Would you bully a self-driving car?

Mild mannered autonomous vehicles are set to be bullied by their fellow road users.

Two cars hurtle towards each other at high speed, unless one changes course, they will collide head on. But, just in time, one car swerves to avoid the crash. 

That car is the chicken.

Chicken is a game where one player tries to predict what the other will do before deciding on their own actions. If the drivers get it wrong, the consequences are fatal.

But, if one of the cars had been a self-driving car, an autonomous vehicle (AV), it would have detected the danger long before any accident occurred. It would probably have reduced its speed, steered out of the way and avoided any possibility of a collision.

An AV is a chicken by design.

A good thing too, of course. There are car drivers who, while not not crazy enough to play lethal games, are willing to take the occasional risk - maybe they will jump a red light that has just changed, or break the speed limit. Some people drive aggressively assuming that other road users will give way rather than crash. And this mostly works. But when it doesn't, accidents occur. 

How will the AV chicken cope with this sort of behaviour?

If they are willing to take advantage of human motorists, aggressive drivers will certainly be happy to bully AVs. And even more sedate drivers might be tempted to be more pushy knowing that self-driving cars are always going to play nicely with the rest of the traffic.

This is one of the things that researchers at the London School of Economics have discovered in a survey of attitudes to the introduction of AVs. They would get bullied. Pull out in front of an AV and it will slow down and let you in, overtake and cut in on an AV and it will let you do that, too.

They will even get bullied by pedestrians.

Here's another chicken game: a pedestrian demonstrates his disdain for danger by running across a road in front of traffic, trusting that the cars will stop or swerve out of the way. 

Whereas in the first game both drivers are heading towards mutually assured destruction, pedestrians have much more to lose than the drivers who might hit them. 

The likely outcome depends on the location, of course. Try this on a major highway and the consequences could be dire but in a queue of slow-moving traffic in a city centre, you are much more likely to get away with it.

A paper by Adam Millard-Ball of the University of California, gives a game theory explanation of Chicken games and describes how pedestrian behavior would be affected by the introduction of self-driving cars. It comes down to the risks or rewards of each possible outcome for each of the players. In the case of a collision, the outcome for the pedestrian could be hospitalisation, or worse, but it is also bad for the driver, who may be prosecuted or have their insurance premiums increased among other inconveniences. However, for a self-driving car it would be even more dire. 

Who would buy a car that ran people over, what traffic authority would even allow them on the road. AVs will have to be designed to be extremely safe and thoroughly risk averse.

An AV will have to be programmed to avoid pedestrians by braking or steering away from them. So the chances of death or injury to the pedestrian are minimised.

Consequently, pedestrians will be more comfortable playing chicken with the traffic.

In a trial in Milton Keynes, in the UK, small autonomous ‘pods’ have made short journeys at fairly low speeds in a pedestrianised area and successfully avoid walkers and cyclists. The video that accompanies the press release of this achievement includes a young man wandering into the path of one of the pods and cheerily waving as it stops to let him pass. Although apparently confident of his fate in a safe spot in Milton Keynes, he might think twice about stepping out into the M1 motorway, nearby, where the cars are traveling at 70 miles per hour - even if the cars were autonomous.

The upshot of all this is that, once other road users get used to the idea that AVs are meek and mild, they will take advantage of them. They will get cut up by other motorists and pedestrians will blithely wander across the road in front of them knowing that they will be safe. A journey in a self-driving car could become a series of starts and stops as it avoids the bullies. It will be slow.

Slow but safe. It’s very possible that drivers will be happy to accept slightly longer journey times in order to be able to take advantage of the benefits of not having to concentrate on the road. Reading the news or a book, using your mobile, texting, emailing, or simply relaxing and watching the world go by, could make your daily commute, or long-distance journey, more bearable. 

And maybe, eventually, the road bullies will learn good manners from their automated peers.

This mixed economy of automated and manually driven cars won't last forever, though. In certain areas, like the pedestrian part of Milton Keynes, the autonomous vehicle will be king. This could happen in, for example, city centres. Under these circumstances bullying by other cars won't be a problem and journeys should be quicker and smoother. And, if the vehicles have the ability to communicate with each other, they will be able to cooperate in the navigation of junctions, pulling in and out of traffic and so on. Whether these are personally owned vehicles or privately operated pods (as in Milton Keynes), it should help traffic flow and enhance safety even further.

LSE report on acceptance of Autonomous Vehicles, ThinkGoodMobility, 2016

Pedestrians, Autonomous Vehicles and Cities, Adam Millard-Ball, 2016


  1. My God. You talk about 'overtaking and cutting in'. A driverless car will leave a sensible gap AS SHOULD EVERY MOTORIST. Driving too close together is a human failing. It will, eventually, occur with driverless vehicles, but only because they are communicating with each other. By the way, what the fuck does 'self drive' mean? A self drive car is one you drive yourself. The new technology is driverless, not self-drive. Let's have some common sense on this.


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