Exclusive: things tend to have a greater effect on the world once they exist

I heard on the lunchtime news on Radio 4 today the shocking news of an increase in the number of people injured on 20mph streets. Back when there were fewer 20mph streets, fewer people were injured on 20mph streets, they revealed. Now that there are more 20mph streets, more people are being injured on 20mph streets. This road safety intervention, they concluded, isn’t working.

This watertight logic perhaps also explains why BBC News have been so quiet on the destruction of the NHS. Before the NHS existed, literally nobody at all died in any of the then non-existent NHS hospitals. Almost as soon as the NHS was created, people started dying in the newly created NHS hospitals. Clearly the NHS doesn’t work.

Members of the Association of British Nutters will no doubt be getting very excited about these numbers, but before they make rash recommendations they should remember that back before the British motorway network was built, there were literally no people injured on the British motorway network, whereas now that the British motorway network exists, there are lots.

I hope that the main elements of the astonishing innumeracy that went into the BBC story — the failure to put the raw numbers into any kind of useful context, either of the rapid growth in the number of streets with 20mph limits as it has become easier to set the limit (or their changing nature as 20mph starts to roll out beyond quiet residential streets onto busier high streets), or of the far higher number (and, more importantly, rate) of injuries and death on either equivalent 30mph streets or on the same 20mph streets before and after the speed was lowered — should be obvious. Needless to say, reducing speeds on a street from 30mph to 20mph cuts injuries, regardless of the entirely banal fact that those few injuries which remain will thenceforth be added to the tally for 20mph streets instead of that for 30mph.

So, mockery over,  there’s a more important point: should an increase in injuries, if there really had been one, automatically kill off further roll out of 20mph zones?

Those who dwell at the bottom of Bristol’s Evening Post presumably think so

It beggars belief that the council intend reducing the 30mph speed limit. A limit introduced when there was no such thing as MoT’s, ABS brakes, crash zones on the front of cars and good street lighting.

I can see no justification in spending this money and would dearly love to know who Bristol City Council think it will benefit? It certainly won’t be the youth, disabled or elderly.

James R Sawyer clearly thinks that the 20 zones must be all about safety, as he argues that his ABS brakes and crash zones are already plenty enough to keep him safe as he drives through Bristol at 30. But Bristol have always been clear about why they’re moving towards a 20mph city:

Councillor Jon Rogers, Cabinet Member for Care and Health, said: “…20 mph zones create cleaner, safer, friendlier neighbourhoods for cyclists and pedestrians. They are popular with residents, as slower traffic speeds mean children can play more safely and all residents can enjoy calmer environment.”

Slower speeds are not a simple issue of cutting crude injury statistics. They’re more about reviving communities which have been spoiled and severed by traffic speeding through them, reclaiming a little bit of the public realm that has been monopolised by the motorcar, and enabling liveable walkable neighbourhoods to thrive. Far from “certainly no benefit for the youth, disabled or elderly”, we know much — some of the research having in fact been carried out in Bristol itself — about the many adverse effects of higher speeds and volumes of traffic, and the loss of shops and services due to car-centric planning and living and the blight of high streets by arterial traffic, on the mobility of those most excluded from the car addicted society, particularly the young, the elderly, and the disabled. If they’re lucky, these people will be forced into dependency on those willing to help them get around; if they’re unlucky, they will simply be left isolated and severely disadvantaged. But of course, we don’t like to acknowledge the existence of the large numbers of people who are excluded from much of our society, culture and economy by our rebuilding the world with nobody in mind except car owners.

The injury statistics cited in the BBC News piece include minor injuries, which is most injuries at slow speeds — little things which don’t require a hospital stay. What are a few more cuts and bruises if it means that thousands of kids are free to walk to school with their friends instead of stuck inside mum’s car? Would we rather keep the infirm all shut up and sedentary with no access to the shops and the services they need, too intimidated by the anti-social behaviour of motorists to cross the road, than risk one person having a fall?

