The way Google Maps estimates traffic is by assessing the density of phones that enable the app to access their location, confirmed a Google spokesperson. Therefore, to the app’s technology, the only explanation for Weckert’s 99 phones in a condensed space was a dense traffic jam. The spokesperson also said, somewhat creepily, that Weckert’s experiment helps Google figure out where its geolocation needs to improve. It can distinguish between the motions of a car and a motorcycle, apparently, but recognizing movement in a wagon is still beyond it.