Roadkill trajectory

June 19, 2009 10:23 AM

Why are there so many more corpses on the shoulder than in the middle?

'tis the time of year in Canada to see lots of dead porcupines and raccoons during highway driving. Why are so many more seen beside the highway rather than on it? Is it a simple physics trajectory/probability thing? Are they dragged to the shoulder by concerned drivers or gangs of African swallows with strings? Do they crawl there before expiring? Do the ones left on the highway disappear faster due to heat and friction?

posted by fish tick to Travel & Transportation (17 answers total)

Some people stop and move the corpses off the road. This prevents scavengers who come to eat the corpse from also getting hit.
posted by Lobster Garden at 10:24 AM on June 19, 2009

Partly people or crews moving the roadkill, partly that corpses in the road are pretty quickly smeared out and ground away to nothing.
posted by chrisamiller at 10:26 AM on June 19, 2009

I have no basis whatsoever for the following assumption; An animal detects an oncoming vehicle and attempts to flee. It will choose the path that takes it to safety fastest (the woods). It severely misjudges it's ability to escape and is hit mid dash-for-safety. So perhaps most animals are hit while already heading for the shoulder and it's rarer to catch one that will stand there all deer-in-the-headlights like?
posted by syntheticfaith at 10:42 AM on June 19, 2009

The ones squished in the middle of the road are easy pickings and so first to be eaten.
posted by weapons-grade pandemonium at 10:43 AM on June 19, 2009

On my way to work this morning, I drove over a freshly-killed raccoon that was lying in the middle of the road*. I'd bet $100 it won't be there when I go home.

*I felt badly even though it was already dead, but in order to avoid it I would have had to swerve into oncoming traffic.
posted by desjardins at 10:46 AM on June 19, 2009

Also, it can take a little while for an animal to die after getting hit by a car. Some will make it off of the road after being hit and lay down to die on the shoulder.
posted by originalname37 at 10:55 AM on June 19, 2009

A lot of animals actually get hit by the car as opposed to get run over by the tires. The impact sends them flying through the air and because they usually get clipped they get flung to the side onto the shoulder.
posted by Vindaloo at 11:01 AM on June 19, 2009

The one time I hit a deer it was running across the road and its momentum carried it in the direction of travel all the way to the other shoulder; I would guess most animals are moving across the road when hit as very few would just sit there waiting for the impact. Also, some car-animal impacts are at an angle and so will tend to knock the animal off to one side or the other. Having said that, I see a fair number of dead animals in the middle of the road as well. I imagine a number of the factors mentioned above come into play as well.
posted by TedW at 11:02 AM on June 19, 2009

Some of it has to do with the impact. See "Google car hits Bambi" for details - they hit the deer in the middle of the road and it ends up on the shoulder.
posted by sephira at 11:12 AM on June 19, 2009

I move corpses off the road when I can, though not on highways usually. I value my life too much.

The reason why I move them is mentioned above - particularly because one of my favorite birds, the red-tailed hawk, likes to feast on roadkill. The juveniles, in particular. And because they're inexperienced teenager birds, they often misjudge how quickly they'll have to take off to avoid oncoming vehicles, so they clear the car, but not the semi behind it.
posted by HopperFan at 11:26 AM on June 19, 2009

I don't have much insight into the flight paths of large or small animals, but I worked for a suburban health department for a few summers in college and we'd shovel up the roadkill, throw it in the back of the truck, and put it in a deep freezer back at the garage. We never just moved it to the side of the road. Because it was suburban, it was small things like squirrels, rabbits, possums, etc. though we did deal with the occasional deer.

I can't say for sure because it wasn't the way we did things, but I feel like I remember hearing about how other health departments or even state troopers will just move larger stuff to the side of the road/highway to keep it from causing accidents.
posted by dyobmit at 12:12 PM on June 19, 2009

Like others mentioned above, if I hit something, I'd move it to the side of the road to avoid birds of prey being hit by cars.

I don't think this has much to do with flight paths of dead animals.
posted by twirlypen at 12:47 PM on June 19, 2009

Because it's less likely to be hit again on the outside edge of the road. Garbage, rocks, roadkill, and whatever else will be flung more or less randomly by a passing car. If it lands in the middle of the road where it will be hit again, it is again flung at random. The process repeats until it lands in a place where it is out of the way and not hit again.
posted by JuiceBoxHero at 4:23 PM on June 19, 2009

Not wishing to be pedantic, but a corpse is a dead human body, which makes your question sound rather alarming. A dead animal is a carcass.
posted by idiomatika at 10:29 PM on June 19, 2009

Yes, JuiceBoxHero has it. That is also why most of the broken glass / random sharp debris / slippery piles of wet leaves are on the shoulder rather than in the road, and when bicycling one will often need to be in the road rather than on a shoulder in order not to get a flat or even worse, lose traction on wet leaves or gravel and crash.
posted by idiopath at 10:39 PM on June 19, 2009

1 archaic : a human or animal body whether living or dead
2 a dead body especially of a human being [emphasis mine]

So the OP wasn't entirely incorrect. Would depend on the context, I'd think, and no one here thought that the question was referring to human bodies.
posted by HopperFan at 11:24 PM on June 19, 2009

I clicked through because I thought it was dead people!
posted by Lesser Shrew at 12:02 PM on June 20, 2009