section 179 is limited to net income from your business before the deduction so if you enter the asset before the income no 179 will be allowed and depreciation will revert to 5 year MACRS. under MACRS since the purchase occurred in the 4th qtr the midquarter convention applies so you would only get 5% of the business portion of the cost. the business use must be more than 50% otherwise no section 179 is allowed. you didn't specify what type of vehicle because different types have different rules as to maximum first year depreciation.
