Self-Driving Cars Need To Watch Out For Flying Debris

Dr. Lance Eliot, AI Insider

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(Ed. Note: For reader’s interested in Dr. Eliot’s ongoing business analyses about the advent of self-driving cars, see his online Forbes column:

I was driving on the freeway the other day and up ahead of me the traffic started to do all sorts of dodging and weaving.

As I strained to see what was going on, I could just barely see white objects of maybe a half foot in length that were in the air and seemingly randomly bobbing around at the height of the car hoods and windshields. The act of the drivers swerving their cars had made the situation dicey and I was anticipating that some cars would ram into each other while playing this high-risk dodge game.

Upon reaching the point at which the objects were floating around, I was able to determine that they were actually pieces of mattress stuffing.

Apparently, a mattress had fallen down onto the freeway, cars had hit and exploded open the mattress, which then disgorged the innards and the stuffing was being carried up into the air by the motion of the cars.

Roadway Debris Consternation

Debris is always a potential issue for drivers as to whether to hit it or try to dodge it.

There’s the type of debris that sits on the actual roadway and driver’s need to determine whether to hit it, or try to roll over it, or try to avoid it, all of which is tied to what damage the debris might cause to the underbelly of the car and whether or not the car will be able to continue unabated after striking the debris.

Besides debris on the roadway, there’s also airborne debris.

This flying debris can originate as roadway debris, including the example earlier of a mattress that fell onto the freeway and then got split open after some cars hit it. The resulting spray of the mattress stuffing became an airborne mess. Car after car was making the material become increasing airborne and it was flitting back-and-forth across the lanes of traffic. In this case, the fluff was harmless, but the drivers were reacting to it anyway as though it was something that could harm their cars.

That’s a natural reaction for drivers. If they aren’t sure of what it is, they are going to try and avoid it.

Special Attributes Of Flying Debris

In fact, I’d assert that we have a natural aversion to anything that is flying towards us menacingly.

Flying debris can appear seemingly out of nowhere and originate via other means. A few years ago, I was driving along, minding my own business, when all of a sudden a golf ball struck my windshield.

Some drivers might have reacted and maybe gotten themselves into deeper trouble by swerving into other cars or possibly even driving off the highway and into a telephone pole.

How do human drivers react to flying debris?

Sometimes they swerve to try and avoid it. Or, they might hit the brakes in hopes of not striking the flying debris.

Or, try to accelerate and get under it before it can land onto their cars.

There are even some drivers that they themselves duck their heads and lose control of their cars, reacting as though the flying debris is going to physically harm them. Sometimes a driver just freezes up and slams into the flying debris.

Factors And Driver Reactions

Via hindsight, you could say that the drivers that swerved to avoid the mattress fluff were wrong and perhaps “stupid” for having endangered other cars when they instead could have just driven straight into the stuffing.

This is a hard call to make, though. At the moment of seeing the debris, you often have just a split second to decide what to do.

There are a multitude of factors that come to play in dealing with flying debris, including:

  • Actual danger
  • Timing
  • Traffic conditions
  • Car capabilities
  • Driving skill
  • Driver awareness
  • Occupants
  • Pedestrians
  • Weather conditions
  • Roadway status
  • Etc.

According to a study that looked at debris related incidents in the United States during the time period of 2011 to 2014, there were an estimated 200,000 car crashes that were attributable to debris situations.

Of those 200,000 car crashes, there were about 39,000 people that were injured, and approximately 500 deaths.

It’s a staggering and sobering set of statistics.

Chain Reaction Can Worsen The Situation

A car that swerves can end-up hitting another car, which then hits another car, and so on.

The chain reaction that originates by the initial reaction to the debris can be the mainstay of how the car crashes arise.

It’s hard to say how many accidents could be avoided if the cars just drove through the debris and did not swerve or otherwise react. You could argue that maybe if we all agreed to always just drive straight through debris, we’d have lessened counts of car crashes that were debris related. It’s hard though to be the driver of a car and realize that maybe if you are willing to get injured that it can save the lives of others and so be willing to not swerve your car.

That’s a tough pill to swallow.

AI Autonomous Cars And Flying Debris Aspects

What does this have to do with AI self-driving driverless autonomous cars?

