In this case, the the petitioner used his personal pickup truck to travel to his employer's customers. He recorded his odometer reading at the beginning and end of each month in his calendar book, but didn't record any personal travel that he made with his truck and didn't provide any other documentation related to his truck expenses. However, he claimed that he drove over 40,000 in business miles and claimed over $20,000 in vehicle expenses based on the standard mileage rate. The court upheld the disallowance of the deduction due to lack of substantiation. Garza v. Comr., T.C. Memo. 2014-121.