(no subject)

[theweaselking]

Anatomy of a car crash: what happens in the first 70 ms after a side impact.

(Note that it's about 150ms before they reach "Occupant becomes aware of collision.")

Comments

[publius1.livejournal.com]

That's assuming 50km/hr. What if it's the much-more-likely 110km/hr?

[anton-p-nym.livejournal.com]

That test is talking about a side impact, not a head-on collision. I can see getting t-boned at 110km/h, but can't see it being "much-more-likely". Besides, not all driving is highway driving.

-- Steve's sole accident occured when he was driving at 0km/h*, and a great many accidents happen at traffic intersections or in urban areas.

* while I was stopped behind another vehicle that was waiting to make a left, an idiot pulled out of a parking lot and rear-ended me.

[theweaselking.livejournal.com]

I liked your much-more-entertaining first comment. Why yes, I REGULARLY fire my Ford Falcon out of a monstrous railgun, doesn't everyone?

Really short version: The force applied to bring your car to an abrupt stop in zero distance is the same no matter whether you're stopping because you hit an immovable object or a movable one. If what you hit is a giant truck that keeps moving and suddenly it's not just "I stopped" but "I stopped and then started moving backwards at 50km/hr", that's different, but hitting a stone wall at 50km/hr and hitting an identical car headed in the other direction at 50km/hr will apply the same force over the same time to your car. Hitting a STOPPED car is better, but that's because the other car starts moving and thus your car doesn't come to a complete stop in that same zero distance.

Also: Most SIDE impacts do not involve you going sideways at 55, or the guy driving into your side going 110.

[publius1.livejournal.com]

Well, that's non-intuitive, ain't it? You'd think that the relative speed of the car would have something to do with the kenetic energy.

[theweaselking.livejournal.com]

It does! The thing is, an immovable wall hits you back *exactly as hard as you hit it*.

[publius1.livejournal.com]

Ah yes, good ol' equal'n'opposite.

[theweaselking.livejournal.com]

Isaac Newton is the deadliest son of a bitch in space.

[theweaselking.livejournal.com]

Also: You have twice as much time to see a stone wall coming as an oncoming car moving at your own speed. Which is a very real difference!

[aeduna.livejournal.com]

That's the default suburban speed in the state the paper is printed, they might have chosen it for that reason. Its the speed you'd probably be going in your street before going onto a main road.

[skreidle.livejournal.com]

Also, side impacts are the hardest to safely counter; front and rear have a lot more car to collapse in order to slow the impact.

And you're more likely to be t-boned at suburban speeds by a tool running a stop sign. :)