Excellent point, stealing that. I work in automotive and an engineer, traveled around the world, think the realistic possibility of self driving cars without major changes in how we make roads, everywhere, is extremely low.
The only handwriting recognition system which ever worked correctly with a low error rate was Palm Graffiti. It forced the user to learn a new shorthand writing style designed specifically to avoid errors.
Because it asked users to learn a new way of writing, when the recognition failed, users were more likely to blame themselves, like, "Oh, I must have not done that Graffiti letter right, I'll try again."
But when it came to recognizing regular (i.e. natural) handwriting, users believed inherently (i.e. somewhat unconsciously) that they already knew how to write, and the machine was new, so mistakes were the machine's fault.
I think this supports the grandparent's point about using the actual strokes, including angle and azimuth, to reconstruct intent.
I was also fairly proficient with Graffiti, back in the day, but I consider that an input method, not handwriting recognition. I was facile with T9 as well.
There is little market demand for handwriting recognition, and thus little active research goes into it. Not because it is a difficult or problematic technology, but because better alternatives exist that make it irrelevant.
Even if someone were to come up with an absolutely perfect handwriting recognition system, most people wouldn't use it. Why? because the advent of multi-touch screens means that most people can type much faster than they can hand-write anyway.
What changed was that touch screens became better. The old capacitive touch screens were clunky, slow, inaccurate. You could put a keyboard on them, but the lag and poor accuracy meant you couldn't really touch type comfortably. Then multitouch came along and made on-screen keyboards much more responsive and accurate.
But also, Blackberry and (pre-smartphone) phones with SMS made people more comfortable with the idea of using keyboards for text entry on handheld devices. And crucially, auto-correct and predictive text entry covered up for accuracy errors and made text entry by keyboard even more attractive.
Why? It never exceeded consumer expectations, which are extremely high for automated systems. Even a correctness rate of 99.9% means multiple errors per day for most people. Consumers expected approximately zero errors, despite not being able to achieve that themselves, sometimes even with their own handwriting!
Because handwriting is made by humans, there is some percentage of it that simply cannot be reliably recognized at all. But people hold that against computers more than other people because computers are supposed to be labor saving devices.
Likewise because roads are made by people, and other cars are driven by people, so a self driving car will never be able to be perfectly safe. But that is essentially what advocates are promising.
That’s especially true if people expect the same level of convenience, especially in terms of time. People speed and take risks all the time when driving, in the name of saving time. I think it’s likely that an autonomous car optimized for safety would also be a car that just takes a lot longer to get anywhere with.
Speed matters. It’s a big reason we all use touch keyboards on our phones instead of handwriting recognition.