ReformedCharacter wrote:I agree with your comments but I lack your confidence in the resolution of common road problems without inter-vehicle communication. Using the example of the lane problem... My local lane is single track in parts, it has two legs at roughly 90 degrees and is 'blind' in that radar or lidar would be unable to see the approach of another vehicle on the other leg. To complicate matters there are also junctions on each leg and the end of one leg is a T-junction with traffic passing at perhaps 40mph. and there aren't just two vehicles because there are more arriving because it is 'rush hour'. One leg has limited capacity because it terminates in a T-junction... Gridlock! For which the solution is mutual co-operation which requires communication. And that is one of the easier problems.
As to deadlock resolution, which I admit I do not know much about (quick look on Wikipedia) does it not generally require an operating system which can unlock the deadlock, the operating system being a proxy for inter-vehicle communication in this case?
RC
Even with inter-vehicle communication, the same resolution issue arises. Specifically, which vehicle is the master? If a group of vehicles come into proximity such that they can communicate, you still have the problem of establishing a single coordinator from them. And there are plenty of ad-hoc network protocols that have been designed to deal with just such situations (nodes being added to a network without any being explicitly designated the master prior to being connected)
And the algorithms associated with that are not too dissimilar to how you'd resolve the traffic dead lock in the first place.
There are lots of different algorithms with different features, quirks, etc, but without some form of designated master from the off, all of them require some degree of participants willing to relent and relinquish to (an)other participant(s).
OK, I'd agree that's better to do in computer memory than by shuffling cars around on a road, but doing it in computer memory will only work if all participants are involved in the electronic negotiation.
Unfortunately, unless you completely ban all human drivers and mandate that all vehicles must use the same network communication, you're going to have participants in the traffic dead lock that will not be participants in the electronic dead lock resolution negotiation.
The key thing in dead lock resolution is that one (or more) or the participants has to relinquish. Whether through being told by an agreed arbitrator, or by 'algorithm'.
A noddy way of dead lock resolution without an arbitrator in computers is for each participant to voluntarily and unilaterally relinquish their 'lock', then wait a random time before attempting to regain the lock.
In traffic terms, the equivalent of relinquishing a 'lock' would be reversing along the road on which the dead lock has occurred, back to a point where the oncoming traffic would be able to pass. And then wait there for a random time.
Without an arbitrator, it's possible that an oncoming vehicle might do the same - reverse up to a point where two way traffic is possible, then wait before retrying to drive along the road.
With random waits either side, eventually one vehicle will make it through while the other one is waiting, thereby (eventually) resolving the dead lock allowing the other to pass.
In reality, a better algorithm is the moment that one vehicle sees the other relinquishing (reversing), it then takes the opportunity to move forwards.
Just like humans do when they meet each other on a single track road. As soon as one relinquishes and starts reversing, the other car doesn't normally then do the same! Usually on seeing an oncoming car start reversing, you'd gratefully make use of it and move forwards.
And it just needs to be the rule that if you encounter a car on a single track road reversing towards you, then you also need to reverse - whether human driven or autonomous.
In practise this is just the same as what people do... only a real ****head would see that the car in front of them is reversing on such a road, and act a complete ****k and stand their ground preventing them from reversing further. Most reasonable people would realise they are reversing for a reason, and do the same!
So the rules are not really any different from how humans deal with single track roads already.... the occasional idiots excepted who will both determinedly stand their ground, refuse to reverse, ensuring no-one gets anywhere.
This fairly simply algorithm is compatible with (largely is) how humans already drive on single track roads, easily understandable by humans, and doesn't require an inter-vehicle communication that all participants must be involved in. And it is based on quite simple rules that an autonomous vehicle would be easily able to implement as well.
So perfectly reasonable in a mix of human and autonomous vehicles without intervehicle communication.