Oh my god.

[Llanigraham]

Re fire:

Research has taken place over this, in the last few years, and I'm sure it was found that it is not intially the cars fuel that causes the fires but the brake and clutch fluid that ignites as the reservoirs are torn from their mountings and the fluid is sprayed onto hot exhaust maniflods and turbos.

[gadgetman]

Glad to hear the police confirm no more trapped bodies on the M5, so 7 is the maximum fatalities. I feared it was going to be so much worse.

+1

It's amazing, yet still saddening, that the number who died wasn't much higher.

And the highways agency are looking at removing motorway lighting!

[Paul007]

It happened again on the M6 last night. This business about removing motorway lighting is stupid. The motorways local to me still have the columns but they're switched off - to save money - but what about lives...

http://www.bbc.co.uk/news/uk-england-lancashire-15610558

[GentleGiant]

+1 for brake fluid being the main cause of fires after car crashes, diesel doesnt burn easily, petrol needs a spark or naked flame, but brake fluid just needs a hot manifold.

[Evening Star]

Well reading that I learnt something new today.

So why not make brake cylinders out of two parts, an outer metal case for strength and an inner liner for the fluid or is that too simple?

[nick74]

Re fire:

Research has taken place over this, in the last few years, and I'm sure it was found that it is not intially the cars fuel that causes the fires but the brake and clutch fluid that ignites as the reservoirs are torn from their mountings and the fluid is sprayed onto hot exhaust maniflods and turbos.

That's interesting, I seem to recall reading the same thing. Ironically, ABS systems tend to have a far more complex pipework containing brake fluid running around the engine bay than a traditional braking system, which probably doesn't help the situation either.

[Kernowscoot]

I was lucky enough to miss this crash by about half an hour, on the way back from Bristol, down home, I can promise you the fireworks would have made no impact as the fog was unbelievable at some points, really poor visibility, my phone went mental from people ringing me up as they knew I was on the m5! I feel pretty lucky to say the least, if I'm being butaly honest most people were driving pretty safe, but it would of only taken one, and trust me there wouldn't been much I could of done if somthing just stopped in front of me, the fog was savage.

I was a bit behind you........and got caught in the traffic at 8.30. If it hadn't have been for a fuel stop I would have been in it.

I was safe enough but close enough to see and smell to much (was by the 1/2 mile sign for jn 25)

We finally got turned around and off the motorway at 3am.

[Chris Coates]

Well reading that I learnt something new today.

So why not make brake cylinders out of two parts, an outer metal case for strength and an inner liner for the fluid or is that too simple?

Simplicity is one thing - cost is another.

Most companies will take the minimum cost possible - usually by lowest bidders at tender...

Unless there was some sort of standard to force companies to do it, chances are they wouldn't.

[gadgetman]

Given how close the scene is to the junction, could it be someone came ploughing up to join and met bunched up traffic causing this in their wake?

[grr666]

I was on the M5 that evening but nearer to Bristol.

Got to say the fog was bad in places but still quite patchy.

Me, Mrs Grr to be and her Mum were attending a family party.

We set off in the SDI at about half past eight and were heading home

at about midnight. On the way back on the M5 we saw a few Police vehicles

heading off somewhere in a darned big hurry. We had no idea

about the crash until the morning. We dropped the mother in law and the SDI

off and went on home in the Mazda (were using it the next day) on

the last leg of the journey in the MX5 the fog had worsened considerably.

So sad to hear about something like this so near to Xmas.

[The Ors]

Simplicity is one thing - cost is another.

Most companies will take the minimum cost possible - usually by lowest bidders at tender...

Unless there was some sort of standard to force companies to do it, chances are they wouldn't.

I agree about forcing better safety standards but I think the blame lies with Joe Public rather than the car companies.

Most people want to pay the minimum possible for any manufactured goods. If they pay more it will be for something tangible like aircon or leather seats rather than something intangible like 'improved safety'.

According to US insurance figures SAAB make the safest cars. Or rather they used to; they went belly up because no-one was buying them!

Some of the M5 witness quotes make for sobering reading. :(

[GentleGiant]

It isnt the pipe and pumps that break and spray fluid, it is the plastic reservoir that snaps off from the G forces and pours 1/4 - 1/2 litre of fluid onto the manifold; that is why you often see the reservoir strapped into place with nylon "tywraps" on amateur rally cars.

Back in the pre Clackson owned era, Top gear did a study and filmed a demonstration of what happens after a crash.

