This has already been explored by Google at 4 way stops. They concluded the car needed some aggressive patterns to match the human style at intersections, and programmed it in, and it worked. I would be very surprised at any call by the law to punish this. It might be strictly legal but hardly rational to enforce a situation where the vehicles would get delayed. Especially the people behind the "stuck" vehicle would be vociferous in complaining if the law forced this option.

However, in the meantime, the cars will have people in them, who can take the wheel and get through any situation the car can't handle. In the more distant future, if the cars are empty, they themselves are not in a hurry, but the people behind them might be. By that time I expect working data service at things like highway lane merges where a remote control center could resolve the issue.

The reality is that while one driver might say "hah-hah, I can cut off the robot and it will lose the game of chicken with me and back off because it's a stupid robot. Hah-hah." But they will really be saying it to all the humans waiting behind that robot, and while some people are jerks like this, everybody will not be, and the robot will find a way.

I doubt an umanned robot would be designed to truly force its way in, though it might be programmed to take its share of the contested right-of-way and back off if the other car insists harder. There are lots of drivers today on the roads who follow that pattern already.

I agree that jaywalkers and rule-ignoring cyclists are an interesting challenge. California gives the right of way to cars outside crosswalks (implied and marked) but requires due care to protect the jaywalker anyway. That doesn't mean the vehicle has to stop, but it might well slow down for a jaywalker -- as many humans do.

One example we've seen of robocar programming being adjusted to "the real world" is Google's discovery that they could not navigate busy 4 way stops if they always yielded to other drivers, even those going out of turn. They learned they had to assert themselves when it was their turn, even if somebody else was also trying to go out of turn. What normally happens is the other driver backs off. Sometimes the other driver does not back off, and then the robocar strategy is not to try to play chicken.

I have wondered what happens if human drivers start to exploit the fact that the robocars will always yield in a true game of chicken, even if the human driver does not have the legal right of way. They might well do that, but don't forget, the robocars will have passengers who are put out by this, and they might well do things like take the wheel and continue the game of chicken, or they might make note of the fact the car is making video of the whole situation, and with the other car entirely in the wrong, vehicle code wise, they might e-mail it to the police.

If the robocar is vacant it will not try to win a game of chicken, so that will slow it down, but it doesn't care, it's a robot. Eventually it will get an in.

There have indeed been attempts to make cars so they can't exceed the speed limit. There was indeed strong pushback against this or any laws requiring it. While machines may not have autonomy, humans do, and we insist on it, and we want our machines to obey their owners, not the government. The responsibility for obeying the law belongs to the humans giving commands to the machines.

Because European regs asked for speed limiters, they exist on a number of cars today but I do not believe they are widely used. Sometimes I believe people use them in giving cars to teens and so on.

The reality is that there is the posted speed limit on US highways, and the real speed limit, which is higher and not at any fixed point. Rather, you will almost never get a ticket under +5mph, very rarely under +10mph, and with gradually higher probability above that. This depends on the roads and what the road is actually capable of, and traffic, and the moods of police, and sometimes even the revenue desires of police.

In France, they have a different system. The limit on the Autoroute is 130kph. Almost people drive a bit below that limit, some a fair bit below. Police reportedly ticket anybody going over that limit if they see them. This is how it should work, it is called the rule of law rather than the rule of men.

You refer to a pretense that the speed limit is actually a limit. You are correct, that is a pretense. Pretenses are bad.

It is also worthy of note that the safe speed limit actually varies from driver to driver, car to car, road to road, weather condition to weather condition, traffic condition to traffic condition. It is not a single number. Human law insists it be a single number, but that's not the ideal choice when considering machines. In addition, the speed limit is not a cliff, where at 65mph you are safe and 66mph you are unsafe. There is a risk of accidents at all speeds. The speed at the time of impact does affect the damage of the accident of course, but again it is a gradual scale.

With robocars, you have the option to test the system in all sorts of conditions and roads and traffic and know the right speed choice equation for that particular vehicle in its particular situation. This is the best way to determine what speed the vehicle should go. However, instead we have a fixed number. We are not able to do that today, so they lay down a single number, and humans exercise their own moral judgement on what speed to go, and assume the risks if they exceed that number. Because of social convention, there is generally very low risk of punishment if one is going in the "middle of the pack" speed-wise on any given road.

There are multiple ways you could change that system if you don't like it. As noted, the US often takes the individualist view and leaves the decision up to the person in control. From a utilitarian viewpoint, the challenge is complex. If you make the machines enforce the law, and go much slower than other traffic, you get three consequences:

• The machines are moderately safer, possibly reducing their accident rate and severity. If they are programmed well, it reduces it from very, very low to very, very, very low.
• The machines are seen as impeding traffic, generating some resentment towards them. In some circumstances, if they travel well below the prevailing speed of traffic, they may actually increase the level of accidents caused by others.
• Because they cause longer travel times, they are less popular than they could be. There are fewer of them and more human driving, which increases the the frequency of accidents. Further, people "in a hurry" with such vehicles would disable the self-drive system and take the wheel (and throttle) under human control, increasing the frequency of accidents.

While it's hard to predict the exact result, it's entirely possible that making the vehicles go at the speed limit could cause more accidents, quite a few more than would be saved due to the lower speed. Perhaps in a future day with most cars being robocars, it might be practical to limit the speed and reduce severity, but practical still doesn't mean it's a good idea. However, in that future, the speed would be limited to a new robocar speed limit, not one calculated for human driving. The robots might well go 90-120mph on easy highways, the humans being the obstacles in the road.