Electronic handbrake design fault

[cunninghamj4]

Last week I was involved in an RTC while driving my car.

I was traveling on a motorway with a speed of around 60mph.

It had been raining that day and I was wearing a large rain jacket. I was driving and so I was in the driver's seat.

While attempting to change lane I had to do a shoulder check and twisted

 

[cunninghamj4]

Whoops, posted too early ....

I twisted myself around and on doing so, my jacket got caught under the handbrake button and pulled the handbrake on causing an immediate stop in the live lane of the motorway. The result of that was that the driver behind me drove straight into the rear of our car.

Surely it's not right that it could be so easily accidentally applied??

On reflection, I feel like if the car is travelling above a certain speed and a handbrake is applied, it shouldn't be able to function and a dashboard warning shown instead?

I can't be the only person this has happened to, and it was only by shear luck that the driver behind was able to do an emergency stop causing cosmetic damage only to the boot and bumper of our car, and her front bumper.

I'll be getting in touch with seat about the location of the button, but curious to know others opinions on its location. I think it would be better placed on the dash.

 

[cunninghamj4]

 

[BigJase88]

It's a safety design feature. If say the driver has a funny turn the passenger can apply the brakes. I think it actually applies all 4 brakes and not just the rear ones

 

[H Rafiq]

Hope you’re okay. If you had a manual handbrake lever, this would have been avoided.

 

[RADIOTWO]

It's a safety design feature. If say the driver has a funny turn the passenger can apply the brakes. I think it actually applies all 4 brakes and not just the rear ones

The hand brake only works on the rear wheels, but when the Hill hold works that applies all brakes

 

[Glosphil]

I have heard of a driver's (or was it a passenger's?) clothing applying a manual handbrake.

As in 3-1/2 years I have never touched the handbrake switch so if it's location was on the centre of the dash (as the OP suggests) it would make no difference to me.

EHB only apies rear brakes I thought & AutoHold applies all 4.

 

[BigJase88]

The hand brake only works on the rear wheels, but when the Hill hold works that applies all brakes

Yeah but on the move in an emergency situation i believe it applies all wheels as locking the rear wheels would be dangerous.

In normal use yes it just applies rears

There was a video out years ago of maybe even Jeremy Clarkson trying it at speed. Trying to find it

 

[RUM4MO]

So, who is going to be brave/stupid enough to test the "all wheels" or "just rear wheels" theory?

Logically, operating the handbrake switch should only send a signal to the handbrake controller which will drive out the motors on each rear wheel - but as most controller talk to a common "brain" maybe VW Group has set this up so that a handbrake demand at higher than yMPH, does indeed use the ABS valve block and pump to initially apply the brakes to all wheels.

I think, if you only flick the handbrake switch ON while the car is moving at a reasonable road speed, that command will get ignored, but as said earlier, if you hold it ON it will get operated and so give you some protection against a throttle module/ECU failure, as does the brake pedal switch. Also, I have always considered that the design of the electric handbrake switch is deliberate to minimise this sort of "clothing issue" to occur, just bad luck, very bad luck, I thought that there were now some motoring directives/strong suggestions, that driving while wearing unsuitable "apparel" was, in the event of an accident, an offence.

I certainly don't mess about with having restrictive etc clothing on while driving, that gets removed and dumped in the boot before I jump into the driving seat - just common sense to me, that is all. I do know many people that don't operate that way, which is okay until something like this happens.

 

[martin j.]

Why I never wear a jacket in the car, apart from comfort, I remember on a club run someone lifted a camera in the car in front and the strap caught the handbrake lever, sudden stop, that’s why I leave a gap!

 

[RADIOTWO]

Yeah but on the move in an emergency situation i believe it applies all wheels as locking the rear wheels would be dangerous.

In normal use yes it just applies rears

There was a video out years ago of maybe even Jeremy Clarkson trying it at speed. Trying to find it

How can it operate on all four when there is only two wheels with parking brakes

 

[BigJase88]

How can it operate on all four when there is only two wheels with parking brakes

Computer wizzardy.