Newer cars, with brakes, steering, clutch and suspension all using highly flammable fluid filled reservoirs placed inside the crumple zone and right next to an extremely hot manifold are very badly flawed designs; especially as there are NON FLAMMABLE fluids out there, that that could be used if they bothered to spend the money to modify the systems for the slight differences in operational efficiency.

[cheezemonkhai]

What with regenerative braking, maybe it's time to move to regenerative/resistive brakes.

So apply a current to the brakes and they show you down. After all it's just an inductor in one way, so could be run backwards to stop the movement.

Gets rid of the brake fluid, although it would mean that the cost might be higher.

[Evening Star]

What with regenerative braking, maybe it's time to move to regenerative/resistive brakes.

So apply a current to the brakes and they show you down. After all it's just an inductor in one way, so could be run backwards to stop the movement.

Gets rid of the brake fluid, although it would mean that the cost might be higher.

Well unless you know a way of hiding the resistance grids which you'd use to dissipate the heat & protecting them from saline solution then be my guest.

[GentleGiant]

Regenerative brakes arent that effective; what do you do in the unlikely event your battery is fully charged, and what about the hand brake???

Edited 8 November, 2011 by GentleGiant

[cheezemonkhai]

Capacitor on the brakes (for emergency reservoir of power), and when you need to brake, an electrical current is sent into a coil in what would be the current caliper.

This induces a magnetic field, that would pull strongly on the iron/steel brake disks and retarding them.

Just the same as a normal brake works, only you're using magnetic resistance to retard the vehicle over friction.

So you'd need to get a heat sink on the back of the electrical coils, but you're still going to be getting rid of the same amount of energy for a given deceleration as you would using normal brakes.

Edited 8 November, 2011 by cheezemonkhai

[GentleGiant]

I dont have a degree in math or physics, but I do know that to make a magnetic field large enough to stop a car in a reasonable distance would require either so much machinery to at least triple the weight of the car, or be made of such exotic magnetic material (which is in short supply since China has temporarily suspended exports of most of it), that you couldnt build a car for less than £100,000, and would STILL be 50% bigger and heavier.

[Kernowscoot]

Alternative braking systems do exist, albeit on larger vehicles. Coaches have had a system called "Telma" for years.

TELMA

There are also exhaust brakes as used on lorries, I'm sure that could be adapted to diesel cars.

[andyspan]

Alternative braking systems do exist, albeit on larger vehicles. Coaches have had a system called "Telma" for years.

TELMA

There are also exhaust brakes as used on lorries, I'm sure that could be adapted to diesel cars.

I think these devices are only retarders and do exactly that, ie they don't bring the vehicle to a standstill they are just used when travelling downhill to hold it back and lessen the use of the braking system.

[cheezemonkhai]

That sounds pretty much as I just described:

http://en.wikipedia.org/wiki/Telma_retarder

Of course a simple option would just to be to adapt current systems to use silicon DOT5 brake fluid.

[nick74]

It isnt the pipe and pumps that break and spray fluid, it is the plastic reservoir that snaps off from the G forces and pours 1/4 - 1/2 litre of fluid onto the manifold; that is why you often see the reservoir strapped into place with nylon "tywraps" on amateur rally cars.

Back in the pre Clackson owned era, Top gear did a study and filmed a demonstration of what happens after a crash.

Newer cars, with brakes, steering, clutch and suspension all using highly flammable fluid filled reservoirs placed inside the crumple zone and right next to an extremely hot manifold are very badly flawed designs; especially as there are NON FLAMMABLE fluids out there, that that could be used if they bothered to spend the money to modify the systems for the slight differences in operational efficiency.

Looks like this was it;

Incidently according to the tax disc website 'D54 BAD' survived another 11 years after its ordeal on that program.

[GentleGiant]

Sadly the GFWoC stops me from accessing youtube, but I am guessing you have the right vid clip; I am glad to know my memory hasnt totally gone after the massive steroid treatments I had a couple of years ago.

@Cheezemonkhai,

Thanks for that, I KNEW I had retro-fitted a hydraulic system with a non flammable fluid, but I couldnt remember what it was.

I CAN still remember the amazement in finding out the 1,500 Celsius furnace at my then employers was using standard DOT4 to operate the rams and furnace doors. The idiots even put a 20 gallon reservoir tank UNDERNEATH the furnace; guess what happened when a hydraulic pipe burst???