What can also be included as examples of why risk compensation (RC) should be regarded as important with regard to safety on the road, are the following:

1. Long term RC. As well as the immediate adverse effects of seat belt legislation (and other forms of idiot-proofing the car or road environment for motorists), we have a long term effect. This is essentially a cultural phenomenon whereby the assumption of “safety” for car occupants decreasingly becomes about careful driving, and more about securing a “safe” car (seat belts, crumple zones, air bags, ABS , collapsible steering wheels etc.) and a “safe” road environment (central reservation crash barriers, cutting down roadside trees, making lamposts collapse on impact in ways which minimise danger to car occupants etc.).

All of these changes which have occurred since WW2 are forms of idiot-proofing which have a cumulative adverse effect on the safety of those outside cars. This cumulative effect is not simply observable in terms of time-series analyses which show the adverse effects of specific interventions such as seat belts, but manifests itself in a less tangible, but nevertheless definite, effect.

So, for example, would the antics of the likes of Jeremy Clarkson be as acceptable as they are in today’s safety culture if we had the cars and roads of the 1950s? I think not.

2. There is a definite POSITIVE manifestation of RC. In the same way that road users become less careful when adapting to a reduced perception of hazard, they can become more careful when confronted by an increase in hazard.

So, for most motorists, the increased presence of pedestrians and cyclists (seen as a sort of “hazard” insofar as crashing into one is generally thought of as undesirable, whatever the opinions of motorists about either or both groups of road user)can have a POSITIVE effect.

This positive effect can be seen on the (retrospectively calculated) casualty rates - casualties per journey or distance travelled by cyclists - when numbers of cyclist increase. This phenomenon among cyclists is referred to as “critical mass” or “Safety in Numbers” and has been seen dramatically in London over the last decade.

It has also been seen with pedestrians in street environments where elimination of traditional “safety measures” in “shared space” or “naked streets” has led to motorists being compelled by the sheer immediate presence of pedestrians (where speeds have reduced as a consequence of,or in addition to, these measures)to behave more carefully towards them.

For evidence and further information on these phenomena, take a look at http://www.rdrf.org.uk , as well as this website

Safest car I’ve ever driven? 1962 Morris Minor - no seat-belts, huge steering wheel inches from your chest, skinny cross-ply tyres, and brakes about as effective as old-style caliper brakes on steel bike rims in the wet. So many opportunities to die!

I have also noticed risk compensatory behaviour in my own riding when with a helmet. Even though I know that the 1″ of polystyrene isn’t magical, won’t protect me from any but the most trivial of possible impacts, and certainly won’t deflect several tons of metal from crushing me like a limp bag of giblets, I’m almost certain that my riding when lidded-up is less cautious than with.