Self-driving cars face many unsolved problems. But contrary to popular belief, narrow roads are not a problem for self-driving cars. In fact, it’s a scenario in which the robot cars can far outperform humans

Editor’s Note: This article first appeared on Robocars.com

Jean-Louis Gassee, while a respected computer entrepreneur, wrote a critical post on robocars recently which matches a very common pattern of critical articles:

The pattern is as follows:

The author has been hearing about robocars for a while, and is interested

While out driving, or sometimes just while thinking, they encounter a situation which seems challenging

They can’t figure out what a robocar would do in that situation

They conclude that, thus, the technology is very far in the future

His scenario is the very narrow road, so narrow that it really should be one-way, but it isn’t. In most of the road, two cars can’t pass one another. Humans resolve this through various human dynamics, discussion and experience.

In most of these examples, the situation is not one that is new to robocar developers. They’ve been thinking about all the problems they might encounter in driving for over a decade in many cases. It’s extremely rare for a newcomer to come up with a scenario they have not thought of. In addition, developers are putting cars on the road, with over a million miles in Google‘s case, to find the situations that they didn’t think of just by thinking and driving themselves. It is not impossible for novices to come up with something new – in fact a fresh eye can often be very valuable – but the fresh eyes should check to see what prior thinking may exist.

Some of the problems are indeed hard, and developers have put them later on the roadmap. They will not release their cars to operate on roads where the unsolved situations may occur. If snow is hard, the first cars will be released in places where it does not snow, or they will not drive on their own if it’s snowing. In the meantime, the problems will be solved, in a priority order based on how often they happen and how important they are.

The “two cars meet” situation involves very rare roads in the USA, so it’s not a high priority problem there, but it would not be a surprise problem. That’s because current plans have cars only drive with a map of the road they are driving. No map, they don’t drive the road.

That means they know the road well, and exactly how wide it is at every spot, and what its rules are (one-way vs. two-way and so on.) They will know their own width and the width of oncoming vehicles accurately. If they can’t safely drive a road, they won’t drive it. If it’s a rare road, the cost of that will be accepted. Driving every road everywhere is a nice dream, but not necessary to have a highly useful product. While Google’s ideal prototype is planned to be released for urban situations without a wheel, cars that need to go places where they can’t drive will continue to offer wheels or other interfaces (joysticks, tablet apps) that let a human guide them to get through problems.

The two-cars meeting problem is interesting because it’s actually one where the cars can far outperform humans. It’s also one of the rare times that communication between cars turns out to be useful. (Typically car to server to server to car, not direct v2v, but that’s another matter.)