Recently, a CPA lost his own business automobile deduction case in the U.S. Tax Court. The CPA had deducted business automobile expenses based on calculations from an after the fact MapQuest and not a contemporaneous diary or log. Tax court determined in this case that MapQuest did not provide adequate records for the purpose of a business automobile deduction.

Vehicles are used for business purposes. A business purpose can entail a client visit, delivery of goods, a sales trip or work training.