Safe Speed Forums

Anyone watch it? A few things I noticed of interest from a safety perspective, mostly centering around the cars they bough for less than £100.

Firstly, the brake test - they all stopped well within the highway code's reccommended distance, even though none of the drivers seemed to have heard of cadence braking. You'd think that on a program like Top Gear they'd at least make an effort to stop in the shortest distance and under control, but no, they just stamped on the brakes. Hence the 1.5 ton Volvo with ABS comprehensively won the test - stopped in just over half of the highway code's distance! Maybe it's time the HC was updated to more accurately reflect the state of the brakes on the majority of cars out there today.

Next up came the crash test - they drove two 'old bangers' into a brick wall at 30mph, and emerged unscathed. JC drove into the wall at 40mph, because his speedo was apparently broken (making his car unroadworthy, but never mind!), and supposedly suffered a broken thumb. Still, I hope this test was representative of the strength of the average car. You could definitely see where crumple zones had directed the brunt of the impact away from the driver. My only concern with the accuracy of the test was that the wall fell over - evidently not all the KE of the cars was transferred back into them - however, this is probably quite representative of a typical crash, as you will doubtless deform whatever you hit.

And finally, how amazing were the 'track day' versions of the 911 and the 360? Their road-holding, even just from watching on TV, was quite staggering.

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-mike[F]
Caught in the rush of the crowd, lost in a wall of sound..

I didn't see it, but I saw last weeks when JC was leaning against a petrol pump on his journey to the south of France(Nice job if you can get it), using a mobile phone, albeit as a calculator.

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Semper in excreta, nur quantitat variat.

Y'know the whole thing about mobile phones triggering explosions at petrol stations is a myth, apparently?

Edit: URL: http://www.snopes.com/autos/hazards/gasvapor.asp
Edit 2: URL 2: http://www.snopes.com/autos/hazards/static.asp

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-mike[F]
Caught in the rush of the crowd, lost in a wall of sound..

Of course it's a myth. If mobile phones could ignite petrol fumes then you certainly wouldn't be able to run your engine on a garage forecourt.
Petrol fumes are highly explosive - in the right concentration, which is about 1:15. Concentrations less than about 1:20 or greater than about 1:10 are very difficult, if not impossible, to ignite. Ever tried to start a flooded engine?
I once saw a fireman who, as a demonstration, chucked a burning cigarette into a bowl of petrol. The cigarette went out.
Don't try this at home!

Absolutely. I used to think it was because it's easy for learners to work it out in their heads. Thinking distance is ten feet per 10mph of speed, and braking distance is increasing multiples of speed (1 x 20mph, 1.5x 30mph, 2 x 40mph and so on). Not so easy to do the mental arithmetic since they went metric on us, so I've no idea why they're still hanging onto it.

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Make everything as simple as possible, but not simpler - Einstein

Of course it's a myth. There is a bigger dangers from the lights in the pumps!!!

The real reason petrolco's are worried about the use of radio transmitters in their forecourts is that it was once discovered that high-powered transmitters used in the vicinity of a petrol pump could confuse the electronics into suspending the counters incrementing while the petrol kept on pumping, so some taxi drivers and users of CB radios were getting free fuel!!

Who would ever have thought that anyone would stoop so low as to peddle a myth about safety considerations just to protect a fiscal interest??

Actually that provoked quite a good argument in favour of ABS, in my mind.

Let's assume that a normal driver wouldn't behave like a numpty, and would actually try not to screech to a halt with all 4 wheels locked. In an old car with worn out and probably unbalanced brakes it is quite likely he would be on and off the brakes all over the place as some wheels lock and others don't etc. I've driven cars like this on occasion, and it certainly makes you realise the importance of keeping everything properly sorted.

But working ABS could be a Godsend in this very situation. If (say) one wheel is locking way early due to a warped or distorted disc / drum, then ABS will do a great job of keeping that wheel turning whilst still allowing the other 3 to work up to their limit. This is something that the best cadence braker in the world cannot achieve - he has to moderate his braking according to the wheel that locks first, and if this is a dodgy rear drum the front discs may never work at more than a fraction of their capability as he struggles to maintain control. Indeed the best thing may indeed be to abandon the attempt and simply to lock the whole lot up and hope for the best!

So in reality, maybe the biggest benefits from ABS are yet to be revealed to us, as they rescue older cars by allowing them to get the best out of their improperly maintained brakes.

Is this another illustration of how today's engineering improves safety years down the track?

I used to work as an electrician in the pharmaceutical industry, and am familiar with all the ins and outs of working with electrics in hazardous atmospheres.

Only the inside of the pump casing itself is actually designated as a hazardous "zone 1" area, if it were otherwise then it would be illegal to start and run a car engine. Mobile phones don't even register on the radar as a comparitive risk, their operating voltages and level of containment are such that they would all but be certified as "intrinsically safe" in any case.

I suspect the bans on smoking, phones etc are more a matter of putting the public at ease than anything else. In fact, an ex-colleague used to illustrate this point by brazenly smoking whilst filling his car up at the local garage, to the alarm of the staff and all around him! Technically he was in the right of it, but then it has to be said that tact was never his strong point!

Yep, and I'm familiar with the ring of fire that passes for a commutator/brush system in a ten year old ill maintained starter motor - as fitted to every third car on any petrol station forecourt and as operated on every single visit!

I'd hazard a guess that the ignition potential of the starter motor is at least 10,000 times greater than that associated with a cell phone.

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Paul Smith
Our scrap speed cameras petition got over 28,000 sigs
The Safe Speed campaign demands a return to intelligent road safety

Ah, I see. Didn't occur to me that ABS could apply different braking efforts to each wheel. That would certainly explain why it's such an advantage.



Aren't speed cameras "today's technology"? *Shudder*

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-mike[F]
Caught in the rush of the crowd, lost in a wall of sound..

Yes, the general principle is that wheel sensors detect when a particular wheel is slowing down too much and ease the brake back off that wheel, without affecting the others.


Please note that I said "engineering", not "technology"!

I can't read!

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-mike[F]
Caught in the rush of the crowd, lost in a wall of sound..

Before I retired from tanker driving, we had an ABS course at RAF Scampton using an artic at 44 tones. The rig was switchable from ABS to non-ABS. We proved that, in the dry, non-ABS with locked wheels, stops quicker than with the ABS.
Apparently they proved this on all the courses they ran (and probably still do). Mind you, on a wet polythene sheet the results were startlingly different! Quite an eye-opener of a course.

Surely it's not just about stopping in the shortest distance possible. Being able to steer at the same time is equally as important in my mind.