Serious one - Stopping distances

[Lutz]

Your experience confirms the unexpected that Brian was referring to in his response. A car with ABS towing a caravan with good brakes can actually stop quicker than a car solo.

 

[CaptainKangaroo]

I have had the experience of an emergency stop in a car with ABS and a 1500kg van on the back. what I will say it you will not expect what happens.

firts the car feels like it is not braking at all, so you force the brake and the ABS starts, then you hit a brick wall as the caravan loads the rear and applies its brakes. we went from about 40 mph to zero in a VERY short distance. both my brother and I had seat belt marks from the force.

Then instantly you panic that nothing is behind you as you realise the stopping distance you used was too short for anyone a bit close.

This was on a warm dry day, and was caused when a child ran out of a concealed driveway straight into the main road. the parents have now cut down the hedge to make sure people can see into the drive. they also made us a nice cuppa while I checked the van and car for any damage.

steve, keep quite about this one or the council will put a camera and speed humps in place!

 

[Tina3]

Crikey you must,ve been well shook up,bring back "charlie says" Thats how I learnt all my safety stuff when I was a kid!!!! Ha!

 

[BrianStAlbans]

Thanks guys,for a moment there I thought I'd lost it!

 

[BrianStAlbans]

Tina, Brian says...keep off the charlie!

 

[Lutz]

I just read a report that under normal traffic conditions, the average driver achieves considerably poorer emergency braking distances than what cars are actually capable of under 'laboratory' conditions. This even applies to cars fitted with ABS. The reason for this result is that even if the driver is faced with an emergency situation and reacts accordingly with the necessary urgency, he (or she) still does not apply the brakes as forcefully as may be required to avoid an accident. There appears to be a mental blockage built into most people's brain to bang the brake pedal down really hard, even in an emergency. Together with Continental and Lucas, Mercedes Benz is developing a new feature, a so-called brake assistant or BAS, that senses the speed at which the brake pedal is depressed, independent of the pedal pressure. As soon as the electronics sense that the brake pedal was depressed abnormally quickly, as in the case of an emergency, the box of tricks takes over from the driver and applies additional pedal pressure to achieve an optimum stopping distance.

 

[BrianStAlbans]

Lutz,brake assist has been available for some time now on Fords and I believe other manufacturers also.Yesterday I attended a training/track day with Ford (part of my job)part of which envolved an abs braking demonstation .We had to drive flat out in 2nd gear towards a (very brave/stupid) man opperating a light box which when actived determinded if you went left,right or straight on.His main instrution was to hit the peddle agressively and try to push it through the floor.Its only when you have done this do you realize how good abs really is.On another subject I have now been in a Ford Galaxy around a race track driven by a pro driver and ,I swear sharp right hand bend at 90 mph and a hairpin at 70mph,I will never make a bad comment about people carriers again.

 

[Tina3]

is isnt'nt it Brian!! but dont you have a wobbly leg afterwards!!!!!!!!!!!!!

 

[Lutz]

What you appear to describing is ESC or electronic stability control which ensures that the vehicle's handling doesn't go out of control when you attempt an emergency stop at the same time as taking evasive action by steering. I agree, that has been on the market for quite some time.

That's something different to Brake Assist, though. Brake Assist performs an emergency stop even if you only hit the pedal lightly.

 

[BrianStAlbans]

Lutz,I have been a Ford salesman for 10 years so I do know the difference between ESC and brake assist which has been available for several years now.

 

[CaptainKangaroo]

my motor (not ford) has emergency brake assist and is now 2&1/2 yrs old so must have been our for at least that long

 

[Lutz]

OK, my apologies to you both. I got my facts wrong.

 

[Lutz]

The report, which was not dated, must have been a lot older than I thought.

 

[Lutz]

Just re-read the article about the advanced braking system and learned (what I overlooked the first time, hence the confusion) that the main improvement over existing brake assist systems was that it not only provides optimum braking performance in a straight line but also if the trailer (or caravan) is snaking. The brakes are applied alternatively to the left and right hand front wheel depending on whether the car is being pushed to the right or left by a snaking trailer, thus straightening the car up again. Appararently this system is being implemented for the first time on the new Merc M Series. Anybody know any more about it?

 

[Lutz]

Another article landed on my desk today which answers my question about the new Mercedes Brake Assist System. It was a comparison of a new Mercedes M-Series with the new advanced system and a VW Touareg fitted with conventional ESP. Both were towing the same trailer of 1970kg. The conclusion was that the VW was no worse in its ability to catch a snake but the Merc did it more smoothly despite its weight disadvantage (its test weight was 2520kg against the Touareg's 2929kg). The only negative comment on the VW was that it applied the brakes more heavily when a snake occurred than the Merc and this could distract drivers of following traffic, thus possibly increasing the risk of a rear end collision.