Re: Not a problem solved
OK, I'll bite.
"The lights are out at the crossroads ahead. Does your car know how to negotiate the crossroads in a safe way which gives gives priority to other drivers according to the time they arrived and prevailing traffic? Can it establish basic signals to other drivers to indicate intent. Or does it just nudge out like an asshole and hope for the best? Or does it annoy the driver by giving up? How does it know to give up? Naturally it would have to do the right thing however many lanes, rights of way, trucks, buses, bicycles, motorbikes and cars (self drive and otherwise) there were."
How do WE do it? Usually by some established rules. First, keep the headlights on so other cars can see you. Second, don't assume you can go straight through. Third, FIFO. Fourth, if two cars arrive at once, use a left-hand first rule (use right-hand in right-side driving countries). Fifth, if all cars arrive at an intersection at once, wait a random number of seconds (between 1 and 10, including fractions) to see if one car moves. If not, creep forward yourself. Eventually, all cars acknowledge who moves first and use the left-hand rule to resolve the rest.
"A man is standing in the road by the traffic lights. A police man. How does your car know to obey his signals instead of the traffic lights?"
By recognizing the person in the middle of the street using forward sensors (technology already exists). Perhaps noting the badge or makeup of his/her uniform one can identify as a traffic officer or the officer can wear special indicative gloves (fluorescent, for example) that automated cars can easily see (would not be difficult to alter uniforms to accommodate self-driving cars). A little training and the car can recognize the hand gestures in 3D and know how to respond to them.
"A man is standing in the road by the traffic lights directing traffic. This man is a loony. How does your car know NOT to obey his signals instead of the lights?"
The same way we would, by noting the loony is not in uniform or using the special gloves and so on. And if he goes as far as to doll up as an officer, well that's impersonating an officer of the law, which is (a) a crime in and of itself and (b) capable of fooling a human, too, making the exercise moot.
"A big truck ahead is stopped and a guy hops out to halt traffic each way so the truck can reverse into some entrance. How far away does your car stop from this? How does it know not to try and overtake this obstacle?"
The car should note a pedestrian in the roadway and start assessing the situation. Consider how the situation is done today with humans. Usually, the pedestrian has to convey the situation to drivers, and the best way is to indicate a roadblock, either by standing in the middle of the road or (if the road is wide) by using road cones he brought with him. A self-driving car would already be trained to be aware of pedestrians and cones in the road and recognize them as obstacles. If the car can assess all paths are blocked, it should correctly come to a stop.
"Your car encounters a stationary bus in your lane. Is the bus broken down? Is the bus stopped at a bus stop or stopped at lights? If it's stopped at a bus stop how long is it likely to be there picking up passengers? When if ever is it safe to pull into the oncoming lane to overtake this obstacle?"
The car looks around. If the road is two-way two-lane, it has no choice but to wait. If there is an overtaking lane, are pedestrians approaching it? Is it near an intersection where it would need to be aware of the signal lights anyway? Those are things it can be trained to detect. If the way is clear, divert to the overtaking lane if open and pass the bus like humans do.
"The road has a big pot hole in it. Can your car see this? Can it see it when it's filled with water? Or does it just smash straight through it?"
Quite easily thanks to more advanced radar. And it should be able to distinguish water from a solid surface (it would register a different return pattern). Either way, the car should recognize to steer around it.
"A road is closed and there is a diversion in place. Does your car follow the signs or just keep driving until it falls into a hole the council just dug?"
Make the signs machine-readable by editing highway and traffic codes. Then the cars can read the signs and know what to do.
"You're going up a country lane. 50m ahead you see an oncoming car. Does your car know it has to pull into the verge NOW because there is no verge ahead?"
The car can (a) know about the no verge through its location and/or (b) look ahead and realize there is no verge, unless your vision is blocked, in which case how would WE know there's no verge ahead if we're not familiar with the area (which is (a) for the machine)?
"Your car goes into place with terrible radio coverage, or no GPS like a tunnel, underground carpark or simply a built up area. What does it do? Dead reckoning? Revert to the driver? What?"
How does a submarine know where it's going when it's underwater and radio-blind in the middle of a featureless sea? The tried-and-tested method is to use a three-dimensional accelerometer set to get a reasonable fix of location until a new fix can be made.