He should. Insufficient evidence. Will the trucker be there? Can the trucker identify your friend's, er, face? Does the trucker have pics? This was have to be part of the evidenc. Your friend should take position the trucker was chasing him for some reason.
Or, maybe your friend should admit he was pissing into cup, and counter charge the trucker with invasion of privacy. Your friend wasn't intending for anyone to see him. Jeez, this is insane. Wonder if this trucker has done this before.
You have absolutely no idea what you're talking about.
That person wouldn't have been cited without some sort of evidence/statement, to begin with.
Many trucks now have cameras in them, recording 24/7...(my truck has two).
Trying to say the trucker had a beef with this fool ...impossible to prove & irrelevant. That statement will get tossed out immediately.
Also, it's not invasion of privacy. Supreme court has held that "eyes cannot trespass"...meaning it's perfectly legal to look into your vehicle, provided they are physically outside the vehicle at the time.
Get caught in a bullshit story in court....you'll wind up with a contempt charge, as well.
How about this: be a man. Show some integrity. Pay for your mistake. Learn from it & move on.