TDY mileage increase for POV travel starts today Published April 17, 2012 By Finance Office 315th Airlift Wing JOINT BASE CHARLESTON, S.C. -- The Per Diem, Travel and Transportation Allowance Committee; effective April 17, 2012, TDY privately owned vehicle mileage rates are increased to 55.5 cents per mile. The old rate was 51 cents per mile. These changes are scheduled to appear in JFTR change 306, and JTR change 560, dated 1 June 2012.