Want safer streets for cycling? Make cars crashier


The risk thermostat theory – that humans take more risks when they feel safer, think ABS brakes, auto airbags – has been around a long time but is still controversial in some quarters.


The famous quip that motorists would driver safer if their steering wheels contained long spikes may be disputed by some epidemiologists but there’s anecdotal back-up for the concept on a motoring story on BBC.co.uk today.

Adrian Chapman from the 2CV Club of Great Britain said:

“If you are going to get hit by a lorry in a 2CV, then yes, it is going to hurt. Just not as bad as being on a bike. But as a result, you just drive more safely in a 2CV, you don’t get any of the false security you can get in a big modern car.”

In 2005, Edmund King of the RAC Foundation – who gets around London on his Brompton – said of the spike theory: “Of course, drivers with spikes would slow down, but accidents still happen. The driver with the spike might be very careful indeed, but that would not stop someone else crashing into him.”

Of course, extend the logic and the system works better: it’s not just one car fitted with a spike, it needs to be all cars.

The risk thermostat theory – also known as risk homeostasis or risk compensation – is expounded on at length in the classic and accessible book on the subject, Risk by John Adams.

Adams cites motorcyclists as a good indicator of the theory in action. He asks them to visualise riding in full leathers and helmet, and then he asks them to visualise riding the same journey in shorts, t-shirts and no lids. Guess which scenario sees the motorbikers going slower?

Adams has a blog: he summarises his views on risk compensation thus:

“Trapeze artists with safety nets, rock climbers with ropes, cricketers with pads and helmets all take risks that they would not take without their safety equipment. Motorists with seat belts, the road accident statistics tell us, do likewise.”

Seat-belts don’t save lives? What heresy is this? Read Adams’ views on this hoary old topic for yourself here, and think about this when well-meaning cycle helmet compulsionists cite the efficacy of seat-belt laws as their key argument in forcing all cyclists to wear helmets.

For the record, and as stated here, I’m pro-helmet, anti-compulsion. I also wear a seat-belt when driving. But I don’t scream around city streets in my car, using ABS braking, airbags and crumple zones as reasons to think I’m safe, bugger those outside my exoskeleton.