MANUAL

PSM was never turned off and yet it failed each time probably because it is a brake-based stability control. The only time PSM succeeded was when you teamed up your countersteering and throttle inputs with its counterbraking to have a successful shot at stabilizing the initial slide. And this success was achieved through practice. And we are talking about a hard 90 degree turn of the steering wheel at 75 MPH.

According to Mikey, our only self-confessed witness to the accident, the Ferrari was entering the track, startling Ben and he swerved. Do you believe it is possible he swerved with a steering wheel angle of 90 degrees? At 120-140 MPH, driving a car that has sensitive steering, is mid-engined, and is extremely responsive to any inputs, perhaps anywhere from 10 to 45 degrees of steering input may have been required along with not lifting completely off the throttle to safely swerve without upsetting the dynamics. However, the shock of seeing another car appearing suddenly may have caused him to lift off throttle completely, brake and naturally, as most humans would, overreact his input to 90 degrees. Even if the CGT had PSM and Ben teamed up with it, he would have had the requisite initial slide you experienced on the skidpad before stabilization. Except his slide would have started at 120 instead of 75 MPH. And by the time he and PSM stabilized the car, the car would have traveled onto the grass. ABS braking on the grass allowed the car to scrub off approx. 40 MPH before slamming almost perpendicularly into the concrete wall at 80 MPH. Hitting the concrete wall at 80 MPH, not having a 6-point harness nor a head and neck device did the most damage. PSM or not, Bob, you have convinced me he and Corey were unlikely to escape hitting the wall.

An unsavory character like Stefan Eriksson walks away from 162 MPH while Ben and Corey do not from 80 MPH.

According to this article BMW's Bosch-ZF system on the E60 5-Series enables AFS (active front steering) and DSC (dynamic stability control) to work together to produce a reaction time approximately four times faster than a brake-based system like PSM:

Recent demonstration runs at Bosch's Boxberg proving grounds in Germany revealed that spinning out a BMW 5-series with Active Steering is virtually impossible. In response to wildly aggressive steering inputs during abrupt lane-change maneuvers, the car reacts calmly and predictably with no tendency to wriggle its tail. Thanks to the quicker steering ratio available at moderate speeds, the blurred elbows and frantic wrist action usually necessary to negotiate tightly spaced slalom cones are unnecessary. An Active Steering BMW slinks through a serpentine path as if it's hinged in the middle.

I wish the AFS had an "off" switch. I have driven an AFS E60 and did not like it when braking from a 60 MPH straight and turning into an blind, 90 degree unfamiliar corner. The second time I approached the corner, I knew from past experience how to compensate for the AFS ratio change but it still felt both strange and stimulating having to think about and compensate for yet another variable when cornering. Perhaps with more seat time, compensating for AFS becomes second nature.

Mayhap BMW should let you loose on PMG's skidpad with their fully loaded E60 to see if you can defeat the system.

http://www.findarticles.com/p/articl...3/ai_108098152


One of the current performance cons with AFS is the motors will burn out if one likes to play and hold a car in a drift. I wonder if Porsche has this problem with its variable ratio steering:

Now, where else can u spin , slide and throw the car about so much? I was laughing and enjoying myself all the way. My co-driver and i were basically trying as hard as we can to hold the car in a slide. (Met with much discouragment from the instructor. “You’ll burn-out the active steering motors!!” “ease-off, ease-off…”)

http://louiscars.com/2006/03/20/atte...vers-training/

Jason's link:
http://members.rennlist.com/jandreas...fVDC-BOSCH.pdf

Bob Rouleau

Manual - great links. Thanks. I think the case is proven, PSM/ESP can help a great deal but as I theorized, braking one wheel can do only so much. By deliberately (brutally even) tossing the PSM equipped car into a slide, it was unable to compensate enough. Perhaps, active steering would have added enough input to the system to prevent the slide. From the above it sounds like it would. On the other hand AFS isolates the driver even more from the "driving experience". To quote one of my more memorable engineering profs, "everything has side effects".

