SafeSpeed wrote:
I have overstated my position. I think it does to some extent would be more accurate.
Many modern safety features are 'invisible' to drivers and cannot be expected to drive a risk compensation cycle.
The 'Munich Taxi' study produced strong evidence of risk compensation behaviour caused by ABS brakes.
I don't believe that general improvements in refinement (smoother / quieter / faster) trigger risk compensation effects because after two weeks in a better vehicle it just feels 'normal'.
It's complicated stuff. I'm sure it's real and deeply subconscious - part of the human condition.
See what you think of John Adam's paper, or search out 'Target Risk' by Wilde.
It's something I've heard about many times in the past. The first time I remember it being mentioned to me, someone called it "risk homeostasis" - which I thought was a good term!
There are plenty of studies on the 'net suggesting that ABS makes people take more risks but there are also studies that show the opposite IF it is combined with knowledge of how the system works and its limitations. Back in 2000, our own DfT commissioned a study by TRL (I only have the abstract) in which 80,000 owners of "P" registered cars were sent questionnaires and 21,000 responded (so a reasonable sample size)!
The results showed that driving an ABS car was associated with:
16% fewer accidents amongst men up to 55 years old
18% fewer accidents amongst women
10% MORE accidents amongst older men.
There were also statements like:
"amongst men up to 55 years old, drivers ignorant of ABS reported the same number of accidents as drivers of non-ABS vehicles i.e. knowledge reduced accidents".
Now what I DON'T know is how they compensated for confounding factors - for instance, in the mid 1990s, it might have been fair to assume that the higher performance cars were most likely to have ABS and be driven by men - faster. It would also be fair to assume that those who knew about ABS probably also knew more about driving in general and how cars work and took more interest in what (and how) they drove -therefore having fewer accidents.
I haven't quoted all this to try and prove that ABS makes things better - merely to agree with you about how complex this sort of study is and how carefully the data needs to be sifted to weed out the confounding factors!