At the Cybernetic Self-Driving Car Institute, we are developing software to aid in the debris reaction of the AI systems.

That being said, some AI developers have said that they think an AI self-driving car should just ignore flying debris.

The logic is that for a Level 5 self-driving car, which is a car that can be driven by the automation entirely and needs no human driver, there isn’t a human driver that can get injured by flying debris so why worry about it. The viewpoint is that the AI can just keep driving forward and let the debris strike the car. This goes along with the aforementioned perspective that maybe we’d all be better off collectively if we didn’t react to roadway debris.

Those that argue to ignore flying debris would assert that the flying debris isn’t going to harm anything per se, and so just let it hit the car. Sure, it might crack the windshield, but so what, they say. This doesn’t account for circumstances though that involve flying debris that can penetrate the windshield and then strike the humans inside the car. Just because there isn’t a human driver doesn’t mean that there aren’t people inside the car.

We still need to consider how to protect the human occupants.

The counter-argument is that the number of instances of flying debris that actually gets into the car compartment is very low, and so rather than trying to avoid the flying debris, it’s safer overall to instruct all cars to just drive through it.

Flying Debris Is A Hard Problem

The flying debris problem is multi-faceted and not so easy to solve.

Is there a single piece of debris or are there multiple pieces of debris?

Does the debris appear to be harmful or relatively harmless?

What is the predicted path of the flying debris?

Is the flying debris being ricocheted off of other cars?

How are other cars reacting?

And so on.

The sensors of the AI self-driving car need to be detecting that the flying debris situations exists. Via the use of the cameras, radar, ultrasonic, LIDAR, and other sensors, the AI needs to interpret the incoming data and identify that there’s a debris situation arising. In many cases, the debris itself won’t be seen right away and instead the reaction of the other cars will be the clue that maybe debris is involved.

You might recall that in my story earlier that I had noticed other cars dodging and weaving in the mattress instance, prior to my then seeing the white floating objects.

During sensor fusion, the AI is trying to piece together the telltale clues, which can be difficult to do because maybe the cameras don’t yet see anything amiss, but perhaps the LIDAR has detected the flying debris.

Each of the sensors has its own limits and capabilities.

The AI needs to be crafting an action plan of what to do.

Stay in the same lane or switch lanes? Try to make a swerve or continue straight ahead? Apply the brakes? Add acceleration?

These are all considered and must be placed into a sequence that can be applied.

Time is crucial.

Human Occupants In Self-Driving Cars

We also need to consider the human occupants in the car.

Some say that the AI should just proceed to do whatever it needs to do and there’s no need to alert the human occupants. They are just along for the ride.

But, this seems rather shortsighted.

One could argue that the AI should warn the passengers that there is flying debris. It might give the human occupants a moment to prepare themselves for what might happen next, such as the swerving of the car and perhaps the impact by the debris.

Others say that this is just going to scare the human occupants and since they aren’t able to drive the car then it doesn’t matter that they know in-advance what’s going to happen. If anything, they might panic and tense up, perhaps getting further harmed or even needlessly harmed by the forewarning.

This takes us into the ethics aspects of AI self-driving cars.

Do we want our self-driving cars to drive and not inform the human occupants about what is happening?

What’s even tougher in this matter is whether to have the humans be able to advise or direct the AI of the self-driving car.

Suppose a human occupant yells out that there’s debris and tells the AI to swerve to the left. Meanwhile, let’s imagine that the AI has detected the debris and wants to drive straight through it.

Should the AI proceed as it has planned, or should it do what the human says to do?


The flying debris problem is considered by many of the auto makers and tech firms as a so-called edge problem of self-driving cars.

This means that it is not considered at the core of the self-driving car task. Little focus to-date is being put towards the flying debris issue.

Nonetheless, per driving stats, it is well-known that debris is an issue for cars on the roadway and we’ll need to ultimately figure out how to have AI self-driving cars that can properly take action in the face of debris, whether it’s on the roadway or flying, or both.

This also includes ensuring that there is appropriate interaction with the human occupants of the self-driving car.

They do indeed matter.

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Copyright © 2019 Dr. Lance B. Eliot

Dr. Lance B. Eliot is a renowned global expert on AI, Stanford Fellow at Stanford University, was a professor at USC, headed an AI Lab, top exec at a major VC.

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