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Robocars vs. Deer and the flying bumper


Today, I was challenged with the question of how well robocars would deal with deer crossing the road. There are 1.5 million collisions with deer in the USA every year, resulting in 200 deaths of people and of course many more deer. Many of the human injuries and crashes have come from trying to swerve to avoid the deer, and skidding instead during the panic.

At present there is no general purpose computer vision system that can just arbitrarily identify things -- which is to say you can't show it a camera view of anything and ask, "what is that?" CV is much better at looking for specific things, and a CV system that can determine if something is a deer is probably something we're close to being able to make. However, I made a list of a number of the techniques that robots might have to do a better job of avoiding collisions with animals, and started investigating thoughts on one more, the "flying bumper" which I will detail below.

Spotting and avoiding the deer

  • There are great techniques for spotting animal eyes using infrared light bouncing off the retinas. If you've seen a cheap flash photo with the "red eye" effect you know about this. An IR camera with a flash of IR light turns out to be great at spotting eyes and figuring out if they are looking at you, especially in darkness.
  • A large number of deer collisions do take place at dusk or at night, both because deer move at these times and humans see badly during them. LIDAR works superbly in darkness, and can see 100m or more. On dry pavement, a car can come to a full stop from 80mph in 100m, if it reacts instantly. The robocar won't identify a deer on the road instantly but it will do so quickly, and can thus brake to be quite slow by the time it travels 100m.
  • Google's full-map technique means the robocar will already have a complete LIDAR map of the road and terrain -- every fencepost, every bush, every tree -- and of course, the road. If there's something big in the LIDAR scan at the side of the road that was not there before, the robocar will know it. If it's moving and more detailed analysis with a zoom camera is done, the mystery object at the side of the road can be identified quickly. (Radar will also be able to tell if it's a parked or disabled vehicle.)
  • They are expensive today, but in time deep infrared cameras which show temperature will become cheap and appear in robocars. Useful for spotting pedestrians and tailpipes, they will also do a superb job on animals, even animals hiding behind bushes, particularly in the dark and cool times of deer mating season.
  • Having spotted the deer, the robocar will never panic, the way humans often do.
  • The robocar will know its physics well, and unlike the human, can probably plot a safe course around the deer that has no risk of skidding. If the ground is slick with leaves or rain, it will already have been going more slowly. The robocar can have a perfect understanding of the timings involved with swerving into the oncoming traffic lane if it is clear. The car can calculate the right speed (possibly even speeding up) where there will be room to safely swerve.
  • If the oncoming traffic lane is not clear, but the oncoming car is also a robocar, it might some day in the far future talk to that car both to warn it and to make sure both cars have safe room to swerve into the oncoming lane.
  • Areas with major deer problems put up laser sensors along the sides of the road, which detect if an animal crosses the beam and flash lights. A robocar could get data from such sensors to get more advanced warning of animal risks areas.

Getting the deer to move

There might be some options to get the deer to get out of the way. Deer sometimes freeze; a "deer in the headlights." A robocar, however, does not need to have visible headlights! It may have them on for the comfort of the passengers who want to see where they are going and would find it spooky driving in the dark guided by invisible laser light, but those comfort lights can be turned off or dimmed during the deer encounter, something a human driver can't do. This might help the deer to move.

Further, the car could emit loud sounds. There should be study of what sounds are best at scaring deer -- though we don't want to scare other deer onto the road. There might also be other light patterns that scare, rather than transfix a deer.

An extreme step would be to arm the car with a plastic BB gun (sometimes called airsoft.) Ok, you're thinking, are we going to arm robots already? But a plastic BB in the rump might be just what is needed to get the deer to jump away. Clearly we need some good safety around such a weapon, and might even insist that the human passenger pull the trigger.

A research project to learn what combinations of lights, sounds and even plastic BBs do the best job of reliably scaring deer off the road sounds like a good idea. Reportedly, while they sell devices that make an ultrasonic noise, they do not work according to insurance reports. I would presume something that sounds like a cat or other predator would be a good goal. Electric vehicles will be making minimal noise.

Hitting the deer

If all the above fails, the car may hit the deer. In particular if the deer suddenly jumps out onto the road from a place where it could not be seen, you might still hit it even at a good speed. (If it's further down the road, the impact would be slow.)

The deer weighs as much as 300lb. Moose and some other animals can be even bigger. Smaller deer will damage the car but should not cause an accident for a robot driver. But there can be lots of damage. And in some cases, deer fly up and go through the windshield, resulting in major risks for the people inside.

One immediate thought is that robocars don't need to have windshields at all, though passengers will like them for the view and to eliminate motion sickness. However, they don't have to be big wide windshields with no obstruction. They could be made out of panes with strong bars between them. Alternately, a grid of metal bars could come up in front of the windshield when traveling in deer country. Or if they can be raised quickly, the bars could snap up just before any crash. (This could be added to a human driven vehicle as well.) Compressed air can accomplish such a quick deployment. The robocar will know at least a second in advance in most collisions.

There is of course the problem of what passengers do during a sudden stop or worse, an impact. In a multi-person robocar, half the passengers will be facing backwards in most cases, and they will fare better. The stop will be quite disturbing to the forward facing passengers. The use of seatbelts would be strongly recommended while moving at high speed through deer country at the busy crossing times. If necessary, the car will always be monitoring the passengers in such situations and firing airbags to protect them in case of impact.

In a non-impact situation at lower speeds, the robocar would of course reduce the braking and even give audible warning before doing it.

