I have used my personal vehicle first half of this year for work travel. Now I want to transition to keep my personal car for personal use and purchase another vehicle this year for 100% business use. Can I claim standard mileage rate for the personal vehicle use for first half of the year and also the standard 179 deduction for the new vehicle for second half in the same year?
are you an employe getting a w-2 or self-employed?
as an employee none of your vehicle expenses are deductible for federal purposes but some states may allow a deduction.
as self-employed - schedule C
yes you can use different method for the two vehicles with one caveat
if you used actual expenses for the first vehicle you cannot switch it to the standard milage method.
There are other complications if used in a business such as a partnership, S or C-corp where you own the vehicle rather than the business.