Digging around in my Note 4 settings and discovered under location that the Google Play Services has access to my car speed? Really??? Why would Google need to know how fast I drive?? What if any functionality would I lose by force stopping the service? Is this specific to Samsung and the Note 4? Or a general setting for all Google users? Curious
How do you suppose you get the convenient "heads up" that your drive home from work is going to take longer than normal because traffic is backed up on the highway?
Answer: Google Maps uses Android users' "location data" (speed is a part of that data) to plot traffic flow. So yeah, you can disable it, but then what if everyone did the same? All of the Apple (iPhone) users would be lost or stuck in traffic lol
Access to your car's speed seems like a new permission added for Android Auto. The fact Google Play Services has that permission allows it to act as a common provider for this information to other apps (apart from using it for analytics).