Friday, 30 November 2012

'Safety in Numbers' or a 'Target Rich Environment'?

'Safety in Numbers': the idea that by being part of a large physical group or mass, an individual is proportionally less likely to be the victim of an accident.

'Target Rich Environment': a situation in which an attacker is presented with a large number of vulnerable targets.

In the Great War, during 'Bloody April' 1917, novice British reconnaissance pilots were sent into battle after spending just a few hours learning to fly. They were given no training to prepare them for the realities of battle: they learned no combat training or evasion techniques - after all, they could barely fly straight - how could they be expected to learn to fight? Upon arrival at a front line squadron, they were simply given a helmet and ordered to fly their aircraft deep into enemy territory. There, they would form a defensive circle of aircraft, the rearward firing machine guns of each plane supposedly protecting the next - 'safety in numbers'! Veteran German pilots saw things differently - they saw a 'target rich environment' - and they took full advantage of the situation. As a result, the life expectancy of a novice British pilot might be measured in hours.

On our 21st Century roads, there are a few similarities. Novice cyclists are encouraged to get on their bikes with no training whatsoever. Most barely know how to ride. They have little clue as to the rules of the road, how to ride safely or how to avoid collisions with motor vehicles. They are told that if enough of them start cycling, their numbers will magically protect them - again 'safety in numbers'! Like the pilots of April 1917, they too are reminded to wear a helmet. As a result of the failure to properly prepare cyclists, there is a 'target rich environment' in which the roads are filled with vulnerable and clueless potential victims - and London's roads have become more dangerous for cyclists as a result.

Of course, the biggest difference between the situation in the skies above Flanders in 1917 and that of London roads in 2012 is that motorists aren't actively trying to harm cyclists (though there are exceptions). The vast majority of cycling casualties happen by accident, caused by a shared lack of competence and sense of entitlement on the part of motorists and cyclists alike. Motorists seem to think that the fact that they passed a driving test (sometimes decades ago) means they don't need to brush up on the Highway Code, while cyclists think their right to the road means they don't need to do so either. In general, both groups seem to think they can do as they like (as long as they don't get caught breaking the law). Both groups act as if their vehicles are toys. This attitude kills, and as long as it persists, no amount of supposedly 'safe' infrastructure, no amount of green, blue, yellow or white paint, no amount of segregation, no amount of rhetoric and no assurances about 'safety in numbers' will make any real positive difference.

The fact is, 'safety in numbers' doesn't work - at least, it hasn't during the last 5 or 6 years in London; a time when Transport for London and London's 'cycling mayor', Boris Johnson, have implemented a number of schemes intended to encourage people to cycle on the city's new segregated cycle lanes, paths and 'Cycling Superhighways'.

Here's what the Greater London Authority has to say about the situation:

"Our analysis in Graph 1 shows that the safety in numbers effect has not prevented an increase in the cycling casualty rate between 2007 and 2010. Therefore, there remains an imperative for the Mayor and TfL to make improving the safety of cyclists on the roads the top priority in all their cycling programmes."

Safety a top priority? Ya think? Well, that would be a change!

'Safety first' is, admittedly, a novel concept for traffic engineers. Maybe now they'll take some time to consider the actual evidence for and against segregated cycling facilities. Maybe the government will even spend some money teaching novice cyclists how to ride safely on London's roads.

Yeah, right! Who am I kidding?

So just as with the pilots of the Great War, today's cyclists will have to learn purely through survival. The longer they survive on the road, the better their chances of learning the integrated cycling techniques that will keep them safe. They must learn this alone because, according to today's brand of populist cycling advocacy, it's much more important to demonize car culture, to praise the health benefits of cycling and to support questionable infrastructure than it is to teach cyclists how to use the road safely. Like the British soldiers and airmen of the Great War, today's cyclists who dare to go out on the road are 'lions led by donkeys'.


  1. I'd not be so hard on traffic engineers. Actually, the traditional engineering societies (AASHTO, the folks who write the MUTCD) are the least likely to uncritically accept some of these newfangled designs proposed by the avante garde (NACTO) folks, which is why the avante garde folks formed their own society, NACTO. My own traffic engineer is very conservative in adopting new designs, but one criticism I have of the county is that it installs old designs with less critical thought to "what if..."

    Otherwise, could not agree more. Where I work, one is considered a fool to think that engineering controls, even good ones, used alone, will protect people. One has to be trained to understand and respect the engineering controls and work within their safety envelope.

    Where I work (in a facility that handles the actinide row of the Periodic Table) one does not casually ignore proficiency and rules--such a casual disregard of the rules as we see on the roads could lead to a very short career, if not life. Lots of overlap here with driving a vehicle. Both can cause harm if not taken seriously.

  2. IMO, there probably IS something to the safety in numbers theory. Motorists generally do not want to run into cyclists or anything else. If these typical motorists encounter cyclists more often, they simply get better at avoiding running into the cyclists, just as they'd get better at avoiding deer if they encountered deer enough for that to become routine. Neither the deer, nor most of the cyclists follow the rules motorists expect of each other on roads.

    As for the cyclists, I suspect that if there are more, it is entirely possible that a higher fraction have accumulated enough experience not to ride as if they were drunken children. WW1 pilots demonstrated the same trend.

    Of course, neither trend matches the Jacobsen hypothesis which was entirely unsupported by any real test of validity in his paper. He might as well hypothesized that the effect could be explained by pixie dust, except that would have probably not been accepted as "settled science" by the media.

    1. I agree that there probably is a 'safety in numbers' effect. The studies I've seen seem to bear it out. The problem I have with it is that it's used by 'bicycle advocates' as a reason to make their prime directive getting more bottoms on saddles. When that's the main thing advocacy groups care about, it tends to create a situation in which people come into cycling unaware of the need to learn the skill. In fact, I've been scorned by 'bicycle advocates' for suggesting that cycling even IS a skill. They seem to believe cycling is something that anyone is able to do well, but it never will be, because (as we know) there's a huge amount more to transportation cycling than being able to ride a bike.

      In terms of this blog post though, the thing is, in London, the 'safety in numbers' effect doesn't seem to be there. So if safety in numbers is a real phenomenon, it means the effect (which is always small) is being overwhelmed by some other force or forces. I suspect London's 'traffic smoothing' program has something to do with it, and I think the resulting higher road speeds may be contributing to the tendency for 'safety in numbers' to be morphing into the 'target rich environment'.

  3. My traffic engineer says something similar, Steve. There is apparently a "warrant" needed to put in a crosswalk, for example. A minimum no. of people must cross the street per some period to demonstrate a need. He explained it by saying if a crosswalk is never used, motorists assume there are no peds so they become complacent. So I am sure there is something to safety in numbers, i.e., if there is an expectation of seeing cyclists, motorists will notice them, just as there is an expectation up here to see deer jumping into the road at dusk. But I'd rather not have cyclists acting like deer. Sucks to hit a deer, too.