Self-driving cars are no longer confined to controlled test tracks or even to placid suburban streets—they’re tackling real traffic in US cities such as New York, San Francisco, and Pittsburgh. They’re honing their skills amidst humans in Europe, South Korea, Singapore, and Japan. They’re preparing for the day they can purify our chaotic streets with their robotic perfection.

Learning how to drive in places like unruly Boston, a land of creative left turns and seemingly optional yields, comes with its challenges. But the aggressive driving and the complexity of the city’s twisting streets pale in comparison to the developing world. Even Patriots fans look like goody two-shoes compared to drivers who have little to zero respect for lanes, traffic signals, warning signs, and speed limits.

On wide roads without lanes and huge, anarchic intersections all over the world, human interaction dictates traffic flows, with each driver adjusting to others’ maneuvers on the spot, regardless of what the rule book says.

These informal systems work for the most part, but they come at a high cost. Of the 50 countries with the deadliest roads, 44 are in Africa or the Middle East, according to 2013 figures from the World Health Organization (the most recent data available). Together these nations accounted for nearly 250,000 deaths in 2013—a fifth of the world’s total.

Yet the factors that make these places the most likely to benefit from autonomous cars also make them the least likely to get the technology anytime soon.

"Many of the things that we're doing in self-driving at the moment probably wouldn't work if we were trying to do it in a third-world country," says Ram Vasudevan, codirector of the University of Michigan's Ford Center for Autonomous Vehicles.

Unstructured Driving

Autonomous driving requires understanding the intent and trajectory of everyone and everything on the road: vehicles, cyclists, pedestrians, construction workers, playing children, pets, an errant dart from a Nerf gun. In driving environments governed by a set of rules that people actually follow, the law limits the sorts of behaviors an autonomous vehicle should expect in the world around it.

The fewer formal rules in place, the more the ability to predict intent matters. Around wild humans, cars can’t rely on shared guidelines to dictate behavior. Basic driver assists that keep cars inside painted lanes, for example, are only useful if everyone else on the road respects lane markings. Otherwise they’re useless, or even dangerous.

Compared to suburban and even urban America, driving environments in many Middle Eastern and African countries have all the structure of a jellyfish. In Lebanon, where I live, it's common to see cars driving the wrong way, running red lights, and zigzagging across wide roads without the slightest regard to lane markings, among other shenanigans.

"There are no rules here. Everything is possible," said Daniel Asmar, a computer-vision expert and engineering professor at the American University of Beirut. "Humans can deal quite well with that, even if they get frustrated and honk at each other." For computers, the chaos would be an enormous challenge.

Even in relatively orderly environments, a confusing situation such as a freeway merge can make a self-driving car hesitate long enough to hold up traffic or even cause an accident, Vasudevan says. This might be because the car’s software, erring on the safe side, isn’t willing to merge in front of a speeding car, or because the car needed more time to understand the scene around it and the intent of other drivers. Put the same car on a road where stop signs, traffic signals, and yielding rules don't exist or are routinely ignored, and its reaction times will need to be a great deal sharper to survive.