All electronic controlled. The ABS is ECU controlled so it's not too hard to imagine that switch could engage all 4 brakes

Maybe someone with the correct technical knowledge can confirm this but i 100% watched a video of a golf mk7 and the test was engaging the electronic handbrake at speed and it came to a controlled stop.

It was either carwow or topgear when electronic handbrakes were in their infancy. It was most likely top gear.

Stopping with the rear brakes only in an emergency situation would be dangerous and i doubt it would come to a stop as quickly as what the OP has experienced

Found the video now im still unsure if it applies all brakes or just rear. However he couldn't get the back to step out so maybe applies all

 

[mty12345]

Computer wizzardy.

All electronic controlled. The ABS is ECU controlled so it's not too hard to imagine that switch could engage all 4 brakes

Maybe someone with the correct technical knowledge can confirm this but i 100% watched a video of a golf mk7 and the test was engaging the electronic handbrake at speed and it came to a controlled stop.

It was either carwow or topgear when electronic handbrakes were in their infancy. It was most likely top gear.

Stopping with the rear brakes only in an emergency situation would be dangerous and i doubt it would come to a stop as quickly as what the OP has experienced

Found the video now im still unsure if it applies all brakes or just rear. However he couldn't get the back to step out so maybe applies all

It entirely depends on the way it's coded. I imagine that even if it does only act on the rear wheels initially, then the traction/stability control would also apply front brakes shorty after, in an effort to keep the car pointing in the same direction the steering wheel is requesting it goes.

 

[cunninghamj4]

Tbh, in the midst of panic, when the car began its emergency stop, I had no idea what was happening. I didn't realise the handbrake had been applied and so because I was on a motorway, I may very well have put my foot on the brakes too which I guess might have accelerated the stopping because it was definitely not as smooth as in the video above, the abs kicked in and it felt like the car was fishtailing a bit.

 

[SuperV8]

Tbh, in the midst of panic, when the car began its emergency stop, I had no idea what was happening. I didn't realise the handbrake had been applied and so because I was on a motorway, I may very well have put my foot on the brakes too which I guess might have accelerated the stopping because it was definitely not as smooth as in the video above, the abs kicked in and it felt like the car was fishtailing a bit.

There is mention of the EPB use in an emergency in the Leon manual - unfortunately doesn't mention if it applies to the rear axle or both axles through the TCS.

Emergency braking function
Only use the emergency brake function if you are unable to stop the vehicle with the foot brake ››› . ● Pull and hold the ››› Fig. 191 button in this position to forcefully stop the vehicle. At the same time, an acoustic warning can be heard. ●
To stop the braking process, release the button or press the accelerator.

 

[Glosphil]

As the manual states that "the braking distance may be considerably longer" this does suggest only the rear brakes are used.

 

[Rockbox]

It's a good one for the insurance companies to fight over

 

[cupra14]

Some cars (e.g. Jaguars) behave differently, e.g. above a slowish speed they apply the brakes only partially with the first use of the e-brake, then if you keep using the e-brake they apply the brakes ever harder. I think in the scenario described above that the brakes would have been applied only gently (10% or 5% or such).

 

[cunninghamj4]

It's a good one for the insurance companies to fight over

It would be, but I was reminded that section 197 of the highway code prohibits a driver from wearing lose, bulky or ill fitting clothing while driving which may impact their driving. So even though the driver behind collided with me, I'm at fault.

Lesson learned in the form of excess payment and nearly crapping my pants.

 

[pauly1299]

Last week I was involved in an RTC while driving my car.

I was traveling on a motorway with a speed of around 60mph.

It had been raining that day and I was wearing a large rain jacket. I was driving and so I was in the driver's seat.

While attempting to change lane I had to do a shoulder check and twisted

Why wear a large rain jacket while driving? And I only turn my head to check when changing lanes.