Hacker News Reader

Comment by userbinator | Hacker News Reader

Several bystanders managed to push the car backwards, police said, but "in the course of doing so, the vehicle rolled forward once again and pinned the pedestrian between the two vehicles once more."

...and with even more force, since the car now had a bit more distance to build up some speed. One wonders whether he would've survived if they had left him there, and it was the second blow that killed him, since the fact that they were able to push it back suggests it was probably an automatic left in neutral with nothing more than the idle torque. If it was a manual, stopping it or pushing it backwards would've already stalled the engine. I suppose another lesson here is that if you ever have to push a car out of the way, chock the wheels afterwards, or otherwise try to prevent it from moving again.

I'm also surprised that was enough to kill.

Edit: downvoters, explain yourselves please.

View on HN

Emergency Medical Technician here (from France). Disclaimer: I'm just speculating as I have no specific knowledge of what happened in this particular accident.

Depending on the height of the bumpers involved, I would suspect several possible problems: one or both femoral arteries severed; or both femurs fractured; or the pelvis fractured; or some combination of these.

Even if the arteries were untouched, fractures of both femurs or the pelvis cause life threatening blood loss as these are heavy bones which have major vascularisation (to allow blood cells generated in the marrow to enter the blood stream). A closed femur fracture is a 1000 mL to 1500 mL loss of blood (per femur). An open femur fracture is double that. A pelvic fracture can go to 5000 mL (approximately the total volume of blood in the average adult male).

In the field, major lower limb arterial bleeding can be controlled with tourniquets; femur fractures can be somewhat reduced with traction splints; pelvic fractures can be somewhat stablised with pelvic compression devices... However all of these scenarios are bad news for the patient and require rapid evacuation and surgical intervention (ideally in less than 1 hour from the time of injury) to have a chance of saving the person's life. RIP and condolences to patient's family.

Here's a picture of a person standing next to a 2002 is300: http://www.billswebspace.com/lexus2.JPG

Looks like it would pin you just above the knees if you were her height.

I agree the victim was probable pinned at knee level for the initial trauma. However according to the article, bystanders were able to push the car back and then it rolled forward again pinning the victim a second time. Given that he had just (probably) had his knees injured, it's possible he was much lower to the ground during the second impact: if he were sitting or crouching, then he could have suffered pelvic, abdominal, or thoracic injury, all of which are life threatening. Anyway, all of this is speculation without confirmed details.

(Edit: typos.)

One added datapoint (not sure how accurate, but it sounds consistent): according to a BBC report of the incident [1], "Mr Kosanovich was taken to hospital with severe trauma to his torso and legs".

[1] https://www.bbc.com/news/technology-50756243

The creep you're referring to in an automatic is in drive (or other modes besides park and neutral). Neutral functions similarly to neutral on a manual transmission car.

There's no solid coupling, but in neutral the viscous drag through the clutches (especially when the fluid is cold) is often enough to transmit some force to the output shaft; and as anyone who has pushed around vehicles on a flat level surface would know, it doesn't take that much force to start a car rolling. However, stopping one that's moving even very slowly with no actual power behind it is surprisingly hard due to the inertia alone (I've manually moved around cars in a shop before, and had my fair share of bumps and bruises --- no crushes, fortunately.)

After having your legs crushed and someone freeing you, I would imagine your first action would be to sit down.

Then the person pushing the car back gets tired (since they are pushing against an automatic cars 'creep' torque converter), and the car comes back at you again, this time crushing your head.

I can see how that's deadly.

Or more sinister: the pinned car could have acted as a tourniquet, and once it was removed the pedestrian could have been free to quickly bleed out.

I think it’s not surprising having your legs crushed can kill you. All your blood flows through there!

Yes to the chocks, although it's worth noting that in a crush situation you should aim to remove the crushing object within 15 minutes. Any later than that and you risk killing the casualty through crush syndrome.[0]

[0] https://en.wikipedia.org/wiki/Crush_syndrome

If it was a manual the car wouldn't have even been able to start. If you are in gear the clutch needs to be disengaged to start the car, otherwise the engine can't spin as it's connected to the wheels through the transmission. That's why if you bump start a manual you need to get the car rolling in neutral with some speed first, to make the engine spin when you put the car in gear and engage the clutch.

A manual could start in neutral without the clutch, but if it somehow slipped into gear (don't see how that's possible without someone forcing the stick), it would stall immediately.

> Edit: downvoters, explain yourselves please.

You're accusing good samaritans of killing someone - with no evidence to indicate that this was the case?

He didn't accuse anyone- he simply wondered whether it could have been the second impact that was fatal. Even if it were, that's still not an accusation, just an unfortunate accident.

How far do you reckon they pushed the car?

Reply on news.ycombinator.com