Rev. Rul. 55-637

The car mileage allowance received by a rural mail carrier for the maintenance of his automobile which is used in carrying on his employment as a rural mail carrier is includible in gross income for Federal income tax purposes. See I. T. 3541, C. B. 1942-1, 41. To the extent, however, that a mail carrier uses his automobile for his transportation in delivering the mail, he is entitled, in arriving at adjusted gross income, to deduct the cost of operation, repair, and upkeep, as well as depreciation. I. T. 3541, supra, amplified