They also remain fairly limited in their potential for commercial applications as well.

Vehicles that can drive themselves in certain circumstances do exist, and they have existed for quite some time. Some are on closed circuits. Some are very slow. Some are approved trials or being beta-tested by end users. Some only operate in public at night. Most are some combination of the above.

But what I've found odd about the topic is that we still don't seem to trust the idea of an aeroplane that can fly itself (and they do; some pilots and co-pilots have been reprimanded for going to sleep at the same time mid-flight instead of taking turns, and the autoland feature on various passenger aircraft - first used in the mid-1960s - is perfectly capable even if it isn't used very often), and yet investors (and the media in general) seem totally OK with the idea of a vehicle driving itself in uncontrolled conditions.

This, despite a significant number of crashes and fatalities involving so-called self-driving vehicles.

I say this because planes are flying in controlled conditions, by which I mean heavily-monitored conditions. If the weather is too dreadful, or there's some other reason it's too dangerous, they're not supposed to take flight or they are directed to land elsewhere.

Meanwhile, vehicles on public roads are a very long way from controlled conditions, with other road users of varying size, pace, vulnerability and competence, as well as pedestrians, animals and hazardous road conditions up to and including flooding with problems ranging from simple submersion to bridges or chunks of the road itself being washed away completely.

Even just regular suburbia on a good day is far more complex than a closed course for shuttling passengers or freight. Then there's the added complexity of reading road signs that aren't perfect because foliage hasn't been cut back in a while, something big is parked in the line of sight, or in rare cases, the sign has been tampered with in some way.

But what actually is an autonomous vehicle (AV) though? The Society of Automotive Engineers says that a vehicle can be classified from Level 0 which is no assistance for the driver, through to Level 5 which needs no driver at all.

Current Volvo global chief Jim Rowan disputes this however, because he says that if you still legally need your hands on the wheel that's not autonomous, it's ADAS (Advanced Driver Assist Systems).

Lawmakers also need to think of it in this binary way. In January 2022 for example, the law commissions for England and Wales, and Scotland, recommended a clear legal distinction be made between autonomy and higher levels of driver assistance.

They also recommended that the manufacturer should be held responsible whenever anything goes wrong with an AV, whether it's a simple traffic infringement or an epic tragedy.

One of their reasons was, and AV crash data seems to agree with them, is that a human can't be expected to take over at the last moment and avoid a catastrophe. Their attention wanes for one thing, plus the point of a true AV is there doesn't need to be a driver to begin with. It's also very challenging to successfully execute an emergency manoeuvre at the best of times, let alone when you have to commandeer control mid-emergency such as, to use one of their examples, dealing with a blown tyre.

And so, this distinction would take away the manufacturer's ability to pass off so-called self-driving accidents as user error, which would present them with a notable conundrum. Regardless of how much testing they need to pass in any country to prove the system safe, they should also consider their public liability well beyond what they already have to with regards to their involvement in a crash that necessitates a safety recall.