You can blame the French for this one: the next time you buy a car it may well be packed with buttock-vibrating technology designed to keep you alert and thus reduce "common type of car accident by up to 15 per cent", the Telegraph reports.
The prang in question is rear-ending - accounting for a quarter of all accidents - and caused predominantly by pure lack of attention, which is reckoned to be the cause of a half of all road accidents. Accordingly, one Citroen model "already vibrates the trousers of drivers to warn them when they cross a lane too slowly, which suggests that they are falling asleep".
And if having your rear end agitated in order to avoid violating the guy in front's rear end isn't enough of an affront to civilised society, Oxford uni's Dr Charles Spence has been telling the British Association's annual shindig in Dublin of other ways that car manufacturers are looking to keep drivers on the case.
Spence says the industry is - despite "ever-more sophisticated sensors to warn of an impending accident" - unwilling to let computers carry out crash avoidance "because of legal reasons, for fear of being sued".
The solution, then, is to find ways of gently nudging the driver. These include the aforementioned use of touch, plus odours like peppermint to keep you perky and the preposterously-named "auditory earcon". The latter can include, for example, "linking the sound of a car horn to a location" which, according to a study coming soon to the Journal of Experimental Psychology, "encourages drivers to look towards a source of danger".
No, we have absolutely no idea what that's all about, either.
As regards vibrating car owners into consciousness, the Transport Research Laboratory in Berkshire has been conducting tests, the results of which will shortly be entertaining readers of Transport Research Methods.
The upshot of the TRL's study is that "a 200 millisecond improvement can be achieved in reaction time" and "an improvement of driver responses of about 500ms would reduce rear-end crashes by as much as 60 per cent".
So, there is some method to all this buttock-shaking madness. For his part, Dr Spence is examining the possibility of vibrating other bits of the vehicle, including the seat belt, pedals and steering wheel. Spence says that one Japanese manufacturers claims all cars will be fitted with tactile warning systems by 2010, so don't say we didn't warn you. ®