

or simply: 'eh?'

and in this case:

where'd those numbers come from?

I got them from the internet. 🙂

link?

Here:

http://www.iam.org.uk/media-and-research/media-centre/news-archive/1087-road-deaths-and-serious-injuries-up-road-safety-spending-down

St Helens KSIs rose from 43 in 2010 to 73 in 2011

Stoke on Trent KSIs rose from 45 in 2010 to 71 in 2011

Portsmouth KSIs rose from 92 in 2010 to 143 2011

Coventry KSIs rose from 90 in 2010 to 137 2011

These were also the councils with the biggest increases/decreases in the KSI rate per billion vehicle mile.

So bugger all to do with 20 mph zones, and part of what could well be a wider national trend.

sTroll on, eh?

thanks for those very worrying numbers Mr A.

(although it seems the national trend is good, there are a few 'hotspots')

The national trend was a 2% increase, as already stated on this thread (possibly attributed to weather).

miketually - Member

Increased safety for cyclists, as a percentage or [b]per mile[/b] or whatever. But the number of accidents overall could still increase as you're still moving people out of cars and onto bikes.

Surely my bold is the only important metric?
Of course, 1 million cyclists will have more accidents than 100, but I'm certain (from many sources found in one of the helmet threads) that an increase in cycling leads to an increase in safety.

GrahamS - Member

Yep fraid so. Road injury rates are higher on foot or bikes than they are in cars - so getting some people out of cars can mean an increase in injuries.

But the more cyclists, the lower that injury rate is, and fewer cars surely means fewer car crashes?

I'm sure you're not, but it sounds like you two are trying to argue against cycling as a safe mode of transport!

The benefits of "safety in numbers" are actually a lot less clear than the CTC et al would like to you to think.

http://crapwalthamforest.blogspot.co.uk/2011/02/what-wont-bring-about-mass-cycling-6.html

Mr Agreeable - Member

The benefits of "safety in numbers" are actually a lot less clear than the CTC et al would like to you to think.

http://crapwalthamforest.blogspot.co.uk/2011/02/what-wont-bring-about-mass-cycling-6.html

If you look at a country like the UK, where there hasn't been a big enough increase or decrease in cycling to be statistically significant, then yes, it isn't that clear cut.

Ignoring bullshit blogs for a second though, and looking at the wealth of statistical data available using countries all over the world, it would certainly appear that increased cycling = increased safety.

Of all the places where I had imagined I would have to defend cycling as a safe and beneficial mode of transport, this wasn't one of them. 🙁

It's going to be hard for cyclists to stick to that speed limit

Increased cycling = increased safety? Or does increased safety = increased cycling? They're not the same thing.

Interesting that you mention other countries with high levels of cycling. In the Netherlands they have a default speed limit of 30 km/h in residential areas. Same in Germany. Just sayin'.

I live on a 30mph road where everyone does 15-20 mph.

OMFG PEOPLE ARE THINKING FOR THEMSELVES!!!

What is it about commies (that is, the general STW pop.) always wanting to dictate and be dictated to? 😕