He mailed the engineering board, the licensing authority, NOT the people in charge of traffic lights or having anything to do with them. Either he was trying to get fined by claiming to be an engineer or he's a fucking moron.
Some states have very strict licensing laws with regard to the term engineer, other restrict that to the term professional engineer. Nevada blocked Novell "engineers" from claiming they are such. The law on this is pretty settled, the guy is going to be lucky to pay that fine, by claiming he was an engineer directly to the licensing board he opened himself to the boards authority and they have the authority to incarcerate engineers under their authority and they can levy some pretty hefty fines.
I still can't figure out why he mailed anything to the engineering board. They have nothing at all to do with traffic lights, their sole purpose is engineering licensing. He mailed them a letter claiming to be an engineer. He might as well have mailed the bar claiming to be a lawyer or the medical licensing board claiming to be a medical doctor. That's how stupid what he did was.