American Express Car Rental Business Travel Account (CRBTA) A centrally-billed, cardless American Express Business Travel Account (BTA) specifically for use with the State's contracted commercial rental car agencies, Enterprise and Vanguard. The CRBTA is used to charge State traveler car-rental expenses to the traveler's department, saving time and State funds. Effective September 30, 2007, using a CRBTA and the American Express government card are the only authorized tools for renting cars from contracted vendors. Contact your travel program coordinator for approval to use the BTA.