[kriro]

Alternatively, they could also share their data in an open way and some device in regular cars could pick it up and use it to assist regular drivers.

I think both scenarios are possible. That data is valuable so maybe Google doesn't share it. Sharing it would create quite a bit of goodwill towards their cars so maybe they will. It's an interesting strategic decision. [not sure about data protection laws but maybe they can't share it even between Google cars unless the owners opt in]

[btiede]

Yes, I would be a HUGE advocate of them sharing this data. Autonomous cars can share their data with human drivers in the vicinity to alert them to situations on the road. Perhaps each vehicle (autonomous and human-driven) could contribute to an open network of data that any vehicle in the vicinity can access and process to alert their drivers or take necessary actions to protect the safety of all passengers.

Would be interested in hearing legal opinions about whether this data would only be shared if the individual car owners 'opt in' or if the operator - Google - could mandate the sharing of this data while the cars are on the road.

Trying to think of downsides to an open shared platform of such data.

[Piskvorrr]

Easy: a walled garden is much more valuable to its operator, and sharing the data would reduce (potential) profits. In other words, only Google can use the data it gets from its Waze, which gives it a competitive advantage.

Oh, you mean downsides to users? Never mind ;)