Gravel Traps

[NICKR]

Do you think that gravel traps are the best method of stopping a car when it leaves the circuit.

My feelings about them are mixed. Yes at certain speeds they do their job but at high speeds, in the wet and when a car enters them sideways their performance is suspect.

What do you think ?

What alternatives are there ?

[Paul V]

As far as i can see the best form of arrestor is good old tarmac, one of the things a racing car is (hopefully) good at is sticking to tarmac.

A possible solution would be to have a strip of grass at the edge of the track, and the rest up to the armco to be tarmac (coloured green if they want).

Have some of the superspeedways done this already?

[AndyF]

Gravel traps seem to work some of the time, but usually they are either too deep (cause the car to roll if going sideways) or not deep enough so that cars can just drive out of them. I am not sure about replacing them with tarmac or grass, as you would have to extend the run-off areas a great deal.

[Marshal]

Not gravel, damages cars and makes Marshalling very difficult (have you tried running through gravel with a fire extinguisher? -or moving a car through a gravel trap out of a dangerous position). I'd be in favour of a strip of grass with high grip tarmac behind it.

Andy, why would a tarmac run off area need to be larger?

[Dan Friel]

Marshalling with gravel is always a pain, surely there's a better alternative these days.. even for somewhere like Paddock at Brands??

[AndyF]

I dunno....at high speed corners (180mph F1), surely tarmac will not have the same stopping effect as gravel??!!

[Lola]

It's better to hit gravel if your brakes fail!!!!

[Dom]

I think replace gravel with tarmac and armco with big n bouncy airbags. I believe they also use water bags in the US to stop monster trucks.

[AndyF]

I think it depends on the corner that you are talking about. For example, I don't think that you could put tarmac at Paddock Hill Bend, as cars would just run over it to go faster. Likewise, I think the gravel does an excellent job at Druids bend at Brands too -I don't think that tarmac would stop the cars hitting the barriers. Also with Druids, cars very rarely go into the gravel at such a speed or angle that they roll.
Many corners use grass, and although they don't have as much grip as Tarmac (especially in the wet) are useful at large circuits like Thruxton.

[DNQ]

Originally posted by Dom
I think replace gravel with tarmac and armco with big n bouncy airbags. I believe they also use water bags in the US to stop monster trucks.

I think they already use water-airbags on the exit of the tunnel at Monaco. Remember Alex Wurz's crash in 1998?

[XAutoRacer]

The safety aspects of most race circuits are not optimal....
obviously, gravel traps slow cars fairly safely if they are not too sideways....highway design features should give some great ideas about what doesn't work, as should Indy and the NASCAR tracks....Charlotte Motor Speedway is experimenting with encapsulated energy absorbing foam....I think that's an excellent idea, but potentially only a one shot....race cars and drivers can take a hell of a beating without permanent consequences....
several ideas come to mind....US buses have water filled bumpers that absorb some halacious energy levels...then just fill them back up with water....that suggests a water filled wall with orifices that permit the water to be exhausted into a reservoir, then quickly re-filled after a collision....of course, some drivers just don't get off the track that often, and seem to win most of the races....maybe more skillful drivers need to be recruited....

[RickP:Clio51]

While racing at Spa this year, I had a tyre deflate on the run into Blanchimont (at around 150mpg in the Clio V6).
As I turned in, the car swapped ends and I went across the new tarmac, where the gravel was until this year, and into the wall.
Undoubtedly, I scrubbed off a lot of speed before hitting the wall spinning on tarmac, and I didn't have the risk of rolling over (which probably wasn't that likely at the angle I went off at) but I doubt I would have been stopped by gravel at the speed I was travelling.
It certainly lessened the ferocity of the corner which used to be terrifying and stopped several major accidents during the weekend.
I am still unconvinced, but watch the Belgian GP and form your own opinions as they are the first to have replaced large areas or gravel with tarmac.
Cheers
RickP

[XAutoRacer]

Originally posted by RickP:Clio51

Undoubtedly, I scrubbed off a lot of speed before hitting the wall spinning on tarmac, and I didn't have the risk of rolling over (which probably wasn't that likely at the angle I went off at) but I doubt I would have been stopped by gravel at the speed I was travelling.