It is sad that Ben did not hit the barrier straight on, with crush zones and a very rigid tub it might have been surviveable. From what I saw the car hit the barrier sideways - no crush zones there and without a Hans .. the outcome was predictable. Racers know that if you are going to crash, "go straight in". That assumes one has enough control to do so.

Regards,

MANUAL

Wise prof. Bittersweet words. Many thanks, Bob.

Les Quam

Bob ,
I prefer when I realize a crash is unavoidable to bounce or deflect rather than "go right in" as you stated. Any time I can avoid a direct and sudden stop in favor of deflecting the impact or bouncing off as many other objects as possible I will and unfortunately have done the bouncing/deflecting as opposed to a direct immediate stop.

I remember watching the Earnhardt fatal crash and when everyone thought he would be OK I was thinking that was a lot worse than it looked because he went right into the wall without rolling or sliding down the wall. From my experience and observations it's always been the drivers who went right into something with out dissipating the impact where the worst injuries occurred.

Nick,
The CGT as you know revs up blindingly quick I would assume due in part to the small clutch. Like the guy said it is a different animal.

Bob Rouleau

Les, I cannot fault your logic. The operative factor is "if". Sure if I can take a glancing blow which will not cause further harm, I'd go for it. On the other hand, if I felt that the "bounce" might cause me to slam into another obstable sideways, I'll go for the longest straight(ish) I can take with maximum braking. Modern cars can withstand an amazing impact on the nose while still protecting the occupants. Especially a Porsche. The same cannot be said for a hit on the drivers door. There is no crumple zone and the occupant(s) take the full force. I saw a nasty hit at an NER DE once, a 935 lost its brakes at 150MPH headed into a carousel turn. The driver (very experienced) tried to turn in and scrub off speed .. he spun and hit the berm passenger side first. Had he had a passenger it would have been fatal, the roll cage was pushed in as far as the gear shift. He walked away from it because he was lucky enough to have hit the berm with the other side. That, was pure luck. Me? In his shoes I don't know what I would have done, probably the same thing because with no brakes, what else can you do but try and slide the car to reduce speed. Still, the outcome was pure luck.

Let's agree to simply not crash!

pcar964

Every time I read something like that, I feel better about my decision to stop DEs until I have my car prepared. Too much speed, not enough metal

Les Quam

Bob,
I think our different perspective on this issue stems from all of my crashes coming in Kart racing and open wheel competition. I don't think I have hit anything in a full bodied car? (I think I just jinxed myself?) So I never really considered crumple zones before. In Karts and Formula cars the crumple zones are your legs so I learned to deflect and keep bouncing as best I could.

I think you are correct in your analysis using full bodied cars as your example. Can't disagree with your logic as it applies to sedans.

FWIW I think had I been in Ben's position I would have drilled the Ferrari rather than take my chances in the grass or wall. My two cents.

1AS

Hi Jeff,
Les's point is fairly mundane, in that there are a few ingrained "if you're going to crash-do the following" scenarios that most experienced track drivers anticipate. Something like "if you're going to go off-track, point the wheels straight", is an early basic. Another is "don't swerve for small animals-just hit them" since that damage is less than that resulting from a high-speed swerve. This scenario is a variation. The NASCAR big crashes generally aren't from a driver suddenly swerving, but from someone slamming into another driver who is trying to make an adjustment to line or speed. Complete brake failure or other calamity generally results in "try to spin away from the wall". In those scenarios, the experienced driver is always looking at where he wants to go, not at what he's going to hit, until the moment he gives up, and tucks in.

Any time you start going fast, you first are aware of the hard points around the track, and those are the places you tend to give yourself the greatest margin.
The instantaneous decision of "do i just slam on the brakes and run up his rear?", vs "can I just ease down the track and stay in a straight line?" are really the two decisions that could have been made differently, and are the "driver responsibility"issues this thread has discussed. The flip side is "if you can't make that decision, don't go that fast", and that one is more obvious as driver responsibility.

