As Zbang states, most grounding is actually bonding. The title of Art 250 is Grounding and Bonding.
Not sure what a 332 cabinet is. I used to write articles for the International Municipal Signal Association and instructed classes for them. One class in Denver at the National Conference, I had an electrician from New York City (some 10,000 signals). based on what he learned in the class, New York made a change in how they grounded and bonded their signals.
At the service (Edison) the neutral is connected to the grounding electrode system by the Main Bonding Jumper. The EGC (grounds) all tie to this point which is to provide a path back the transformer, to clear a line to pole (case fault) and the fault current does not go to ground.
From your signal cabinet, there will be a EGC complying with 250.118 (please review this section) to the heads, poles and displays. The signals I worked on were almost all mast arms, so the poles were bonded to the EGC, and the heads, were screwed or clamped onto the arms.
What's different about traffic signals (pretty sure this is the same nation wide) is none of the equipment past the service is listed. Its just the way the signal industry does it, and every state and jurisdiction have there own standards, some reference the NEC, some don't. Our AHJs inspect the service and the agency has a label in the cabinet that states the agency acts as the certifying authority....This keeps the AHJs happy
So just make sure you have the ground fault return path per 250.118. If there are ground rods at the signal poles, thats ok, as long as they are not the return path for a fault, the ground rods are to be bonded to the EGC.
And as ZBang mentioned, lots of good videos from Mike Holt on grounding and bonding.
