Driverless cars might follow the rules of the road, but what about the language of driving?

Recently, while on my way to the University of Pittsburgh’s campus, I made a quick “Pittsburgh left” – taking a left turn just as the light turns green – while facing a driverless car.

Instead of jolting forward or honking – as some human drivers would be tempted to do – the car allowed me to go. In this case, the interaction was pleasant. (How polite of the car to let me cut it off!)

But as a sociolinguist who studies human-computer interaction, I started thinking about how self-driving cars will communicate with the human drivers they encounter on the road. Driving can involve a range of social signals and unspoken rules, some of which vary by country – even by region or city. How will driverless cars be able to navigate this complexity? Can they ever be programmed to do so?

What driverless cars can do

Here in Pittsburgh, Uber has tested self-driving cars with a backup driver behind the wheel; in Phoenix, Waymo’s cars operate in a limited part of the city without any backup driver at all.

We know the driverless cars are equipped with a technology called LIDAR, which creates a 360-degree image of the car’s surroundings. Image sensors can interpret signs, lights and lane markings. A separate radar detects objects, while a computer incorporates all of this information along with mapping data to guide the car.

Although ideally autonomous vehicles will be able to “talk” to one another in order to allow smoother navigation and reduce crashes, this technology is still in the early stages.

But any autonomous vehicle will also need to be able to interact with traditional cars and their drivers, as well as pedestrians, bikes and unforeseen events like lane closures, disabled stop lights, emergency vehicles and accidents.