A double-blind trial of 20mph speed limits is an excellent idea

Association of British Drivers chairman Brian Gregory had this to say: “As with most pet road safety ideas proposed by amateur enthusiasts – speed humps, speed cameras, etc, – there is little attempt to collect scientifically sound evidence of the benefit of such ideas. No proper controlled, “double-blind” trials are undertaken…“

Brian Gregory is absolutely right. Too many of our transport policies — everything from encouraging the wearing of bicycle helmets to attempting to “smooth traffic flow” in cities — are based on weak evidence and poor quality research, and many of them would benefit from well designed trials.

In particular, a proper double-blind randomised controlled trial of 20mph speed limits would be very welcome. I’m sure you can see how it would be designed.

First we take every residential neighbourhood in the country and split them randomly into “test” and “control” neighbourhoods. It’s double-blind, meaning that the boffins doing the stats should know only that there are two groups, and be “blind” to which one the test has been applied to until after they’ve finished crunching the numbers and determined which group of neighbourhoods came out best.

Then we give all of the test subjects (that is, residents, pedestrians, cyclists, children, the local economy, and anybody/thing else expected, according to the hypothesis, to benefit) the treatment — 20mph speed limits for their neighbourhood. Except that only those in the test neighbourhoods get the active ingredient; in the control neighbourhoods, they receive an inert placebo. It’s double-blind, meaning that these subjects must not know whether they are receiving the active treatment or the placebo.

The active ingredient, of course, is reduced speeds. So we have to implement the active ingredient in the test neighbourhoods while maintaining blinding amongst the test subjects. Easy enough, of course: fit to every vehicle a simple computer which recognises when it is in a test neighbourhood and limits the vehicle’s speed to 20mph in those areas. In the control neighbourhoods, the motorists should continue driving as they usually do at 35mph.

I’m sure that’s exactly what Brian Gregory must have had in mind, and it’s great to see the Association of British Drivers campaigning for this.

A simple question

I like Select Committees. They do a good line in scrutiny, as we’ve seen lately with the Media Select Committee’s hacking enquiry. On tuesday the Transport Select Committee sat to look at road safety, calling a representative of the Association of British Nutters as a witness.

The ABD made some assertions and MPs responded with the simple question: how do you know that’s true? You can see the delightful outcome at As Easy As Riding a Bike, with further comment at MCRcycling.

It reminded me of an exchange with The ABD on twitter — perhaps the event which first got the thin skinned ABD blocking its detractors on twitter. Back in July, the ABD tweeted something about average speed cameras on the extremely expensive new section of the A3 at Hindhead. @highburyonfoot, @jamesgleave1, and I briefly exchanged tweets speculating about why this Motoring organisation should object to average speed cameras. They said:

@TheABD Assn of Brit Drivers
@highburyonfoot @steinsky @jamesgleave1 Av Spd Cams encourage anal attitude to speed limit rather than attentive driving.
16 Jul Favorite Retweet Reply

There was some comment on this:

@jamesgleave1 James Gleave
@TheABD @highburyonfoot @steinsky in what way? Surely sticking to the speed limit is a part of attentive driving?
16 Jul Favorite Retweet Reply

@simon_bannister Simon Bannister
@TheABD @highburyonfoot @steinsky @jamesgleave1 Car drivers shld be a bit more anal IMO – self control, restraint, attention to detail etc..
16 Jul Favorite Retweet Reply

@highburyonfoot Caroline Russell
@steinsky (@jamesgleave1) @theabd have a v low opinion of drivers’ ability to judge speed, yet think cameras unnecessary as deterrent.
16 Jul Favorite Retweet Reply

johnstreetdales John Dales
I.e. @TheABD is for ‘drivers who THINK of (not for) themselves’ & ‘Attentive’ = above the law. Nice!
16 Jul Favorite Retweet Reply

The ABD were strangely silent on these questions. But I was interested in the far more basic issue: how do you know that’s true?

@steinsky Joe Dunckley
[citation needed] RT @TheABD: Av Spd Cams encourage anal attitude to speed limit rather than attentive driving.
16 Jul Favorite Reply

It turned out that this request for evidence was more difficult for the ABD to respond to than I had expected.

@highburyonfoot Caroline Russell
RT @steinsky: @TheABD [citation needed]. Where is the study that shows this? > perhaps @TheABD can circulate?
16 Jul Favorite Retweet Reply

@steinsky Joe Dunckley
two days down, still no evidence… RT @steinsky: [citation needed] RT @TheABD: Av Spd Cams encourage anal attitude to speed limit rather…
18 Jul Favorite Reply

@steinsky Joe Dunckley
Another day passes without evidence appearing… RT @steinsky: [citation needed] RT @TheABD: Av Spd Cams encourage anal attitude to speed…
19 Jul Favorite Reply

@steinsky Joe Dunckley
Oh gosh, is it really more than a week with no evidence already? RT @steinsky: [citation needed] RT @TheABD: Av Spd Cams encourage anal a…
24 Jul via web Favorite Reply

@steinsky Joe Dunckley
Oh, I wonder if @TheABD ever found that reference? RT @steinsky: [citation needed] RT @TheABD: Av Spd Cams encourage anal attitude to spe…
12 Sep via web Favorite Reply

They never did get back to us with their evidence for the claim that average speed cameras encourage inattentive driving. It’s almost as if it never existed…

Association of British Drivers “not a bunch of fanatics”

The ABD tries very hard but is often dismissed as a bunch of fanatics and speed freaks (which it is are not) [sic]. — Honest John

The Association of British Drivers — the group that is to mainstream motoring organisations what time cube is to mainstream cults — have made the shock move of saying something that isn’t totally batshit insane: the government should scrap £5k ‘gift’ to buyers of £25k electric cars.