Flying Bumper

Another approach, valuable in any sort of collision, is what I will call a "flying bumper." This is a bumper which is mounted on two long pistons. A blast of compressed air is able to send the bumper out so it moves 2 meters in front of (or behind) the car. The bumper is then able to be pushed back into its pistons, resisted either by compressed gas, springs or even metal forms being destroyed. This adds 2 meters of travel in which to accomplish a large fraction of the total deceleration of the impact. After the bumper returns to the car, it then presses against the car's regular crumple zones, which absorb as much of the impact energy as they can.

The extra 2 meters (or possibly 3 or 4 on longer cars) could mean a huge difference in the amount of shock the passengers (and car, and deer) are subject to. A life and death difference even with high speed collisions with solid objects, let alone deer.

If the collision is to be with another car equipped with a flying bumper, then a total of 4 meters of extra travel could take place. Suddenly even a head-on collision or brick wall collision is much more survivable.

Such a system could go on a human driven car. The trick is to have a computer system which is able to reliably detect an impending accident and to work out precisely when impact will occur. That can be done even if a human is at the wheel, and technologies that do variants of this, like Mercedes Pre-Safe, are already on the market. But key to this approach is the knowledge that even if a robocar might get into a collision, it will very rarely get into one it doesn't know is coming well in advance. At least well in advance for a computer.

This bumper can also have airbags in it. Airbags not for the passengers but for the person, animal or even other car being hit. Again, knowing the moment of impact allows the computer to fire the airbag before the impact and soften the blow. This is particularly important if it's a pedestrian being hit. Airbags might also solve the windshield problem, in that an airbag that explodes in front of the windshield just before the deer hits it might disperse the force over the whole windshield, and soften the impact. Airbags are currently expensive because of the safety constraints of the job they perform.

The bumper could also be set so that one side comes out further than the other, creating a diagonal bumper which directs the deer away from the car instead of trying to throw it in the direction of travel. The robot should be able to compensate for those forces.

The flying bumper seems very valuable to me, though I do see one problem with it. We must work very hard to assure it never triggers at the wrong time, particularly if a car is stopped. You want a fail-safe that can prevent that. One way to do that might be to only charge the compressed air tank that pushes out the bumper with a pump driven from the drivetrain while in motion, and dischrage that tank when stopping. That's a bit wasteful of energy, but there might be a way to have a fail-safe system that controls where the compressed air can go based on movement.

Today a computer can't, like a human, just look out into the world and tell what everything is, including a deer by the side of the road. However, the above techniques suggest it doesn't need to. (Some day it will be able to, adding even more ability.) In many ways I believe the robocar should actually do much better at detecting and avoiding deer, particularly in the dark.


i have thought about a similar design in terms of flying bumpers.
The main difference is I imagine them to just always be deployed at highway speeds.
There is no problem with accidental deployment as they just go out slowly.
The main tricky bit will be aerodynamics but perhaps with a folded faring it could bemade even more aerodynamic than a normal car.
Of course this would work for humans and robots alike.

I am not sure you could avoid a large energy cost on this. One would also have to retract it if joining a robot convoy where the cars are drafting for efficiency. (Possibly -- there are arrangements where 2m or so spacing is reasonable for that.) Slow deployment does solve the problem of accidental deployment but is a bit more expensive and there will be breakdowns that need fixing. A system that deploys only in an accident does not even need a way of being reset automatically, you need to go to the shop to get it reset. It would ratchet out and then become connected with the thing it is going to compress to store the energy. Recompressing gas, which turns the energy into heat would be nice but I am not sure it can absorb as much energy as bending springs or other metals etc.

This is a variant of the jay walking pedestrian problem.

While it would be nice if RoboCars could eliminate deer (or in Canada, Moose) collisions, in point of fact RoboCars only have to do at least as well as humans.

Reducing collisions or reducing damages from collisions probably can be done. Most likely eliminating them entirely is (like all engineering tradeoffs) either virtually impossible or highly impractical or too expensive (or all three.)

Fast, cheap, reliable .... pick any two.

Complete elimination of collisions is indeed difficult. However, nor is it to simply do as well as humans. I doubt that we would get many legal jurisdictions to accept the vehicles if they were that bad. There's no history of other automated systems being accepted at that level. They have to do much better than humans. But much better than humans is still far above zero, sadly.

In the very long term, with no human drivers left on the roads, I think we would get pretty close to zero, though there will still be mechanical failures, suicides and completely reckless behaviour by cyclists and pedestrians, things falling off the back of trucks and such to stop it from hitting zero.

Whether we can get to zero in bad weather is more difficult. We do insist in going faster in bad weather than we really should from a safety standpoint. We will probably continue to insist on that.

Here in Texas, the most common dog is the black Labrador Retriever. And Labs are great jumpers and diggers, so they often escape backyards. It's not as bad as the fabled coal mine, but a black dog on a blacktop road during a moonless night is a serious challenge. Infrared sensors are not that useful in summertime when the road temperature can reach 150 degrees F. and retain a lot of heat after sunset.

As for "flying bumpers", it sounds like you've just reinvented the cowcatcher that made 1880's steam locomotives so picturesque.

Is there a big problem of collision with dogs? I presume they don't do the "deer in the headlights" thing so much, they tend to understand roughly what cars are. For better or worse, the goal here is to prevent collisions which might harm humans and vehicles -- protecting the animals is worthwhile, but secondary.

The deep infrared sensing would not be to see the deer on the road -- the LIDAR (which runs in near infrared) will see that and the eyes will also glow in near infrared. Deep infrared would be to spot deer in the bushes at the side of the road, to know when to slow and track them and be ready (or to do further identification.) Deer move in groups so it is also good to spot them on the side of the road even if they already crossed.

The cowcatcher was a fixed device, and it was intended to divert the object on the rails away from the train, not really to absorb impact by compressing as I propose for the flying bumper.

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