Google Maps traffic data is due to Google Maps tracking the MAC address and GPS coordinates of everyone using Google Maps. Google also knows the IP address of every business that talks to Google. If Google gives you an address, and you go to it, and you start showing that MAC address from that IP, google knows that business is that IP. They then know everyone else at that business. And yes. Google Street View was wardriving. But probably more because they could, than because they had to. I reckon they did it because they knew that whoever's databases they grabbed, they were inadequate for error-free navigation and the only way to reconcile them was to pound the pavement. Quora thinks Google spent $125-$700 a mile to do it. That means they spent between $700m and $2.8b on the US alone... the first time. They've spent about a billion dollars on self-driving cars. I'll bet if they hadn't spent that much the first time, they wouldn't have even tried self-driving cars.