Traffic Mix and AI Autonomous Cars
By Lance Eliot, the AI Trends Insider
Car traffic can be downright exasperating, frustrating, beguiling, exhausting, and just a real pain in the keister (pardon my language).
Most of us dread getting stuck in traffic.
Endless sea of cars.
Stop and go movement.
Bumper to bumper with a chance of some scrapes and fender benders.
There are the looky-loos that aren’t paying attention to the driving task and instead are looking at billboards or watching cows out in the fields (well, for more out-of-the-way driving locales). There are the drivers that seem to think that if they get within an inch of your bumper, it will somehow make the traffic go faster. There are the knuckleheads that have their blinker on for miles at a time, apparently oblivious to the aspect that they are confusing other drivers and causing the rest of us to wonder if the dolt will suddenly change lanes without any actual viable notification.
Many of us bemoan that it’s not us that makes the traffic especially arduous, but instead those other drivers that seem out-of-touch or otherwise confused about how to properly drive in a traffic oriented situation.
Normally, if the traffic is flowing smoothly, there are less of these disruptive drivers or at least they seem less apparent. Once the traffic starts to get clogged, it becomes a real survival-of-the-fittest world. Cars will swing into and out of lanes to try and get a few feet ahead of other cars. Drivers will raise a finger at another driver that appears to cut them off or try to jam into the lane ahead of them. In some cases, things can escalate out-of-hand and produce road rage with at times deadly consequences.
For my article about road rage and AI self-driving cars, please see: https://aitrends.com/selfdrivingcars/road-rage-and-ai-self-driving-cars/
Traffic Is A Delicate Dance Of Cars And Car Driving
Generally, our existing laws and rules-of-the-road allow for human drivers to exercise a certain amount of discretion within loosely bounded legal rules.
When a car to my right suddenly jams into my lane, and fails to signal, and fails to wait until there’s a reasonable opening, and fails to clear my car by more than a fraction of an inch, you could say that they have violated the law by creating an unsafe driving situation. But, who’s going to give them a ticket or stop them from this kind of discretionary driving? Unless by a stroke of luck there’s a traffic cop there, this kind of driving behavior is going to be gotten away with, unfortunately.
Thus, the day-to-day traffic that we survive in can be characterized as not being uniform, and not necessarily enforceable as to the strict interpretation of the laws of driving, and overall allows for human judgement to be used to decide in what way someone will drive their car.
Obviously, if the wayward drivers go beyond the allowed norm, and bash into another car, or they ram into a fire hydrant, or do anything of an “extraordinary” nature that’s a demonstrative law breaker action, the odds are they’ll get caught. I’m here trying to point out that at a level of driving just below that kind of clear cut legal outlaw stage, there is a lot of discretion as to how we can drive our cars.
If the roadway is pretty wide open and there are lots of lanes to choose among, the probability of a wayward discretionary driver that wanders up toward the legal outlaw line and getting caught is relatively low, while once there is a significant amount of traffic the probability generally gets higher. Also, once there is a significant amount of traffic, we now have more cars to contend with, and thus if say only 10% of drivers are the outlaw types, when you have just 10 cars nearby that means there is only 1 driver of the wayward type, while if you have 50 cars then you have 5 that are entered into the mix. In essence, volume of traffic makes a difference.
With the volume of traffic, we also need to consider density.
Generally, the more volume and the higher the density of traffic, the more that the actions of one driver can impact the other cars and drivers.
I realize this is not always true, in the sense that if you have a crazy driver even in light traffic situations, they can readily decide to weave in and around the other few cars and purposely try to cause them to hit their brakes or make other escaping maneuvers. It seems though that more often than not, the lighter traffic tends to allow for wayward drivers to do their thing without having as much a disruptive influence.
We could say that this is perhaps due to the magnitude of coupling.
Cars that have lots of room around themselves to maneuver can be considered more loosely coupled to those other cars around them. When the space between cars is tightened, it tends to increase coupling. I am referring to a virtual kind of coupling, and not any kind of true physical connections. It’s as though we had virtual invisible elastic bands that are connecting the nearby cars, and so when there is plenty of room then the cars are remotely coupled, and when they are closer to each other they are more directly coupled.
In close quarters traffic, if you suddenly get in front of my car by switching lanes without warning, and you do so within feet of my front bumper, I am likely to touch on my brakes to give you some added room and try to ensure that I don’t ram into the back of your car. Meanwhile, the car behind me, which we’ll say is also in close quarters, they too now might need to touch on their brakes. And so on it goes. A cascading effort can occur. It’s like a bunch of dominos lined up.
