I don't see why they can not make that work eventually, it's just that the cars were developed in California and not in Sweden/Finland, we will have to wait a bit longer over here.
Google cars only drive where their high resolution maps exist, and can be correlated with the world around the car in real time. When it snows, and the world around changes, they can't function. This is a problem they will probably deal with eventually, but right now its something that haven't even tried to address. They are trying to address the low hanging fruit first, which makes an enormous amount of sense.
Yes, I know how they work. They can obviously handle a fairly large amount of change or else they wouldn't be able to drive anywhere. The environment changes constantly. They have driven autonomously on public roads for
over 10 million miles now. Since they developed the cars in California they just haven't had to deal with snow during r&d before. Since it never snows in large parts of the world they don't have to wait and fix that before they can launch either. But I don't see why snow should be too hard for them, and certainly not a showstopper. (At least under conditions that human drivers can also handle safely).
I assure you it's something they have tried to adress by now and are working on as we speak. How far they have gotten is anyone's guess, since they have long since clammed up about details.
Actually I see now that they are officially testing in Michigan since over a year back and "Waymo has been doing cold-weather tests since 2012":
https://arstechnica.com/cars/2017/10/waymo-starts-testing-in-michigan-to-master-snow-and-ice/ so it's clearly something they are working on.
https://twitter.com/waymo/status/994091703379415042?lang=enAre you really going to use stunts performed on a highly controlled circuit as an example of their prowess in automated driving? Its really not that hard to do. 99% of the automated driving problem is achieving safe free range driving.
That was the point I was trying to make if it wasn't clear: the software has better control over the car than >99% of human drivers. They have the potential to handle an ice patch (for example) much better than a human driver. Tesla's auto-pilot is nice but they don't have the same capability for free range driving as you put it. But they no doubt have very good control of the cars.
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I don't want to talk about self driving cars in this thread though, since it's even more off topic than nuclear power and there are already treads about self driving cars elsewhere.
I do believe they will have an impact on how many EVs there are on the roads though, since it makes a sense for Waymo to choose electric, and I expect they will expand quickly. They will definitely be operating in several cities in ten years from now. That seems relevant to the question of when electric cars will become mainstream.