To avoid traffic jams, the smartphone app Waze takes crowd-sourced traffic reports in account to provide users with faster routes.

When the freeway in L.A. is jammed, Waze might offer a user a route that takes them off the freeway and through the backroads of neighborhoods. Some folks don’t like that now they have more people driving down their street.

Many residents are complaining to the city, but others have an interesting idea of the residents in some neighborhoods have started making fake reports of congestion on their streets. This would make Waze route folks away from their neighborhood. While it seems that no residents are actually attempting this more than talking, Shir Yadid and Meital Ben-Sinai of the Technion-Israel Institute of Technology figured out how to make Waze think there was a traffic jam using thousands of faked Waze accounts running on emulators.

They would poison the data to protect the quiet of their streets.

Waze was purchased by Google and the traffic congestion markers on Google Maps comes from a similar thing - they measure the number of android phones moving through a route. Could you register multiple Google accounts and phones, then engineer them to give false reports of congestion where you want it? Could you offer congestion as a service to residents of neighborhoods so that only the locals know to travel these streets?

Its common knowledge that people occasionally follow automated directions to an absurd point - travelling onto closed roads, into ditches, etc. Humans are expected to believe their senses over the directions that come from a computer. If driverless cars become a real thing can we expect the robot drivers to blindly follow the directions they are given? Can we expect those directions to take into account crowd-sourced traffic reports? What power does this give to those who are willing to poison the data?

Where else might congestion reporting be useful? Given enough power could you route traffic as a weapon - jamming your pursuers? Could you lower the property value of a neighborhood you are interested in investing in? Could you give your enemies children asthma?

Relatedly, think about other crowdsourced data that gets layered over maps. Could multiple 311 noise complaints or crime reports be used to make a neighborhood unattractive to home buyers?