[kaybe]

I suspect they will rather limit the speed for autonomous vehicles since there's no limit, but above 130 km/h you will be partly guilty for accidents even if it wasn't your fault. (So it's a legal issue.)

The A9 is a very interesting choice because it links Munich to Berlin and probably has a lot of business travellers. If they could work while driving, it could be a big selling point.

[gambiting]

That's already the case with regular cars. There is no limit so in theory you could drive at 250km/h and it's perfectly legal(I've done it in the middle of the night, it's very cool if the conditions allow it), but if you get into an accident at anything above 130km/h you might be held liable for not driving at an appropriate speed.