What's better: hitting a car or hitting the ditch?

December 17, 2006 4:58 PM

What kills people when they drive into the ditch? Is it rolling over, or just the high speeds of the highway?

I often imagined I would make a play for the ditch in some crazy highway near-accident scenario, but I always hear of people getting killed when their car goes into the ditch. What gives? Those ditches look like a much softer landing than another vehicle... I could see if I went at speed into the bank of a ditch, but what about just making a smooth slide into the gutter to use a bowling analogy.

posted by dino terror to Travel & Transportation (17 answers total)

If you did a "smooth slide into the gutter," you'd probably flip over. Plus, yeah, when you hit the far bank, you go from whatever your speed is to zero in a hurry.
posted by I Am Not a Lobster at 5:03 PM on December 17, 2006

I think the problem is that, when your car hits the ditch, the ditch stops the car, but it doesn't stop your body, and your body gets very fucked up as a result. It doesn't matter whether the thing that stops your car is a ditch or another car---your body keeps moving. Seatbelts and airbags do help, though.
posted by jayder at 5:04 PM on December 17, 2006

It's not the fast slide, but the sudden stop that kills you.
posted by JujuB at 5:09 PM on December 17, 2006

Going to the side of the road could save your life or end it. It depends on what you find there.

You would prefer to enter a shallow ditch rather than a deep one. You would want to enter the ditch at an oblique angle and avoid any culverts. Shallow water is your friend. Deep water is to be avoided. You would want to hit a stand of small trees rather than one large tree, etc., etc.
posted by yclipse at 5:41 PM on December 17, 2006

I believe that some that hit the ditch had already had a heart attack and that caused them to hit the ditch.
posted by JohnnyGunn at 6:42 PM on December 17, 2006

With the exception of freak events like getting decapitated by a piece of wreckage it's the decelleration trauma (directly or indirectly from shock/blood loss) that kills most auto accident victims. And 19 times out of a 20 you are much better hitting the ditch than an oncoming car. This is because you shed speed a lot slower in the ditch, even if you roll, than if you were to hit another car head on. Lower decelleration, less decelleration trauma. The 1 in 20 is when you end up upside down in a water filled ditch, hit a culvert/abutment or get impaled by one of those road side crosses or something.
posted by Mitheral at 6:44 PM on December 17, 2006

What kills you is:

1) Decapitation, crushing, perforation, dismemberment, resulting blood loss, shock.

2) Deceleration of your internal organs.. in every collision there is the impact of your body, then the secondary impact of your still moving organs hitting your body. You can't see those bruises.

The amout of energy to be dissipated is substantial. A head-on is worse by far than a ditch landing, if the ditch is not a stone wall or does not contain something that will stick into your vehicle. I would choose it over most headons, like I have a choice!

But I would! If there's any chance guiding the vehicle to a controlled stop and deceleration, upright, that's my choice.
posted by FauxScot at 6:46 PM on December 17, 2006

Often times it's the traumatic aortic disruption. Stuff that's in motion staying in motion until it encounters something - in this case, your rib cage.

Like the others have said.. it's the sudden stop at the end. You stop moving before your inner bits stop moving. Stuff tears, you bleed out.
posted by drstein at 6:58 PM on December 17, 2006

Don't forget drowning, those ditches sometimes have water in them, and your car can end up upside down.
posted by tiamat at 7:15 PM on December 17, 2006

And remember to wear your seat belt when you drive into the ditch. You don't want to be outside of the car when it's "slowing down gradually".
posted by smackfu at 8:05 PM on December 17, 2006

Ditches are safer if you can keep calm. If you keep your wheels as straight as possible and wale on the breaks, you wont roll over. Stopping distance is worse in the grass, but as long as you keep going straight as an arrow, it will end well.

Improved, modern highways have graded and drained ditches. you stand a MUCH better chance doing a straight shallow-angle plow into the ditch compared to running into another car or a barrier. This depends on you having time to make a controlled entry to the ditch, though.

If you are in a situation where you must make a sudden wheel rotation to avoid something, you're well and truly fuxored, and the right answer depends on your luck at that precise moment.

The very best thing to do is not drive excessively fast! Every tiny bit of extra speed you have extends your breaking distance considerably. Breaking power is linear and momentum is exponential. If you are on a road and feel you wont be able to stop in time if something stationary was on the road (like an accident or a deer) then slow down a bit.
posted by clord at 8:09 PM on December 17, 2006

This is because you shed speed a lot slower in the ditch, even if you roll

Minor quibble: rollovers can result in a lot more impacts to a lot more parts of the body (with a lot more resulting secondary organ collisions) than a single-impact crash.
posted by mediareport at 9:00 PM on December 17, 2006

"Minor quibble: rollovers can result in a lot more impacts to a lot more parts of the body (with a lot more resulting secondary organ collisions) than a single-impact crash."

But isn't each of the multiple impacts substantially less forceful than the single impact? One of the cliches I remember from when old what's his name was killed in a NASCAR race was that the crashes with multiple flips were less scary for people in the know than the ones where the car just slams in to something and stops. I suppose in the interior of a real car there's probably a lot more crap flying around to cause damage, but barring a backseat full of loose bricks, the theory makes sense to me.
posted by jaysus chris at 6:46 AM on December 18, 2006

But isn't each of the multiple impacts substantially less forceful than the single impact?

Yes, of course "just slamming into something and stopping" is more forceful than any kind of crash that lets you keep moving; that was in Mitheral's comment (the one I was replying to). I just wanted to note an additional complicating factor in rollovers as opposed to going into a ditch without rollovers. You're more likely to have multiple body system injuries after a rollover crash, since every surface and object inside the car becomes a potential weapon.
posted by mediareport at 6:54 AM on December 18, 2006

I've skidded into the snow-covered median ditch of an interstate highway at over 60mph. I didn't die or flip my van. The snow helped to slow me down but generally a ditch doesn't slow you down that fast to cause any injuries. At most if you flipped it you could expect some whiplash.

Now if you hit something solid like another car or a bridge abutment, you could expect massive internal injuries. If you flipped your car without a seatbelt on, you should expect to be catapulter from the vehicle and most probably have it roll on top of you. Without hitting anything and with your seatbelt on, you should expect to easily survive an offroad rollover accident in nearly any type of car unless your speeds are in excess of 100mph. Of course, there are always freak accidents which take the life of people when they normally shouldn't.
posted by JJ86 at 7:01 AM on December 18, 2006

Without a seatbelt, people are often ejected from a rolling vehicle. That decreases the odds of survival.
posted by atchafalaya at 9:03 AM on December 18, 2006

jaysus chris writes "One of the cliches I remember from when old what's his name was killed in a NASCAR race was that the crashes with multiple flips were less scary for people in the know than the ones where the car just slams in to something and stops."

Dale Earnhart experienced a basal skull fracture when his car slammed into the wall and stopped dead rather than just skidding along it. Interestingly he might/probably would have survived if he'd been using a HANS device in conjunction with his helmet or if Winston cup cars had more crumple zones ala F1/CART engineered into them.
posted by Mitheral at 10:50 AM on December 18, 2006