Brad Templeton, consultant to Google’s driverless division, has a post about autonomous-car parking, which comes in different grades of difficulty depending on where the vehicle is stowing itself. Communal rides like taxis and other rideshares will have the easiest time since their mission is largely driving, not parking. An excerpt:

The taxi doesn’t park
One of the simplest solutions to parking involves robotaxi service. Such vehicles don’t really park, at least not where they dropped you off. They drop you off and go to their next customer. If they don’t have another ride, they can deliberately go to a place where they know they can easily park to wait. They don’t need to tackle a parking space that’s challenging at all.

Simple non-crowded lots
Parking in basic parking lots — typical open ground lots that are not close to full — is a pretty easy problem. So easy in fact, that we’ve seen a number of demonstrations, ranging back to Junior 3 and Audi Piloted Parking. Cars in the showroom now will identify parking spots for you (and tell you if you fit.) They have done basic parallel parking (with you on the brakes) for several years, and are starting to now even do it with you out of the car (but watching from a distance.) At CES VW showed the special case of parking in your own garage or driveway, where you show the car where it’s going to go.

The early demos required empty parking lots with no pedestrians, and even no other moving cars, but today reasonably well-behaved other cars should not be a big problem. That’s the thing about non-crowded lots: People are not hunting or competing for spaces. The robocars actually would be very happy to seek out the large empty sections at the back of most parking lots because you aren’t going to be walking out that far, the car is going to come get you.

The biggest issue is the question of pedestrians who can appear out from behind a minivan. The answer to this is simply that vehicles that are parking can and do go slow, and slow automatically gives you a big safety boost. At parking lot speed, you really can stop very quickly if a pedestrian appears out of nowhere.

More crowded lots
The challenge of parking lots, in spite of the low speeds, is that they don’t have well defined rules of the road. People ignore the arrows on the ground. They pause and wait for cars to exit. In really crowded lots, cars follow people who are leaving at walking speed, hoping to get dibs on their spot. They wait, blocking traffic, for a spot they claim as theirs. People fight for spots and steal spots. People park badly and cross over the lines.

As far as I know, nobody has tried to solve this challenge, and so it remains unsolved.•