Knowing the speed limit is a critical part of being a safe driver, but it's not always easy to know it. Some roads are poorly marked, and you certainly can't base it on how others are driving. Thankfully, Google has shown the speed limit in the Google Maps mobile app for a while now, but it has never migrated over to Android Auto in the car dashboard for most users. That appears to have recently started changing for many users.
The Google Maps mobile app has shown the speed limit for over a year. When using turn-by-turn navigation, you'll see a little speed limit icon in the bottom left corner. This is great, but it has never shown up in Google Maps for Android Auto. Obviously, that would be super useful as well. According to users on Reddit, it's finally present in the Android Auto screen.
The rollout of this feature appears to be very sporadic. Some report having seen it for months while others still don't see it. The rollout also appears to be happening in multiple countries as people in the US and the UK are reporting it. If you do have it in Google Maps on the Android Auto screen, it appears in the bottom left corner in a floating circle icon while using navigation.
Source: Reddit