If it wasn’t close quarters traffic, and I touched my brakes, the car behind me which let’s say in this circumstance is some distance behind me, might not need to touch on their brakes. Instead, via the natural flow of traffic, they might be able to come a little closer and then we are still moving along freely. When the density of the traffic increase, which usually is also associated with the volume of traffic, the coupling aspects tend to mean that whatever happens with one car can cascade into other cars. Again, think of dominoes, but if they are spread out then when one falls it doesn’t necessarily cause the other one to fall too.
There are times that I’ve been on the open highway and had a high density of traffic, even though the volume of traffic was low.
A clump of cars happened to all get close to each other, even though the highway had miles upon miles of open space ahead of and behind us. This clumping can occur on a momentary basis, after which the cars then disperse out into the available open space. Or, sometimes the clump can remain a clump. This can be frustrating if you are part of the clump and don’t want to be in it. You’ve perhaps had to slow down demonstrably to let the pack move ahead, or maybe you’ve sped up mightily to get way beyond the pack.
Some drivers don’t seem to recognize when they’ve gotten themselves into such a clump.
They are just keeping their noses down and staring at the car ahead of them. Several of these cars with the heads-down kind of driver can eventually can meet up. They become a clump, basically by default. Not one of them thinks to get out of the clump. Other cars come along, encounter the clump, and at times get stuck in the clump as well. It can be difficult to get around a clump and might take numerous adroit attempts to do so.
The driving leapfrog techniques often applies when there are clumps, see my article on leapfrogging and AI self-driving cars: https://aitrends.com/selfdrivingcars/leap-frog-driving-self-driving-cars/
AI Autonomous Cars And Traffic Mix
What does this discussion about traffic mix have to do with AI self-driving driverless autonomous cars?
At the Cybernetic Self-Driving Car Institute, we are developing AI systems for self-driving cars and have been studying extensively traffic mix and the nature of self-driving car driving techniques and approaches.
Some AI pundits claim that there’s no need to study traffic mix since the world will be a wondrous place once we have all self-driving cars on the roadways.
In this Utopia, the self-driving cars will all communicate with each other via V2V (vehicle-to-vehicle communication), and politely share the roads with each other. An AI self-driving car will convey to another one that it wants to please go ahead and get into the lane with that one, and the responding AI self-driving car will communicate that yes, please do. They will dance together in a coordinated and cooperative manner. Furthermore, with the use of V2I (vehicle-to-infrastructure communication), these AI self-driving cars will be informed by the roadway that there’s a bump in the road up ahead, and the AI self-driving cars will ready themselves to handle the bump.
This might someday be our future.
But, until then, the real truth of the matter is that we’re going to have a mixture of AI self-driving cars and human driven cars. I say this because right now in the United States alone we have about 200+ million conventional cars. Those conventional cars aren’t going to disappear overnight. Instead, it will be years upon years, more like decades, before we gradually see AI self-driving cars becoming widespread and overtaking the number of human driven cars. Eventually, it may be that there are no human-driven cars, or it could be that people will insist on still being able to drive a car.
AI pundits complain that if humans still insist on driving a car, it’s going to mess things up. In one sense, they might be right. Based on studying the nature of traffic mixes, we can simulate what the future might be like in terms of the mix of human driven cars and AI self-driving cars.
Let’s first start by thinking about proportions related to the mix:
- 1:N – this is one AI self-driving car that is in the midst of N human driven cars
- N:1 – this is N number of AI self-driving cars that are in the midst of one human driven car
- 10%:N – this is a ten percentage mix of AI self-driving cars in a volume of cars that includes N human driven cars
- 30%:70% — this is a circumstance wherein the volume of cars has 30% that are AI self-driving cars and has 70% that are human driven cars
I’ll be using this above nomenclature when referring to the various mixtures in traffic of AI self-driving car and human driven cars.
Let’s also agree that when I refer to a volume of traffic, it is with respect to a given circumstance.
I am also going to for now make the assumption that we have a relatively high density of traffic in these circumstances and the volume is relatively high too. I mention this for the same reasons that I had earlier stated that when the traffic is wide open, the nature of how the traffic intermixes is generally different than the circumstances when there is tighter coupling.
We also need to agree what we mean by an AI self-driving car.
Herein, I’m going to refer to an AI self-driving car as one that is at the Level 4 and Level 5, which are the levels at which the AI self-driving car is considered the driver of the car, and does not need a human driver, and can drive in whatever manner a human driver can drive. Levels less than 4 involve having a human driver available in the AI self-driving car, doing so in case the human driver needs to take over the driving task or is given the driving task from the AI.
