Simon Weckert created a virtual traffic jam in Berlin by pulling 99 used smartphones in a wagon: a large number of phones moving slowly looks like a traffic jam to Google Maps. “Through this activity, it is possible to turn a green street red which has an impact in the physical world by navigating cars on another route to avoid being stuck in traffic.”

Google’s statement to 9to5Google suggests that they’re taking Simon’s hack in stride: “Traffic data in Google Maps is refreshed continuously thanks to information from a variety of sources, including aggregated anonymized data from people who have location services turned on and contributions from the Google Maps community. We’ve launched the ability to distinguish between cars and motorcycles in several countries including India, Indonesia and Egypt, though we haven’t quite cracked traveling by wagon. We appreciate seeing creative uses of Google Maps like this as it helps us make maps work better over time.”

So people fed up with traffic being rerouted onto their residential streets could, conceivably, hack that traffic elsewhere—but not for much longer.