IAM and its public relations

[trashbat]

So as some of you might have seen, there's a news story doing the rounds about 20mph zones, and the IAM is at the centre of it.

One such example is here, and I quote:

The number of serious accidents increased last year on roads with speed limits of just 20mph, figures have shown.

Local authorities can choose to reduce speeds in areas where vulnerable road users are at risk by putting up new signs or introducing 20mph zones with speed humps and chicanes.

But statistics from the Institute of Advanced Motorists (IAM) reveal that serious crashes on 20mph roads increased by 26% last year to 420 and accidents causing slight injury rose by 17%.

Now the statistically inclined amongst you might immediately spot something wrong with this, but 20's Plenty have put it better than I can (whole thing is interesting but PDF warning):

IAM analysis of DfT casualty figures for 2013 show that as the total number of 20mph roads increases, so do the total number of casualties, but their conclusion that this is evidence of increased danger shows a woeful lack of understanding of statistics.

...

In fact, wherever 20mph limits have been piloted, on looking at the casualties in detail, councils have concluded that there was a positive effect on road safety and subsequently widened the implementation across most areas. Now 20% of the UK population live in towns, cities or villages where the Traffic Authority is convinced that 20 is plenty for most streets.The IAM conclusion is bogus and reflects a poor understanding of either the changing numbers and success of 20mph limits or basic statistics

Well, quite.

I can't help wondering what the IAM are up to. The (unstated?) aim seems to me to be to supplant BRAKE as the go-to body for the media on the subject of road safety, but it doesn't seem to be too concerned with fact or purpose whilst doing so.

The three stated aims of the IAM are these:

- To improve the standards of driving (and riding) on the roads
- The improvement of road safety or Greater road safety or The promotion of road safety (my note: WTF?)
- The administration of a nationally recognised advanced test

I can see what it's trying to do about #2. I don't think #3 really requires much beyond their continued existence. I can see less and less what they're doing about #1.

I'm also curious as to what extent the membership agrees with its current strategy, which appears to be complicit in reshaping the road system to cater to the lowest common denominator, rather than trying to raise that bar and assigning more value to individual responsibility. An implicit or explicit agreement with the latter is presumably why its members bothered to sign up and pass their tests. Should it be representing these people, or are they just there to provide the funding for its unshakeable mission?

[MrToad]

I'm not going to get into the second half of the question about the IAM's current direction, but would draw your attention to the Telegraph story on the same subject, which contains some slightly different info.

This bit seems to acknowledge the statistical pitfall, rather than falling straight into it: 'Experts said the casualty figures reflect the growing number of roads with 20mph limits, but also raise concerns about their effectiveness.'

The thrust of the IAM comments seems to be that 20mph zones don't necessarily stop accidents and injuries. It's a shame they couldn't have done some more subtle analysis though, and come up with a an answer for whether they make much difference at all, apart from turning huge numbers of otherwise law-abiding motorists into criminals.

[trashbat]

The Telegraph story is no better, as far as I can see. This is the actual press release from the IAM, and I think the point stands on that alone - the reporting isn't to blame.

In case anyone's missing the point, what was the increase (in either network mileage or driver hours spent within) in 20mph zones?

That's before getting into whether the average 20mph accident was less damaging than the average 30mph one.

[Ancient]

Or even whether the main reason for 20mph limits is accident/injury reduction.

[martine]

Or even whether the main reason for 20mph limits is accident/injury reduction.

+1

Mr. Toad and I have both been on the Bristol City Council (BCC) 20mph consultation panel over the last 18 months. BCC say the main reason for introducing widespread 20 limits across Bristol is not casualty reduction. They also explained that in the 2 trial areas set-up 3 years ago, one had a decrease and the other has an increase in KSIs.

[trashbat]

What was their reason? (I can think of several good non-safety ones, just interested in which it was)

[Carbon Based]

Perhaps a bit tangent, but has anyone seen any studies into air quality in 20mph zones with the proliferation of humps, bumps and pillows that accompany them?

Most residential streets are probably subject to fairly light levels of traffic so there may be nothing in it, but I'd be surprised if the brake/accelarate driving these calming measures help matters.

[jameslb101]

What was their reason? (I can think of several good non-safety ones, just interested in which it was)

Something to do with our red trouser-wearing twit of a mayor? Talking of PR, this about the only thing he succeeds at.

[MrToad]

As I understand it, the main driver was the fact that local councils now have responsibility for public health in their areas.

Their data suggested that the perception of speeding traffic was one of the main reasons people gave for not choosing cycling or walking, with their attendant health benefits. The fact that this perception wasn't backed up by actual evidence wasn't discussed.

In proposing the policy, it was acknowledged that air pollution would increase because of the reduced efficiency of vehicles at lower speeds.

It appeared that everyone at the council was fully signed up to the 'speed kills' agenda, so there was no possibility of an informed discussion about whether this was actually the best way to improve road safety. The fact that the policy was driven by health and 'quality of life' issues effectively neutralised any argument based on road safety or the criminalisation of safe drivers.

In reality, our influence was limited to getting a few more roads excluded from the scheme than was originally intended.

[waremark]

In reality, our influence was limited to getting a few more roads excluded from the scheme than was originally intended.

Very well done.

[trashbat]

Thanks for the explanation. It's probably also a tangent but from a resident perspective, generally I'm comfortable with certain 20mph schemes. I don't have much if any experience of driving in Bristol but in the busy and claustrophobic residential streets of Portsmouth, on average a maximum of 20mph is probably about right.

I don't know what the effect is, because it's hard to quantify at the best of times, plus I don't know what the compliance is. I suspect noise levels are improved for one, and it serves to exaggeratedly highlight antisocial driving. If perception of safety or quality of life is improved, even if the hard facts don't support it, then that might still be a meaningful benefit.

On the other hand, I know of some completely useless and even harmful applications of it. Hello, Lancashire, I'm looking at you.

[TheInsanity1234]

To be quite frank, I suspect a 20 zone wouldn't make any difference to the actual speed of the traffic travelling down narrow residential streets, as I would hope that the average driver is capable of recognising the added danger of narrow residential streets

What does get on my wick are roads that I would consider to be safe at 30, perhaps 40, being given 20 limits.