It’s important to consider that these traffic mix simulations involve a Level 4 and Level 5 self-driving car. For simulations with less than a Level 4, you would need to also include aspects of the human driver that might take over the control of the self-driving car. This would definitely impact the nature of how the AI self-driving car is going to be reacting in the simulation since you’d need to account for the times when the human driver is driving the self-driving car versus the AI is driving the self-driving car.
Another factor to consider involves the sophistication of the AI self-driving car. Even once we get to the Level 4 and Level 5, there are going to be proficient AI self-driving cars at those levels and others that we could reasonably agree aren’t as proficient. Not all of the Level 4 and Level 5 rated AI self-driving cars will necessarily be at the same level of driving skills.
Over time, there will be ongoing and continued improvements in the driving skills of even the Level 4 and Level 5 self-driving cars.
See my article about the defensive driving tactics of AI self-driving cars: https://aitrends.com/selfdrivingcars/art-defensive-driving-key-self-driving-car-success/
Additional Factors To Be Considered
There are more factors to be considered too about the traffic mix situation.
One really vital question involves how will human drivers react to AI self-driving cars?
You might at first say that human drivers won’t react any differently to an AI self-driving car than they do to another human driven car.
Well, you’d be wrong.
Human drivers will definitely be reacting differently to AI self-driving cars than they do to human driven cars, at least for the foreseeable future.
We’ve already seen that when AI self-driving cars are among conventional human traffic, the human drivers tend to give the AI self-driving car wide berth. It’s as though the human drivers consider the AI self-driving car to be the equivalent of a novice teenager learning to drive. The human drivers are suspicious of the capabilities of the AI self-driving car. The human drivers are wary that the AI self-driving car might make an odd maneuver or do something untoward. Thus, human drivers opt to treat the AI self-driving car differently than a normal everyday human driven car.
You might object and say that the human drivers won’t even necessarily be aware that another car around them so happens to be an AI self-driving car.
Right now, the experimental AI self-driving cars on the roadway are at times rather obviously detected, since there are only certain brands of cars right now that are outfitted as self-driving cars. Also, noticeably absent is any driver in the driver’s seat. Plus, some of the self-driving cars today have a LIDAR device on the roof of the car, and some also have branding on the sides of the self-driving car to point out that they are self-driving cars.
It is also relatively easy to detect today’s self-driving cars by the manner in which they drive.
Most of them are driving very slowly and cautiously. They come to a full stop at stop signs. They go less than the speed limit in places that most human drivers exceed the speed limit. They timidly proceed when an intersection light goes green. I realize that some human drivers also drive this way, but I am just saying that when you combine the driving behavior of today’s AI self-driving cars with the other more physically apparent aspects, you can generally know when you are driving next to or near a self-driving car.
This is a crucial factor when creating a simulation.
Most of the traffic mix simulations assume that the human drivers will be unaware that they are driving with AI self-driving cars around them. The simulations also assume that the AI self-driving car will drive in the same manner that humans drive cars, such as speeding, cutting corners, and so on.
Or, worse still, the simulations assume that all drivers will all abide strictly by the rules of driving and be polite and respectful, regardless whether a human driver or an AI self-driving car. I think we can agree that human drivers don’t drive that way.
Therefore, a realistic traffic mix simulation needs to consider for now that:
- Human drivers will drive as human drivers do, exploiting their allowed latitude and being wayward
- AI self-driving cars for the foreseeable future will drive in a more limited novice manner and be hardly wayward at all
- Human drivers will drive differently upon detecting that an AI self-driving car is nearby and will re-actively drive because of the AI self-driving car being in their midst
Maybe, far in the future, human drivers will become accustomed to driving around AI self-driving cars and so they won’t think twice about it.
Likewise, perhaps in the future the AI self-driving cars will drive more akin to how humans drive, doing so with a bit of swagger.
Traffic Mix Proportions
Let’s now return to the traffic mix proportions.
An interesting research study seems to suggest that having even one AI self-driving car, equipped with V2V, could improve safety and save energy in traffic (a study at the University of Michigan, “Experimental Validation of Connected Automated Vehicle Design Among Human-Driven Vehicles,” partially funded by Mcity).
I applaud the researchers for their efforts.
Not only did they do simulated aspects, they also ran a series of experiments on public roadways with actual cars, including AI self-driving cars and human driven cars.
This is the kind of work needed to help advance the AI self-driving car emergence.
In the experiment, the researchers were exploring what happens in a chain of cars when there is a cascading impact or chain-reaction due to a car braking and then re-accelerating. They found that the self-driving car was able to more smoothly deal with the circumstance, braking with 60% less of the G-forces and improving energy efficiency by 19%. The humans involved in the driving experiment were acting as a typical human driver might, namely tending to brake hard when caught by surprise about the chain reaction and then having to do a more rapid re-acceleration too.
