I agree. I don't think the truck had anything to do with the murders. I think the truck is a red herring and is notable because I think it's unusual that it was used in a convoy that had a wanted quadruple murder suspect involved.
If it's not related, it is very interesting that with all the talk of who's a criminal and who consorts with criminals, whoever was driving the Amerit truck would be gainfully employed by a legitimate company. Mechanics are in high demand and are well-paid (in my experience). If we can believe this solid citizen was part of a convoy that included a quadruple torture-murderer, why is it so hard to believe a wanna-be race car driver could travel in the same circles?