If you want real safety improvements, the vehicles need to be able to network and coordinate their movements to optimize the traffic flow and safety gaps. But that can't happen as long as bags-of-mostly-water are allowed to control vehicles. :)

I'm going to try to make a prediction here. I don't claim certainty. Maybe in ten years' time I'll fish it out and either shake my head or nod sagely.

The prediction is: for the general case, we are not going to get a self-driving car that's so reliable that you can stop paying attention. We might get it for special cases - motorways, some kind of special lanes, very slow speeds, things like that. Not for regular urban roads, not any time soon.

Much like so-called "artificial intelligence", current self-driving technology will improve a bit more, and then reach a plateau where further improvement will be very difficult, and it still doesn't work anywhere close to well enough. Getting past that point will require some kind of largely unpredictable major breakthrough, not incremental progress.

I'd still love to have a car that can self-drive on the motorway, though, and that might be feasible, especially with some kind of smart motorway infrastructure.

"I'd still love to have a car that can self-drive on the motorway, though, and that might be feasible, especially with some kind of smart motorway infrastructure."

I think this will be the winner because of all the self driving technology with obvious benefits this is it. I expect it makes sense for haulage to get the truck and goods over long distances with only local driving being needed and it would improve the driving experience for people travelling long distances. It could even increase the speeds on the motorway! Not that the law makers would do that.

The logical conclusion ends up as implementing really big trolley buses.

One disengagement per 8000 miles in a mixed environment seems quite good performance ... If disengagement simply means human had to take over rather than any accident.

While I agree that general AI suitable for all driving conditions is unattainable, a mixture of better sensors, better processors, improved training sets and specifically designed roads will, I think, bring a 'close to' general case for most roads, not just motorways within 10 years.

It's more a question of the time it takes for infrastructure to be renewed.

I drive around 1000 miles per month. From a technical point of view one disengagement per 8000 miles is fantastic but if I can effectively ignore my car for 8 months while it drives itself then it's very unlikely I'm going to be paying attention the one time in 8000 miles it needs me to do something.

This is the inherent problem with autonomous cars. Them becoming better means the driver pays them less attention which means when they do need attention they're less likely to get it. Autonomous cars are probably already good enough to fall into this awkward middle ground. Moving past it is going to take an awful lot of work. Any disengagements are probably too many and autonomous cars should concentrate on manoeuvering themselves automatically into a safe position if they're unsure of something rather than expecting a distracted driver to help them out.

But, but they had an exponential chart! Reliability will soon surpass infinity.

I'd like to be wrong, but I fear you are pretty much right. Expressway driving is pretty simple most of the time. Except when it isn't. So I think autonomous long distance trucking may be feasible. ... As long as the vehicles reliably pull over and wait for a human to help them out when they come to something -- snow, an accident, construction zone, whatever -- that they can't handle. Maybe a human can shepard them to the expressway on-ramp and to the terminal at the end of the trip? I have no idea whether the economics work. And the potential problems are legion. But just maybe that works. And if that works, you and I will likely be able to put our vehicles into autonomous mode on the expressway with some confidence that it'll wake us up when it needs help rather than assassinating us or innocent third parties.

But the notion that autonomous vehicles can safely drive urban, or suburban, or rural roads now or any time soon seems to me to be crazed. Too bad. I'd feel a lot safer sharing the road with well designed, reliable, autonomous vehicles. If only we knew how to build them.

from your correspondent Crash Likely.

The autonomous cars will presumably stick rigidly to speed limits

" The autonomous cars will presumably stick rigidly to speed limits "

There are reports that Teslas don't always. Sometimes at least they seem to 'keep up with the traffic' and in one case a Tesla accelerated into a crash barrier, hitting it at 70 MPH.

There are two factors that seldom get mentioned. One (and the most important) is that, in the absence of understanding autonomous systems can only be reactive to a limited range of stimuli, so there's inevitably an upper limit to improvement. The other is that testing has almost certainly been conducted in increasingly complex situations as the technologies have developed. Both factors make apparent progress increasingly hard.

However, overridingly, until cars can genuinely think, accumulate complex memories and draw intuitive judgements from them, the technologies will never reach the competence of the highly experienced and attentive driver. The best we'll probably achieve is replacement of the least attentive and most careless.

As an example of what I mean, I was driving one dark morning along a narrow unlit country road with a 50 MPH limit and many concealed tracks on both sides to plutocrat dwellings. Not far ahead off my near side, I briefly saw a moving red light partially concealed by trees. My brain said "fast car emerging suddenly into the road" so I braked. I was dead right - a low sports car shot into the road from an invisible track and turned across in front of me. If I hadn't braked we'd have collided. I'd be surprised if an autonomous system could work that out as the brief glimpse of the red light was about 45 degrees off my near side only lasted a second or so, and the offending car did emerged a few seconds later with no other indications of its presence in between.

"The last 10% of building anything takes 90% of the effort"

So far, the various autonomous vehicle initiatives have been able to pick off some relatively low-hanging fruit. Motorway driving, where vehicles are generally going at the same speed, lanes are clearly marked and rules are clearly defined. Supermarket car parks, where everything is slow moving and clearly marked. Etc.

But now, we're hitting the complex stuff. Town and city driving, where pedestrians and cyclists can - and do - behave irrationally or unsafely. Road layouts (at least in Europe) inherited from the romans and then mutated through centuries of gradual evolution and hasty modern hacks to deal with population growth and the mass adoption of motorised vehicles. And so on.

And dealing with all these scenarios is exponentially more difficult than what's already been solved. And they all need to be solved to the level where 99.99% of situations can be safely dealt with, because neither the public nor the various government car-safety departments will accept anything less...