First, you have to be engaged as a business, paying taxes as a small business organization. That is a HUGE tax hit, trust me, I'm there.
If you are not a legitimate business, you might want to carefully consider this. If you are moonlighting without reporting income, you could be in trouble.
Wait a few months as the law will probably change allowing a FULL depriciation in the first year instead of the 3 year accelerated depriciation.
If you sell the vehicle, you will then pay capital gains on the vehicle depending on its FMV.
And you "loophole" haters out there, relax. The purpose is to relieve the capital losses incured by small businesses that typically over-utilize such a resource...a small business will typically see 75k miles per year on such a vehicle.
If I hear any complaints, remember, some of us SBO's pay 45% TAX on our receipts.