These strands can be tied together by the other piece of context that would have been worth including in the BBC piece: in the same year that injuries in 20mph zones increased, injuries to pedestrians and cyclists in general increased — in part because there are more to be injured. It has always been the case that the great road safety gains that successive governments have boasted of have been won mainly by making streets so dreadful that people find them too frightening, stressful, unpleasant, humiliating or ineffective to walk, cycle, or do anything other than sit in a secure metal box on. Start making the streets a little bit less awful and people return to them.

“The overall results show that ‘signs only’ 20mph has been accompanied by a small but important reduction in daytime vehicle speeds, an increase in walking and cycling counts, especially at weekends, a strengthening of public support for 20mph, maintenance of bus journey times and reliability, and no measurable impact on air quality or noise.”

Like cycle tracks, which people still like to claim increase car-cycle collisions (they don’t) despite before-and-after studies largely ignoring the fact that the point of cycle tracks is to widen bicycle use from the confident and quick witted to the people who were are otherwise too scared, stressed or insecure to do so, so invalidating the before-and-after study design, an increase in minor injuries after speed limit reduction, even if it were really to happen, would be far from proof of a failure.

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21 responses to “Exclusive: things tend to have a greater effect on the world once they exist

  1. While these reports are ludicrous in themselves for the reasons you state at the start of your post, note that three years ago, the Fietsberaad completed a study which showed that 30 km/h zones were not as safe as they used to be in the Netherlands. The reason ? While in some places the environment also causes slower driving, it’s simply not good enough to slap in a lower speed limit and do nothing else.

    I pointed out then that 30 km/h zones were being given far too much emphasis in countries which are trying to get something for nothing. Successful application of lower speed limits needs to exclude drivers so that pedestrians and cyclists have the roads to themselves. Where many cars will remain, pedestrians and cyclists need to be segregated from them.

    In the Netherlands, a third of the entire road network now has a 30 km/h (18 mph) or lower speed limit, and not all of these lower speed limits are in places where the cars have been excluded.

  2. The fear and speed merchants are getting restless. Good.

    • Yes, consider that some of our most iconic cities have abandoned 30mph as being innapropriate for most roads. They know the writing is on the wall and they don’t like it.

  3. brilliant piece, thanks Joe,

  4. One of the most staggeringly illiterate bits is the part about the “17%” rise in deaths in 20mph zones.

    This turns out to be, nationwide, a single additional person. Now, that’s still seven too many deaths in 20mph zones, but still, hardly a reason to get rid of 20mph zones.

  5. It’s so easy for the media to perpetuate myths and half truths. It is also necessary to ask the Bristol Council to make some effort to promote the benefits of 20mph speed zones. You quote the local councillor supporting the 20mph zones in Bristol which is fine and dandy. But it’s not enough. A positive and compelling media promotion campaign to highlight all the benefits of the new transport policy is necessary. This would go some way to negate the impact of the nay-sayers and dumb media stories.
    In NZ, when the Government plans to build a new motorway, its transport agency goes on a PR blitz. This is dressed up as consultation. But in reality, it is used as a platform to sell the (so called) benefits and distract from the negatives. To have a council supporting better transport policies is one thing. To get the general public to buy into it is another. It’s a job half done. Strategies to promote the new policy should be a part of the package.
    PS: Is there any plans to move into the 21st C and start using metric? As in 30kph?

    • I’m not sure Bristol need to have a PR blitz: 20mph limits are overwhelmingly popular with residents, whatever the increasingly irrelevant niche audience newspaper might think. Most of the naysayers in the newspaper are, predictably enough, far suburban and exurban commuters who live and vote in neighbouring authorities but moan about the council not doing enough to support their chosen lifestyle as they clog up other people’s communities twice a day.

  6. On several newspaper website there are reports where Police surveys (eg on Oxford) have been done on traffic and they find 1 in 5 and over of drivers are ignoring the limits there.

