Bristol data showing walking & cycling is boosted by 20mph zones is ‘flawed’

Where I live I think there's only one 20mph zone, which is about 150 yards long. I've never seen any enforcement at that point (although occasionally there is a mobile speed camera parked 2 miles up the same road at a 30mph zone) and have no reason to believe it makes any difference to local driver behaviour.

Any benefit it might have for cycling is moot in any case, as the majority of roads around the whole area are completely geared in favour of motor traffic, despite the many local schools, and exceedingly unfriendly for both walking and cycling. Dual carriageways are impractical as cycling routes as they are virtual motorways and very indirect, and single carriageways are busy and narrow, often because of parked vehicles and the occasional bus.

we've had 20mph borough wide speed limit where I live (London Borough of Camden, NW London) since August 2013.

Police Commander admitted in interview with Camden New Journal (local newspaper) he does not have the resources to enforce this speed limit

every day, I seen numerous motorists speeding, red light gambling, jumping red lights, driving through green pedestrian crossing lights, driving at pedestrians trying to use zebra crossings, etc.

absolutely no traffic Police out there in LB Camden enforcing "the law"

other boroughs are campaigning for 20mph speed limits = TOTAL WASTE OF TIME WITHOUT POLICE ENFORCEMENT!

The comments from 20's Plenty do not endear me to their views, regardless of my vested interests as a road user. That's not a million miles from the kind of one-sided stupidity that states that if you have nothing to hide, you have nothing to fear...

Yesterday while driving I was over taken twice in a 30 limit and once in a 40. With no one to police it no one will obey it.

Looking at theABD's claims (and I did check them on their web site, as well

The ABD decided to investigate the figures because they did not tally with a Department for Transport (DfT) finding last January that there was “no conclusive evidence that speed limit changes in isolation from other measures have an impact on walking and cycling”.

Firstly, they don't deny there was an increase in cycling and walking just the weighting to come up with the headline figure.

I would agree you can't point to speed limits in isolation, infact that's the whole point. 20's plenty in conjunction with other measures helps make cycling seem safer and normal to non-cyclists which increases the numbers cycling (which they admit has happened) - obviously more infrastructure would be better.

He also criticised the data gathering, saying the 12-hour counts were undertaken on just one weekday and one weekend day , all in the summer schol holidays.

“Traffic counts are normally held outside holiday periods, due to their greater variability in levels of travel,” says Heymer.

Surely it depends what you are trying to measure? Most traffic surveys are aimed at measuring congestion of some sort or other, therefore you would measure in peak times - rush hour when it isn't a holiday.
Walking and cycling will tend to be more leisure based, and likely to take place when people have spare time. Obviously some of us commute by bike, but that's not necessarily were 20's plenty will have an impact.
So the timings seem reasonable.

Final gem from the ABD website
"ABD Welcomes Godfrey Bloom MEP as a Patron" -

tbh, you're doing bloody well to manage 20mph in central Bristol ... not sure the change in speed limits is going to make much difference at all.

Hasn't road.cc got anything better to do than quote the most extremist types of petrolhead fanatics?

The Duke of Wellington once said "Lies, Damn Lies and Statistics".

Put basically whatever set of figures you have, you can make them say anything you want them to.

For instance.
If 1 cyclist in 100 has a serious accident in a year and you have a cycling population of 1000 cyclists then you will have 10 serious accidents in year 1.
If the cycling population increases to 10 000 and the serious accident rate is 1 cyclist in 50 then you will have 200 serious accidents in a year 2.

So is cycling 20 times more dangerous or 50% safer? The raw figures could be used to support either viewpoint. And how do you measure things like "Do you feel safer?", "Does seeing more cyclists on the road give you confidence?"

Statistics are not science they are opinion.

My own statistically flawed research has found that motorists pay no attention to 20mph limits.

Both Camden and Islington have borough wide 20 limits and I'm routinely overtaken by vehicles when cruising at that speed.

