Truck Driver Institute (TDI) is an adult vocational school that trains individuals and couples to get their Commercial Drivers Licenses (CDL) and provides ongoing job placement with our more than 20+ carrier partners. Founded in 1973 by U.S. Army Veteran Thomas Gast, the school has grown to twelve campuses located in eight states. TDI is the largest Class A CDL School East of the Rockies not owned by a trucking company.