There may actually be a reason for the truck. Perhaps it is a simple as making the viewer ask "What's with the truck?" It did make you remember the image - whether you think it is directly related to the individual's business or not.
Years ago I had a very interesting woman come to me for the creation of her logo. She was a motivational speaker who used singing to convey her message to audiences. In discussing her identity project she clearly explained what she wanted/needed to convey to her target market - and then she added "Oh, and the logo needs to have a fish in it?"
I immediately asked, "Why a fish?"
She responded, "To make you ask that particular question."
She then told me that she would send me a video of her presentation and I would understand everything completely after viewing the tape. After getting and viewing the tape, I had the answer to "Why a fish?" It had EVERYTHING to do with her business, message and marketing strategy.
Often, when someone saw her logo, she would be asked "Why a fish?" With that question she then had them "hooked" into a discussion about her business, why they needed to hire her as a motivational speaker, and what kind of results she could offer. I'm not going to explain the reasoning in detail -- but it was a perfect addition to her logo on several levels when you knew her and understood the common message in her presentations. It gave people a bit of an "aha" moment when they "got it."
Admittedly, sometimes a truck is just a truck slapped up next to a name in an attempt to create what might be called a logo. In other situations the graphic element within a logo may be there to get the viewer to ask just the right question.
I also always recommend to clients that their logo not tell their target market EVERYTHING about their business - or there will be no questions to be asked by the potential customer.

