Tipping rules for Auto delivery

[GruntyPants]

Hello all,
I'm about to receive my 'new' tow rig from California, and I wondered if there is an expectation of a gratuity for the driver, and if so how much? Would it be based on the total price charged to my by the company? Is it based on mileage? Has the same driver been in possession of my truck the duration of it's cross country journey?

All these questions must be answered for fear of committing some type of over-the-road-faux-pas.

I mean, Even if the truck gets here in good shape, I can't really be sure that I got good service from him, or can I? Will he provide documentation that he fought off evil marauders along the way to keep my vehicle safe? Did he put together a travel plan with a national team of meteorologists and highway-environmentalists to ensure that no acid rain, salt spray, gravel trucks, sea-gulls or hippies would tarnish or offend said vehicle?

So if anyone has had any past experience with auto transport services or is a driver themselves, I would appreciate any feedback.