[UPDATE JUNE 7, 2017]
Is this feature not showing up for you? Confirmed by the Android Auto product team, currently the speed limit indicator will only work in two regions, San Francicso/Bay Area and Rio De Janerio. While they say other regions will be rolling out, no offical dates have been mentioned. With Apple’s iOS 11 adding lane guidance and speed limits in it’s upcoming release it might be a safe bet that we’ll see Google release and update soon however.
Your friendly neighborhood Android Police are reporting that after years of waiting Android users will now be able to see the speed limits when using Google Maps. While many OEM navigation systems and apps like Waze have had this feature for years, it is a welcome addition to the Android Auto experience.
It remains to be seen if Google Maps will eventually display your vehicle speed as well but seeing that Google owned Waze does this already, it is a good possibility we will see this in the near future.