It’s true.  If the government wants to meet its carbon targets and make the world a nicer place in the process, there are far more effective things it can do with the money than help buy toys for the rich.  While they’re at it, instead of funding EV charging infrastructure, there’s another kind of transport infrastructure they could fund that would make a much bigger impact…

Fortunately the ABD have saved their reputation for a laugh on every page with the excellent line “leaving aside the considerable doubt that CO₂ has any significant impact on climate change…”

Ah.  “Not a bunch of fanatics…”

Like most ABD press releases, the most coverage this achieved was to be churned on a couple of obscure trade press blogs.  Still, more than can be said for their previous comedy offering, which was ignored completely: 20mph too slow for Blackfriars Bridge.

Weekly War Bulletin, 19 June

Previously, Jag-driving cycle-fearing new Secretary of State for Transport Philip Hammond candidly told interviewers that his teenage son had asked him, “so, ah, what is the point of your job?”  Politics Home is now reporting that he has been candidly telling interviewers for The Spectator that not being a Lib Dem is the only possible reason he didn’t get a real job, the job of the moment, as Chief Secretary to the Treasury.  It’s almost as though he wishes he weren’t Secretary of State for Transport.  That’s one thing we’re all agreed on, at least. (Tip of the hat to Railway Eye)

However, the power hungry petrol head did find time amongst all the other Very Important Things that transport secretaries do to end the speculation over whether the new government would drop tools on Crossrail: they’ve promised carry on and finish the whole thing.  Just not said when by.  Presumably this means that it’s Thameslink upgrade, Great Western electrification, and HS2 that get cut instead.  (HT to London Reconnections)

Luckily, the economics boffins advising the government have developed a cunning plan for saving money on running trains.  It’s all about supply and demand, see.  If demand outstrips supply, you’ve got to do something to bring the two back into line.  The boffins suggest that the way to do that with rain travel is to rip out the seats.  Perfect!  Make trains even more crap and demand is bound to fall back into line with supply.  Even better, raise the fares by 7%.  If that doesn’t get ’em back in their cars, what will?

Meanwhile, we find ourselves unlikely allies of the Daily Mail, who report that even in the age of the economy drive there’s still one publicly funded ministerial limo left in Westminster.  It belongs to one David Miliband, who has been clocking up the miles on the campaign trail, and allegedly leaving it on the double yellows while he pops out for some hand-shaking and baby-kissing amongst the party members.

Also, pity the poor hard done by driver as there are more new calls for a reduction to the drink-drive limit — do check out the wonderfully vacuous and inarticulate statement from the not-even-entertaining-anymore Association of British Drivers, who were brave enough to take a stand against those who will take away the right of the humble Motorist to go out and kill somebody of a Friday evening.  And then there are the trials of countdown displays on pedestrian crossing lights.  These should be fun: pedestrians have been so well trained by drivers to think that the phase when the green man and the amber traffic light are both flashing is a phase designated for rapid acceleration of vehicles, and now traffic planners have decided to make the situation more interesting by re-training pedestrians to think that they can still safely step out into the road just at that moment when drivers are eyeing the amber light with their feet poised.

Meanwhile, in the provinces…

York has decided against having congestion charging, in favour of “improving public transport and making walking and cycling more attractive”.  Staff at Dulux are on standby for a large order of blue and red from the city council as I write.

Pavement cyclists in Norfolk.  Tut.  More on these later.

Look at these unsporting fellows in Manchester, installing average-speed cameras.  That’s basically a war crime.  Everyone knows that average-speed cameras take all the thrill out of speeding without getting caught.  The comments are, as ever, entertaining.

Cyclist rides naked through Suffolk village.  “We don’t have this sort of thing in Acton.”  Nope, I tellin’ ee, that’s the sorta nonsense them there folk up London way gets up to, with their disgusten by-cyclen ways.

Sustrans claims huge success in getting kids to cycle to school.  The people of Northamptonshire must be shocked and appalled.  There, the council’s opposition Labour group think it’s an absolute disgrace to suggest that kids should be doing something so dangerous as cycling, and want a stop put to it at once.

In Wales, man with mentally crippling micropenis condition desperately seeking some sense of purpose but running out of ways to try finding it.

And finally, secret recordings leaked from the BP boardroom, here re-enacted by actors:

http://www.politicshome.com/uk/article/9885/hammod_i_would_have_been_chief_sec.htmlPhillip Hammond