Theme: Places – Scene of the Accident

There are some places you simply don’t want to go.

Image: Motorauthority
Image: Motorauthority

In his transgressive 1973 novel, ‘Crash’, novelist JG Ballard explored a netherworld where a group of symphorophiliasts play out their fetishes of eroticism and death amid the carnage of motor accidents. But while most of us might find ourselves staring luridly against our better instincts at some roadside crumplezone, we recoil in dread from the blood and the bone. It could after all so easily be ourselves trapped and lifeless inside some shattered hatchback.

Safety never sold cars. A man said that: after all, women are far more sensible when it comes to such matters. I’ve made a joke on several occasions to the effect that in over thirty years of holding a driving licence I’ve never been seriously killed in a car. Ha-ha. But let’s be honest, it only needs to happen once. Black comedy tends to be our natural defence when faced with mortality; some might recall the old Bob Monkhouse pull back and reveal gag which went something like, “I want to die like my dad, peacefully in his sleep… not screaming like his passengers.” But dying behind the wheel isn’t much of a laughing matter.

The title here is a bit of a misnomer really, since it doesn’t really matter where one’s terminal velocity is achieved if it curtails your life. All of which makes Volvo’s mission to eliminate all fatalities in their cars by 2020 a highly creditable one. But every manufacturers takes passenger safety seriously now and certainly, today’s cars are a good deal more survivable than those built even twenty years ago, as I hope I never find out.

Audi's procon-ten in principle: Image drive2.ru
Audi’s procon-ten in principle: Image drive2.ru

During the 1970’s Audi engineer Elmar Vollmer began delving into accident data and what he and other experts discovered was that following the more widespread adoption of front seat belts, the nature of driver injuries altered. Instead of being chest pads for an unbelted driver, steering wheels had become dangerous projectiles, leaving disfiguring injuries as the belted driver’s face and encroaching wheel collided. He began experimenting on a simple mechanical system which would achieve the twin virtues of pulling the wheel away from the driver while keeping her firmly in her seat. The issues for Audi were perhaps greater than others, their nose-biased in-line engine mounting creating additional difficulties for engineers in their efforts to ameliorate encroaching masses.

Vollmer and project leader Helmut Adam created a system using three stainless steel cables and a pulley system fitted to the front of the car. Making use of the longitudinal engine location, these cables were attached to steering column, gearbox, engine firewall and to both front seatbelt reels. As the front of the car’s structure deformed in an accident, forcing the engine back, loads were applied to the cables, pulling the steering column back towards the engine bay while drums inside the seatbelt reels wound them two turns against natural belt stretch.

procon-ten schematic. Image: autoweek.nl
procon-ten schematic. Image: autoweek.nl

This beautifully simple solution, dubbed Programmed Contraction/Tension or procon-ten for short was the first passive safety aid of its kind in the world and was introduced in 1987 as an option across the Audi range. In the US market, it was fitted as standard.

Audi were lauded for this development and Vollmer received an NHTSA safety award for his pioneering work on the system in 1989. Audi fitted the procon- ten system to its cars until 1994 when it got in step with the wider industry by adopting airbags.

It’s obvious there was a convincing argument for getting the steering wheel out of the driver’s path but the limitations of procon were exposed in side and offside impacts, where airbags performed better. Cost, weight and complexity must have played a part in its demise – after all no other manufacturer adopted the system.

The advent of deformable structures, safety cages, airbags, improved material technology and a far deeper understanding of what happens to the human body under rapid decelerations has over past decades led to a huge number of lives saved. However, airbags have proven something of a double edged sword, as anyone who has been affected by a malfunctioning Takata example would attest, had they survived to tell the tale. There’s something almost wilfully counter-intuitive about exploding a device in front of the occupant’s face as a means of saving his life. But perhaps, that’s just me.

Nevertheless, given the amount of passive safety equipment fitted to all cars now, survivability is vastly improved, but weight and complexity continues to grow. Future (engine-less) cars will require different solutions and we’re assured fully autonomous cars won’t crash at all, meanwhile none of us wants to arrive at the scene of the accident. But should the worst happen, couldn’t a simple, elegant mechanical system such as this offer a less complex, surer method of saving lives? (especially for cheaper cars) It would appear that Audi continues to hold the trademark for procon-ten. I’d like to see them use it.

Image: MGS Tech Innovation Technologies
Image: MGS Tech Innovation Technologies

Author: Eóin Doyle

Founding Editor. Content Provider.

7 thoughts on “Theme: Places – Scene of the Accident”

  1. Apparently the issue with Procon-Ten was that the nature of its operation tended to write the car off, even if the damage from the accident itself was otherwise repairable, since the steering column being pulled through the firewall tended to make a non-trivial mess of things. Airbags have their own problems (and have certainly been known to write off a car) but Audi was backing a losing horse on this one and knew it, I suspect.

    1. Yes, this was an issue. And, of course, the supply chain had adopted the alternative airbag technology wholesale, so Audi really was swimming against the tide. Nowadays, replacing deployed airbags adds to the repair cost, but is a relatively tidy operation.

  2. The fact the ProCon Ten system destroyed the car ought to have been a sales opportunity. I expect the insurance companies did not not like it very much which drove Audi customers elsewhere. That hypothesis would be shown to be false if there were no price differences in insuring similar cars.

  3. Procon-ten was simple and elegant system but I think that airbag (or better SRS) could be beter – it holds ones body at greatr area than belts alone thus reducing risk of internal injuries.

    1. I think timing was Audi’s problem more than anything else. They clearly needed to ensure the system was thoroughly tested and had jumped all legislative hoops – (particularly in the US) – before offering it to the public, which delayed its introduction. The insurance industry would not have approved of a system that essentially made cars uneconomic to repair, and probably probably saw premiums for such cars skyrocket. Meanwhile, airbag technology had improved – albeit, as we have seen lately, it still has some way to go.

      Airbags have saved lives, no question and elsewhere in the vehicle I am wholehearted in my approval for their adoption. However, exploding a device in the face of a driver, so that they do not make violent contact with the steering wheel still alarms me. Surely better by far to get the wheel out of harms way. Mind you, why we still need these directional tillers is anyone’s guess…

      Thanks for stopping by NDV.

  4. Eoin: I didn´t know you were an airbag sceptic. On the other side of the coin, there is the risk of risk homeostasis. More airbags makes driver´s more willing to take risks, compensating for the decrease in risk created by the SRS. One wag said the best way to make drivers conduct their cars more safely would be to attach a big spike to the steering wheel.

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