Researchers at the University of Michigan were able to commandeer roughly 100 lights in an unnamed Michigan town. Each intersection has a radio and controller and all the radios are capable of passing instructions to each other. Getting on the network did not require a password and the communications between radios and controllers were unencrypted. The researchers blame the standards body that sets the NTCIP, which stands for the National Transportation Communications for Intelligent Transportation System (ITS) Protocol is a joint standard set by the NEMA, the American Association of State Highway and Transportation Officials (AASHTO) and the Institute of Transportation Engineers.”]
Source: https://www.csoonline.com/article/2600647/how-a-hacker-could-cause-chaos-on-city-streets.html