I purchased a new Full Size truck in November 2008. After purchase, I immediately started using it for business and personal use. I work for a car dealership, and I placed the Dealership name, phone #, my name, address on the sides of my truck with adhesive decals (non removable) Not Magnets!!

My question is can I deduct all of the mileage for my truck, since I am advertising for my place of work 100% of the time I am driving the truck?

Or do I have to deduct by miles or depreciation?