Cabintaxi, a joint venture of Messerschmitt-Bolkow-Blohm (MBB) and Demag, has been the only group in the world to build a small-vehicle PRT system (referred to by some as a "true" PRT). A large test track facility was built in Hagen, Germany, that was used for an extensive testing program conducted from 1973 to 1979.
The Cabintaxi technology logged over 400,000 miles of vehicle testing and operations from 1975 to 1978. In 1977 the system completed fleet operation endurance testing of 7,500 continuous vehicle hours, and again in 1978, of 10,000 continuous vehicle hours, for a total of 17,500 vehicle hours of fleet endurance testing. The fleet was made up at its maximum in this time period, of 24 operating vehicles over two levels. The Cabintaxi endurance tests are the only fleet endurance test of this scale ever carried out successfully, including tests with vehicle separations under 3 seconds.