Actually, most map data _doesn&#x27;t_ have speed limit data associated with it: <a href="http:&#x2F;&#x2F;opendata.stackexchange.com&#x2F;questions&#x2F;675&#x2F;data-source-for-speed-limits" rel="nofollow">http:&#x2F;&#x2F;opendata.stackexchange.com&#x2F;questions&#x2F;675&#x2F;data-source-...</a><p>Tesla is most likely using their machine vision system to identify speed limit signs, and then incorporate this data into their mapping data.