In general, anyone or anything in public view, whether on public or private property, with no expectation of privacy, with no expectation of photographs not being taken, is fair game when it comes to being photographed. Certainly, with all the security cameras in use today, no one can have a reasonable expectation of photographs not being taken of a truck stop parking lot.
Except in special circumstances (certain government facilities), there are no laws prohibiting the taking of photographs on public or private property. If you can be there, you can take pictures there - streets, malls, parking lots, office buildings. You do not need permission to do so, even on private property.
The logic, and the application of the law, is quite simple: If you can be there you can take photographs there, and even if you can't be there, but you can see there, you can photograph it.
Trespassing laws apply. If a property owner demands you leave, you must. But if a place is open to the public — a mall, office-building lobby, etc. — permission to enter is assumed (although it can be revoked). If on private property and the property owner tells you to stop taking photographs, you must comply with his wishes, even if he doesn't revoke permission for you to be there. If you are on private property, say, a truck stop, and are taking pictures of a truck on the lot and the truck owner tells you to stop taking photos of his truck, you are under no obligation to stop unless the owner of the truck stop tells you to stop. That would make you a Trucker Stalkerazzi. hehe
A property owner can prohibit you from taking pictures while on his property, but he cannot prohibit you from taking photographs of his property from a public place, as long as you don't take any "exceptional measures" to get the photograph (things such as extreme telephoto lenses, standing on a ladder to get above the hedge, etc.).
In terms of the law, trespass and photography are separate events; the former is illegal, but the latter is not. Only if the use of photographic equipment itself violates a person’s privacy (e.g., by using a long lens to look into someone’s private room) might it violate privacy law.
While people have a right of privacy, businesses do not except as it relates to trade secrets.
I picked up once at a Harley test facility at Talladaga and a guard casually mentioned the problems they have during race week with people coming over and taking photographs through the fence at the Harley facility. I just smiled, because I know that it's not against the law to take photographs in situations like that. Standing just outside the fence at the Harley facility puts you on property that is not owned by Harley Davidson, so whatever you can see from there you can photograph from there. Businesses that have an expectation to privacy as it relates to trade secrets are also obligated to protect and secure those trade secrets from public view.
Photographers can publish any photograph they take, with certain rare exceptions, regardless of whether the photograph was obtained legally or illegally. Whether you can take or publish a photograph is to be found amongst the various privacy laws, but the generally accepted and enforced "Four Prongs" of those should be followed.
Prong 1 (while gathering) - Unreasonable intrusion upon seclusion (trespass, unreasonable measures)
Prong 2 (if published): Unreasonable revelation of private facts (medical information)
Prong 3 (if published): Unreasonably placing another person in a false light before the public
Prong 4 (if published): Misappropriation of a person’s name or likeness
Violating any of the above 4 prongs and you are open to criminal and/or civil problems. You can even go as far as publishing a coffee table book of trucks you have photographed, and you don't have to obtain permission from a single truck owner to do it. However, if you place one of those pictures on the cover of the book, you'd better get permission for that one, cause it falls under a couple of the prongs related to trademark and copyright laws, as well as misappropriating the likeness of private property (the truck)as being an endorsement and willing participant in your book.
Probably the most important factor in taking and publishing pictures of trucks is just to use common sense. It's been touched upon, but it's probably the only thing that could get you into trouble here, and that is to not misrepresent the truck (or the driver or the owner) in a bad light by using a false or misleading caption or description, which would open you up to libel. Other than that, unless it's relevant to the story or the photograph, I think out of courtesy I'd obliterate truck and license plate numbers.
The only other one I'd be careful of is Prong 2 above, unreasonable revelation of private facts, and only then if you photograph a truck where you can see people inside the truck, as through the windows. I mean, I'd hate to photograph a truck where you can plainly see the husband a wife team in there, only to have it be a husband and girlfriend team, one of which is unknown to both the carrier and the spouse at home watching it all unfold on the computer.
