An anonymous reader writes "Hackers can influence real-time traffic-flow-analysis systems to make people drive into traffic jams or to keep roads clear in areas where a lot of people use Google or Waze navigation systems, a German researcher demonstrated at BlackHat Europe. 'If, for example, an attacker drives a route and collects the data packets sent to Google, the hacker can replay them later with a modified cookie, platform key and time stamps, Jeske explained in his research paper (PDF). The attack can be intensified by sending several delayed transmissions with different cookies and platform keys, simulating multiple cars, Jeske added. An attacker does not have to drive a route to manipulate data, because Google also accepts data from phones without information from surrounding access points, thus enabling an attacker to influence traffic data worldwide, he added.' 'You don't need special equipment for this and you can manipulate traffic data worldwide,' Jeske said."