ProCoach

That's why I said that it was from a manufacturer's site, obvious bias at the end, but still interesting.

Here's additional insight. Still a commercial site but more wide ranging info. http://www.impactsafetybarriers.com/...Comparison.pdf

My thought is that the the segmented concrete barrier is actually an impact attenuator, by virtue of its movement in the OP's case.

endoquest

I was in the pits fairly close to the crash. Didn't see anything happen but heard the hit, it sounded quite serious. After the car came back I talked to the owner as he was winching it up a trailer. The cage looked really good. The fiberglass door was completely gone but the x-frame inside, right where the impact was, appeared straight. The welds were good too. I asked the owner who built the cage. Racetech Motorsports was his answer. I've heard of them before and they're local to Portland. Good job guys!

TXE36

That description makes me think it was not a rear trailing arm pocket failure. The rear suspension on these cars has an upper control arm, a simple lower control arm, and a trailing arm. The wheel folding into the fender and rotating out indicates the failure was not in the trailing arm but in the support for the spring. When the trailing arm fails there is nothing to keep the rear suspension from twisting around with the wheel, so the suspension twists off and the wheel departs - see the next quote:

Now that looks like a trailing arm failure. Note that the OP did not roll.

Sometimes I think I would be a faster driver if I didn't know about these mechanical weaknesses in the platform I drive...

-Mike

Akunob

ProCoach

Frank 993 C4S

Wow - big hit. To the OP, glad you are ok!

Makes me wonder about these arrive and drive deals where you really don't know the history and maintenance condition of the car.

fatbillybob

Joe Marko @ HMS agrees. He has also posted a few times on how rollbar in streetcar and your head issue is a red herring. A properly padded bar is not different than OEM padded A-piller or anything else you can hit. It is also true that having your head on a padded bar is not as bad as allowing your head to accelerate into a bar multiple inches away. So 1st choice is be far enough away from any bar to hit. Second choice is to be right on the bar. 3rd choice is being far enough away to be whipped into the bar upon impact.

Pruettfan

Happy your OK, yes you can get a concussion without hitting anything, the simple act of sudden decelleration can be the culprit because the brain continues to move until it hits the inside of your skull. Having said that I think it is prudent to get a new helmet rather than taking any chances. As you have stated your safety equipment saved you so don't that the chance of having a potentially compromised helmet. They aren't cheap but you can't buy a new head or brain.

Manifold

That document is a step in the right direction, but it's odd how they use some incorrect terminology, are missing key information, and get some things wrong. It seems that the "outside firm" they hired didn't really have expertise in this area and mainly just gathered info from internet searches.

If a barrier is intended to absorb energy by moving, you generally want to absorb energy by deformation of material, as parts of a car do when they crumple. With a 'segmented' concrete barrier (segments pinned together), the rigid segments aren't deforming and energy absorption is mainly due to sliding of the segments across the ground, which is a limited and somewhat unreliable way to absorb energy. Such concrete barriers are used in temporary roadway applications, and the intent is for them to move as little as possible. When concrete barriers are used in permanent roadway applications, they're prevented from moving by being anchored to pavement or placed on concrete footings. In my three decades of experience designing runoffs and traffic barriers as a professional engineer, I've never seen a concrete barrier intentionally designed to move. The SAFER barrier essential combines a flexible barrier in front of a rigid concrete barrier, and was properly engineered to do so.

Manifold

Agreed on the first choice. You don't want to be hitting hard things inside the car when flailing around in a crash - that's why cars have airbags. The second choice is neither desirable nor really even a choice - in a crash, due to the body flailing around, it's not possible for the head to stay 'right on the bar'.

ProCoach

Manifold

Fully agreed. As I've said many times in many threads, there are widespread safety deficiencies at tracks. There are several reasons:

- Unlike roadways, tracks are unregulated and there are no mandatory standards and guidelines for tracks (the ISS document is an unusual step to at least try to provide some guidance). Track owners pretty much do what they want with safety, unless track renters pressure them to do otherwise.

- Track owners typically lack expertise in this area, and often don't hire people who do have that expertise. This is partly because they don't know what they don't know. But also, if they hire a professional engineer like me and I recommend X and Y, and they don't follow my recommendations, that can increase their liability.

- The cost of making safety improvements can be substantial, and there's lack of incentive to spend that money if track renters aren't complaining, since waivers provide significant liability protection for track owners, and they have insurance if they do get sued and need to settle or go to trial.

Probably apropos to share this again: http://bobstracks.squarespace.com/im...at-tracks.html

CosmosMpower

That looks like a serious hit, glad you walked away and the owner was cool with the fairly sizable write off since it wasn't your fault.

Jimbo951

I'm not an expert on these cars, but I'm seeing something different from the pics.

The inside sidewall of the tire is completely trashed. If the suspension failed, I would have thought it would have unloaded the tire and then when the driver hit the brakes, it would have locked the tire (like the observer stated). I would not have expected the sidewall of the tire to be destroyed.

Maybe the earlier repair was no good and it slowly cut down the sidewall. Then a slow leak developed and that impacted the handling. Finally the whole tired failed and that started the accident.

Just my $0.02.

38D