 So what happens if a traffic light gets hacked? Well, one researcher was actually able to do it. You can imagine how hacked traffic lights would be problematic. Even when traffic signals are broken or mistimed without being hacked, the problems compound for casual drivers, commuters, and CDL holders alike. But a researcher at a cybersecurity firm, Red Threat, published some blogs saying some of the devices used in civil infrastructure that manage traffic lights are not all that immune from being digitally hijacked.