[sharemywin]

How do 2 cars cruise 60 mph through a 4 way stop without talking with each other.

[quasse]

That's a bit different from talking to "the cloud" as the parent poster was talking about. Cars will be using a short range radio technology like DSRC (5.9ghz band) to communicate locally. The FCC and DOT are already pushing mandates to have cars equipped with it.

[Animats]

Nobody is seriously trying to do that in a production vehicle. That would apply only to a highway system with all cars automated. Like this.[1]

[1] https://www.youtube.com/watch?v=zm_rlLyelQo

[sbierwagen]

https://en.wikipedia.org/wiki/Vehicle-to-vehicle

Talking to other cars is different from communicating over the internet.