A No. When you convert a personal asset such as a car into a business asset, the depreciable basis equals the lesser of its fair-market value or its adjusted basis. Say that you bought the truck for $20,000 and added $5,000 in improvements to make it suitable for business use. If the truck is currently valued at $15,000, your depreciation deductions are based on the $15,000 figure, not $25,000.
Tip: Although the limits are slightly higher than the amounts allowed for luxury cars, tax law also caps the annual deduction allowed for vans and light-duty trucks. For 2006, the limit is $3,260, which you must reduce by the percentage of personal use.