Part of the trick here in this experiment is the V2V aspects.
This is great, but it also is focused on the future of when we’ll actually have widespread V2V.
Until then, we’re going to have AI self-driving cars on the roadways that either lack V2V, or are outfitted with V2V but no other cars anywhere near them also have V2V.
Also, as stated in their research, they were focused on single lane types of driving, and more expansive studies are needed to look at a fuller mix of traffic including multi-lane situations.
In our simulations, using the aforementioned assumptions about driver behaviors, we’ve found that when you have the situation of 1:N, this tends to actually worsen the traffic situation.
When there is a sole AI self-driving car among many human driven cars, it’s the equivalent of having a novice teenage driver among many seasoned drivers. The novice driver tends to go slowly and react timidly, which then causes the seasoned drivers to become provoked and try to find ways around that driver. It’s like a stream of water that a rock has been tossed into. The rest of the stream tries to find ways to get around that car. This is something to keep in mind in these early days of the adoption of AI self-driving cars on our public roadways.
In a similar kind of result, there’s the N:1.
When you have essentially all AI self-driving cars and mix into it just one human driven car, it tends to disrupt the traffic. This is because the wily human driver tends to drive in a wayward fashion, while the AI self-driving cars are all trying to work cooperatively and in coordination with each other.
Now, I would suggest that we’re not going to see anytime soon an entire array of AI self-driving cars and one lone human driven car mixed together.
By the time that happens, I’m betting that the AI self-driving cars will have been better equipped and programmed to handle the wayward human drivers and so they will be adept enough to cope with the human driver in their midst. In essence, I’m suggesting that by the time there is only a lone human driver among lots of AI self-driving cars, we will likely have first had a more proportionate mix of AI self-driving cars and human driven cars, and when the last few holdout human drivers are around will we have the N:1 circumstance (they’ll have to pry the steering wheel from their cold hard hands, so to speak).
Let’s consider the 30%:70% as an example.
In this case, the simulation consists of a volume of cars in a high density situation that has 30% or about one-third that are AI self-driving cars, and the rest or 70% are human driven cars. What happens in this scenario? Under the same assumptions as earlier stated, the human drivers are now beginning to get used to the AI self-driving cars and adjusting their driving behavior accordingly. The traffic appears to sway toward the AI self-driving car mode of driving. It’s as though the human drivers are now among a sizable bunch of teenage novice drivers, and the seasoned drivers are giving into their way of driving.
We still see traffic waves occurring in this mix.
Until the proportion of AI self-driving cars gets high enough and reaches a threshold, the human driven cars are still generally operating as humans do. With enough of the AI self-driving cars and once they get sophisticated enough, they are able to contend with those disruptive drivers. The disruptive drivers eventually too figure out that the AI self-driving cars are wise to them. Up until that point, the human drivers figure they’ll pull the wool over the eyes of the AI self-driving cars and treat them like patsies that are readily exploitable.
Another aspect that we include in our simulations is the impact of other driving aspects such as the mix of having motorcyclists, pedestrians, bicyclists, and other traffic elements.
Some studies focus on freeway only traffic situations, which then cuts out pedestrians, bicyclists, and other city or street regular driving circumstances. Some AI pundits say that we should have freeways devoted solely to AI self-driving cars, or if that’s not feasible then at least have lanes dedicated to AI self-driving cars. The concept there is that we might be able to gain the advantages of the all-and-only AI self-driving cars by giving them their own place to drive. This though will require some potential hefty changes in our roadway infrastructure.
See my article about induced demand and AI self-driving cars: https://aitrends.com/selfdrivingcars/induced-demand-driven-by-ai-self-driving-cars/
Today’s traffic can be maddening.
Imagine in the future when you get stuck in bumper to bumper traffic and look at the car next to you and there’s no one driving the car.
Will you still be able to show your finger to that non-human self-driving car? Even if you can, will it make a difference?
In whatever manner this all plays out, I think we can assume that we’ll have a small proportion of AI self-driving cars at first, which will gradually grow over time. At each of these stages of evolution of our traffic mix, we’ll see somewhat different traffic patterns emerge.
This is crucial to keep in mind when planning how we’ll be dealing with the mixing together of human drivers and AI self-driving cars.
Will it be like oil and water?
Or, can we get it to be more like milk and cereal?
Copyright 2019 Dr. Lance Eliot
This content is originally posted on AI Trends.
[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:https://forbes.com/sites/lanceeliot/]