It's pointless without enforcement. Once there is enforcement there may be a corresponding uplift in cycling and walking along with a reduction in collisions and injuries. Until then it's just signs, paint and wishful thinking.

ABD analysis shows 20mph speed limits alone not sufficient to encourage walking and cycling
ABD calls for councils to consider stronger measures such as lower speed limits, filtered permeability and pedestrianization?

Far greater scepticism needs to be applied to anything put out by the ABD than is on show here. They're a bunch of climate-change-denying, anti-local motorhead lunatics. This, for example, from their home page:

"The ABD calls for the use of sensible speed limits [not based on] vociferous local activists."

In other words, "sod the people who actually live there we want to scream through Cotswolds villages at 60mph"

The rest of their manifesto is the usual 'boo-hoo, us poor motorists' tripe you hear from people who don't have a clue how heavily subsidised they really are.

Death, frankly, is too good for them.

A biased organisation re-massages statistics to argue against lowering of speed limits. Not sure why we give these petrophiles oxygen

I could not give a toss frankly. On the estate I live going 20 has reduced speeds overall and does improve the quality of life on the estate.

20 is a very good thing. As a walker, cyclist and a driver, I am in favour of more. I cannot understand why some argue for faster speeds to be allowed on busy narrow urban roads with children etc.

I have a slight issue with the statement

"Should public funds be spent asking people questions we know the answers to, or on getting on with increasing safety?"

well, yes they should. Otherwise the same argument could, and at some point probably will, be used for mandating helmet use.

All you need to do is read any non-cycling specific website to see that 'we' want cyclist to wear helmets etc

its a dangerous precedent to set imho

If I went into Ladbrokes, and tried to lay a bet that reducing speed limits would ultimately reduce the severity of accidents statistically, they'd tell me,

"Sorry mate, we don't take bets on dead certs".

And yet we have a situation similar to that witnessed for decades within the smoking debate, where we all have to wait for many years before the opinions of so called "experts" gradually become perceived to be sufficiently bizarre that they eventually wither away, allowing a sensible 20mph limit to ultimately become the norm, rather than the exception.

The key to getting change is not to focus so much on the "hard to prove" reduction in injuries, but actually getting business to understand the link between slower speeds and higher trading figures. People understand money far more easily than safety, and if this approach ultimately achieves the same end much more quickly, then this is the strategy we should be using.

I'm no fan of the ABD, to put it mildly (its seems to be kind of a Jeremy Clarkson fan club) but its entirely plausible that the analysis they attack has statistical errors. Its quite commonplace for local authorities, lobbyists, corporations and governments to put out such things. They are always more concerned with whether the conclusion supports their argument than whether its statistically rigourous.

It wasn't in a peer-reviewed journal I am assuming?

But so what? I don't want cars zooming through my neighbourhood. And 20mph zones are nowhere near enough to encourage more walking/cycling, we need a heck of a lot more than that.

Though it sounds as if even the ABD guy is admitting that even this small measure, over this small time period and in this small geographic area did have a small but measurable effect in increasing cycling and walking (just not the implausibly huge effect the council reports).

So basically the motoring lobby want to be able to drive as fast as possible without having to look out for other pesky road users. What a surprise.

Well, if the 20mph limit did indeed result in more people cycling then it stands to reason that the absolute count of cyclist related incidents would go up.

You can bet your bottom dollar that, if the motoring lobby successfully argued the 20mph limit hasn't helped or, even worse, has caused things to deteriorate, leading to the 20mph limit being abolished, fewer journeys might then be made by bike and the commensurate reduction in the number of cycling related incidents in those areas would be crowed about non-stop by that same motoring lobby.

As the twenty's plenty spokesperson makes clear, an overwhelming majority support inner city 20mph limits. It's only the motoring-entitlement brigade who consistently come out against them and in this particular transport bunfight they are - for once - the minority voice.