a team led by University of Michigan computer scientist Alex Halderman has found that traffic signals and their controllers can be hijacked in minutes.
This needs to be qualified by a statement that they've taken over a particular system used in a particular location. As it's written it implies that what they've done can be used on any traffic signal site, anywhere in the world. There are many different traffic signal control systems used the world over. While they are all potentially just as insecure, the outcomes of this exercise are relevant only to the system that was tested.
Biting the hand that feeds IT