    Its so sad that people wont do everything they can to reduce the risks. Yet the idiots are looking for a confirmation bias to say “20 doesn’t work, look at all these dead people!” They fail to realise not just the bad science but also that faster vehicles do impart more force upon bodies.

    (currently attempting to write my own views on 20 at my blog – gawd its hard to find all the sources!)

  7. Perhaps the BBC’s own Radio 4 program about the misuse of statistics, the name of which escapes me just now, should do a piece on this BBC News item.

  8. David Hembrow, the last time I was in Amsterdam (unfortunately nowhere else in the Netherlands, as I was there for work, and not for long), I observed what seemed to be a significant increase in the number of motorbikes and large motorised scooters in the cycle paths. This struck me as extremely unsafe for cyclists, especially the most vulnerable such as the very young and very old.

  9. Members of the Association of Bad Drivers also believe it their right to break the Laws of Physics too. That fact that they are unable to do so, has no effect in discouraging them in this belief which only makes them all the more dangerous on the roads.

  10. Oh. come on, it stands to reason that 20mph streets are more dangerous than 30mph streets. Just like the Netherlands is more dangerous for cyclists than the UK is, because there are more annual cycle casualties there than there are in the UK per head of population.

    Our roads minister Mike Penning says so, so it must be true.

    BTW I think you might find that Portsmouth’s experience, a little ahead of Bristol, is substantially similar. The entire city moved to signed 20mph limits on residential streets, at a cost of about £350 per street (£400k in total, for a city with a pop of about 175,000). Average speeds on 20 streets did nto drop to 2o, unfortunately, but it did drop from about 27 to about 23mph. Might not sound much but each 1mph leads to about a 6% fall in incidence of collisions, and to an exponential fall in severity for pedestrians etc although admittedly the exponential factor in that speed range is not so steep.

  11. What you must understand is that the Bristol Evening Post and its associated website attract the most hardcore commentators on anything relating to transport.

    Any news item which mentions the dreaded word “cyclist” very quickly attracts 150 comments along the lines of “All cyclists are eevil rules-dodging anarchists who don’t pay road tax and probably just try to run down old people while they ride on the pavement” (mind you, a lot of the commentators seem to wish that cylists would just get off the road – how easy is it to fit wings to a bike?).

    Bristol may be a Cycling City, and is the only city I’ve cycled in so I can’t say whether it is better or worse than others, but cyclists here are the spawn of the devil as far as the vast majority of the commentators on the Post’s website are concerned.

  12. All good points. A further point to consider is what was the speed of the motor vehicle in the car/bike accidents? I would conjecture it was greater than 20mph. One also needs to ask what is the average speed in the 20 zones? Several police forces have admitted that they do not intend to enforce these speed limits. Consequently, it is highly likely that the average speed has not reduced significantly from when the same road was a “30”. For 20 zones to work, they must be enforced rigorously.

    • Should have deleted “car/bike” from the 1st sentence, as figures clearly include pedestrian casualties as well.

  13. Pleased to see some effort finally to enforce them:

    http://www.oxfordmail.co.uk/news/9860507.Police_clamp_down_on_20mph/?ref=rss

    Would love to see more forces do this. I keep reading that they have no powers to enforce them – clearly not true.

  14. Here in the Cycling City of Bristol, cyclists are really not very popular among the motoring fraternity.

    I think it is where there are so many people who do cycle (for transport/commuting) that we are visible – motorists have to take notice and they don’t like cyclists holding them up and stopping them getting to the next set of traffic lights.

    Luckily, though, except for that road rage incident with the bus last year, there are enough cyclists here that we have the ‘critical mass’ (geddit?) to not be forced off the roads or intimidated too much.

    But, have a look at http://www.thisisbristol.co.uk/Calls-police-crackdown-pavement-cyclists/story-16704358-detail/story.html for a typical Post article and typical comments.

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