Hacked street lights?

There's probably an unglamorous reason that the LED street lights around this whole block are strobing in sync:-
First guess - failed power supply for the controller in "hiccup" mode (keeps failing to start).
Second guess - defective controller crashing repeatedly.
Third guess - Programming error or corrupted program.
But really - I kinda want it to be a test routine loaded into a networked controller remotely by a hacker.

#short