[TkTech]

This doesn't matter at all to Google's cars. They are designed to ignore the speedlimit in favour of the real speed of traffic around it[1], as it has been proven to be far safer than slowing down. It's currently caped at 16km/h over but this is an arbitrary limit.

1: http://www.bbc.com/news/technology-28851996

[lttlrck]

It must matter when there are only Google cars present.

[pests]

That is actually a pretty interesting point you've made.

[mikeash]

Yeah, it's a good one to think about. I imagine massive swings in traffic speed with a frequency of a few minutes as the cars get into various interesting feedback loops.