PRT is a 1960s invention, and it has never worked despite large research and development budgets. The only two working systems are so small and limited in scope that they cannot deliver the promises that make PRTs interesting.
- - The Morgantown PRT is a 5 station peoplemover with 20-person cars and obsolete space-age electonics. It has only few stations, the cars are everything but personal, and it is closed on Sundays and during holidays, as it only serves the local university and its remote campus.
- - ULTra in Heathrow is closer from the promise, but it only serves a parking lot and a single airport terminal. There are extension projects to reach other terminals and nearby hotels, but those are not currently planned or funded.