Presumably, the idea behind these signs is to allow companies to keep tabs on their drivers by having other people on the road call in if they see them driving erratically.
(Can you imagine the opposite? Hi. I'd just like to say that the guy in truck #72 is a really good driver. He stays in the lines and signals before every turn.)
Here's the part that I don't get. Exactly WHEN are people supposed to make these calls? While they are driving? Or maybe later, when they are at home and might have completely forgotten the phone number, if not the entire incident?
Scenario #1: I'm driving along and notice a truck weaving in and out of lanes in front of me. I see the sign with the phone number, decide to make the call, and whammo - I get a ticket for using my phone while driving.
Scenario #2: I'm driving along and notice a truck weaving in and out of lanes in front of me. I see the sign with the phone number, decide to make the call later because I don't have a phone handy, start fumbling for a pen and paper to write down the number, and blammo - I get in an accident.
Both scenarios are possible if not entirely probable, and the only scenario that makes sense is if there's another passenger in your car who can either make the call for you or write down the phone number for later.
So I ask you, is it just me, or are these signs a waste of time?