John Adams: risk compensation
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• General Motors senior research scientist Leonard Evans has designed two hypothetical vehicles. One, which he calls an "invulnerability vehicle", is built like a tank with a padded dashboard. The other, dubbed the "death trap vehicle", is extremely flimsy and has a sharp spike sticking out of the steering column. He reports that safety experts fail to agree on which vehicle would be more likely to kill its driver — but they are unanimous that the invulnerability vehicle would be more likely to kill other road users.
One could compare Evans extreme vehicles to HGVs, buses and bicycles. HGVs are very safe — for their drivers. In 1985 54 bus and lorry drivers were killed in crashes, compared with 285 cyclists. Buses and HGVs, however, covered more than five times as many vehicle kilometres as bicycles, so for a given distance a cyclist is about 27 times as likely to be killed on the road than a bus or lorry driver.
By contrast, cyclists rarely kill other road users, while for every bus or HGV driver fatality, 18 other road users were killed by HGV or bus crashes. Which leads on to the question: what do we mean by 'safety'? For example, in the US traffic moves more slowly, on wider, less congested roads; cars are larger while pedestrians are better controlled. Yet American road users are twice as likely to die in a given distance than their British counterparts. John Adams concludes that while America is subjectively safer, it is objectively more dangerous. He sums up his view: "Something is dangerous if it has the potential to cause harm . . . something is safe if such potential is absent. Where danger is present, but accurately assessed and prudently dealt with, this potential is not realised. Thus accidents are a useless measure of danger or safety."
There is a theory of risk compensation that postulates a level of risk which individuals will accept, or even seek. So safety measures which reduce an activity's potential danger without altering people's tolerated risk will be nullified by behavioural reactions which re-establish the level of risk with which those people were originally content. There is statistical support for this theory. Since the beginning of this century safety regulations and enforcement have failed to reduce fatality rates. Instead the risk seems to have been redistributed, rather than reduced, and potential safety benefits have been consumed as performance benefits. Similarly, designating an area as an accident 'blackspot' reduces accidents at that spot — but increases them in the surrounding road network.
Pointing out that HGV and bus drivers, while reasonably safe themselves, are a potential risk to other road users, Adams wonders if that these drivers attitudes to safety could he modified.
"To be effective, such measures must be substantial — the psychological equivalent of the extra physical threat experienced by other more vulnerable road users."
Economic (dis)incentives must bear directly on the risk taker (the driver), possibly in the form of a substantial fraction of his pay being delivered in the form of a "no-claims" bonus.
Social (dis)incentives work by engendering pride in desired (safe) behaviour and by rendering dangerous behaviour shameful. It is important to lead by example. High risk-taking, macho managers are likely to inculcate similar attitudes in their drivers.
Legal disincentives in the form of stricter regulations, more rigorously enforced, are likely to result if the commercial transport industry itself does not attempt to redress the imbalance of vulnerability between its drivers and other road users.