My point has always been that for the driver who is inadequately experienced to react competently in this type of emergency, would computer assist have helped? You can see why Les might not need them, and someone who needs more time to deliberate might. That's not a slam on anybody, just re-re-re-statement that supercars put the driver in a situation where he needs to react more quickly than he has anticipated, and most drivers are inadequate in that circumstance. The speculation in this instance is that any steering adjustment could have been accompanied by only a minimal throttle lift. Slamming on the brakes and swearing at the idiot in front of you would be option A for most.

In a more self-centered mode, I might also point out that when somebody screws up a signal and puts you in jeopardy of crashing, saving his butt at your own risk falls way down the priority list.

Lastly, these instatananeous decisions are why high speed driving requires 100% focus, and why demo runs with passengers aren't a great idea unless you intentionally take some velocity out of your efforts That's one I learned the hard way, and never felt more stupid in my life. (except perhaps for some of my hyperbole here)AS

Bob Rouleau

Alex - Nicely put. An experienced driver has instinctive knowledge of what to do in situation requiring emergency avoidance. I'll add to Alex' statement that the reaction does not require deliberation - it is an unconscious reaction (sometimes called "muscle memory").

Under normal circumstances, nobody who has driven a car for any length of time would swerve at high speed. Note, I said "normal circumstances".

Racers have to deal with obstacles that suddenly appear - parts of a car flying off - in my case, a wheel rolling across the track in front of me as I exited a high speed blind corner. With enough seat time, punctuated with sphincter clenching moments, one learns to react correctly. At high speeds any significant input (brakes, steering etc.) may produce a loss of control. The secret is to react promptly (no time to think - just act) and make a subtle change, or if that won't do, no change at all. Above jeff said that rear ending the ferrari would have been the right thing to do. I think he's right. Two banged up cars, but no fatality.

Best,

MANUAL

Many years ago, I was taught the above applies on the street for man/woman/child jaywalkers as well. Far better to slam on the brakes and hit a softer object than to swerve and hit an oncoming car/SUV/semi-trailer truck endangering your passengers and yourself. I feel queasy thinking about it now but when I sit in the driver's seat, the feeling disappears.

Earlier I thought of Ben as a hero for giving up his life in order to save the Ferrari driver. Alas, I forgot about Corey. In 20/20 hindsight, it may have been better to attempt to save two lives for the price of one.

MANUAL

Even a roll cage is of little use against excessive force. Remarkable!

Bob Rouleau

Manual - if the circumstances are as we think (only a hypothesis, really) then the best course of action would be to gently steer around the obstacle. The next best would have been to go hard on the brakes and .....bang - smack the other car. Hitting another car moving in more or less the same direction is quite obviously "softer" than a concrete wall. The speed differential is far less between the CGT and the Ferrari (kinetic energy is 1/2 Mass x Velocity SQUARED) and the Ferrari would exhibit far less resistance than the wall. It is so sad that the outcome was different from our theorizing.

Regards,

Les Quam

As much as I hate to agree with Alex on anything (LOL) I have to in this case. If a guy drives out from pit lane in front of me on the track my only concern is surviving the incident not his or her well being. Sad as that it is I think it's an on track reality.

PogueMoHone

The Ferrari and it's driver could likely be a "red herring" in the whole scenario, and not worth speculating about. He apparently did nothing wrong in coming on to the track, using the space assigned for that purpose.

Only one thing is for sure:

A driver, with a passenger, on the the track travelling a high rate of speed, lost control of his car, with tragic consequences.

If you want to play probabilities, then most likely he was distracted and over-reacted (over corrected).

Questions to be addressed and answered (best left to the lawyers and Judge):

Did he talk a better game than he drove?
Was he too inexperienced to handle "track" activities and traffic?
What was his training, amateur or professional?
Was he talking to his passenger?
Was he showing off?
Was he going too fast for the conditions?

Not stuff we like to think about, but stuff we should never forget, because we are all human and can get caught up in the moment. I think we all had our lucky escapes, and unfortunately some are not so lucky!

MANUAL

On the track, who is supposed to yield the right of way: the car on the track or the car entering the track from the pit?

Was there a clear blend line or a yield sign?