Personal Rapid Transit in New Zealand - Future Transit Now

In a synchronously controlled PRT system a vehicle waits at an origin station until the path through all merges to the destination is clear. The system then reserves this path for the specific vehicle in question, which then proceeds without any maneuvers directly to the destination. Such a scheme was proposed in the late 1960s for the automated transit system deployed in Morgantown, West Virginia. Because of its inflexibility in face of failure of any vehicle to maintain its path, interest declined, but the clear-path idea has emerged again on the Transit Alternatives mailing list on Internet. It is thus worthwhile to show why, by estimating the wait time for an origin-to-destination reservation, that fully synchronous systems are not practical except in very small networks.