Here in California, we have gravel traps to stop runaway trucks. The traps seem to work due to the loose nature of the gravel, and the deep penetration of the heavily laden and relatively narrow tires into the gravel. I don't think that the parameters that make gravel traps work for trucks are necessarily operative with race cars. Even on so-called "showroom stock" cars these days, the tires are very wide and lightly loaded.
MIRA (the test track in England) has a parabolic banking which permits very high cornering speeds with relative safety....I wonder if this principle could be applied to auto racing....with a significant penalty for exceeding the confines of the marked race surface....

[AndyF]

Surely this would just make the racing confusing - you wouldn't know the winner until hours after the event!

[XAutoRacer]

OK...how about the old airport circuit rule....you have to return to the track where you left it....that way you couldn't use the banking as part of the track....

[elephino]

Part of the problem with F1 cars is their flat bottom. They basically skip over the gravel instead of dig into it and stop. Gravel traps work best with heavier vehicles where something can bite into the gravel. Admittedly it can and does cause rollovers but that can be better than hitting a wall at times.

[XAutoRacer]

elphino's point is well taken....NASCAR vehicles have an air flap on the roof to increase aerodynamic drag and reduce the number of rollovers....how about a mandatory gravel digger that is tripped when you leave the racing surface and automatically retracts when you return....similar technology to the wire cables that arrest aircraft on carriers...

[elephino]

Only problem with that is that the car is then stuck in the gravel.

NASCARs flaps, which are "activated" when travelling backwards are there to stop the car flipping up by reducing lift, rather than creating drag.

[XAutoRacer]

Originally posted by elephino
Only problem with that is that the car is then stuck in the gravel.

NASCARs flaps, which are "activated" when travelling backwards are there to stop the car flipping up by reducing lift, rather than creating drag.

There could be a manual as well as automatic device to raise the gravel digger.....

Another incredibly stupid idea to get things going, again....how about a high strength steel cable (but with high ductility, i.e. some stainless steels) that is on a vehicle mounted reel attached to a ductile torsion bar shaft....when the car leaves the track at very high speed, an anchor is shot into the asphalt....the cable/reel then bring the car to a rapid halt before it hits any barriers....once the car stops, the reel/anchor are jettisoned....even the most inept driver should only need two.....

[Lola]

The drivers head would fall off.

Popeye wins a grand prix

[XAutoRacer]

Originally posted by Lola

The drivers head would fall off.

Popeye wins a grand prix

This Lola must race tricycles, or some other toy....only an idiot like Barry Myers (see his report on Dale Earnhart) would even contemplate an injury related to head inertial forces....the car isn't strong enough....the poor folks who are racing in Formula One get head injuries (ie concussion) from driving across the gravel trap unimpeded, penetrating the tire wall and banging into the guardrail that the tirewall is intended to stop the car from contacting...sound familiar???....just happened last weekend....

[elephino]

Well, not quite. Burti really only caught the edge of the gravel trap. Yes he went through it, but a very short trip through it and then head on into the tyres and wall, not at an angle, which is when the tyre barriers work best.

[XAutoRacer]

Originally posted by elephino
Well, not quite. Burti really only caught the edge of the gravel trap. Yes he went through it, but a very short trip through it and then head on into the tyres and wall, not at an angle, which is when the tyre barriers work best.

I thought that was exactly the point of the discussion, however. Isn't the goal to come up with some "brainstorms", be they hit or miss, in the hope that one might spark a practical idea? Most of the good ideas in racing (like tire walls) have dramatically increased safety.....but the Burti incident points out that the devices are not omnidirectional, while racing wrecks often are...

Rather than be a complete naysayer like Lola, it would be better to establish a design criteria that the shear forces on the driver's neck generated by the stopping device not exceed a reasonable injury threshold. This force level could be quite high....approaching the deceleration rate of an F-1 car when it hits an immovable barrier....say 30-60G on the platform of the car....

[Lola]

anchor

Im sure the circuit owners would love to see anchors tearing up their tarmac. These are racing cars not cruise liners.
Move over TGF sinbads on pole.

[XAutoRacer]

Originally posted by Lola


Im sure the circuit owners would love to see anchors tearing up their tarmac. These are racing cars not cruise liners.

Excellent point....then how about cables that spring up out of the gravel and catch swivel hooks that extend down from the underside of the car when there's a sudden change in acceleration....although I still kind of like the idea of a scoop that increases the decel rate if a car goes straight across the gravel like Burti....

It still seems like better drivers are the ultimate answer....just keep the stupid car on the black part....it's not only safer, it's usually faster than taking a trip off-course. (the exception being the Richard Petty line through the esses at Riverside)