PRT Consulting, Inc.
1340 Deerpath Trail, Suite 200
Franktown, CO 80116, USA

Efficient Transit Solutions
How Personal Rapid Transit Works

How Personal Rapid Transit Works

This page describes the fundamental workings of PRT systems and only briefly addresses the many variations that can be found.

Fundamental aspects of a PRT system

  • Small driverless vehicles
    • Capacities typically range from two to six passengers
    • Vehicles are electrically propelled and may obtain power from on-board batteries or wayside "third rails"
    • Vehicles can be rubber-tired, steering themselves, hard-wheeled, riding on rails, or suspended from a bogey traveling in an overhead guideway
    • Vehicles typically meet regulatory requirements for accommodating disabled passengers
  • Exclusive guideways
    • Keep vehicles separated from other traffic and pedestrians
    • Have no crossings - only merges and diverges
    • Can be elevated, at- or below-grade
    • Guideways can be two-way but, unless demand is very high, layouts comprising linked one-way loops can be more efficient
  • Stations
    • Are offline on sidings
      • This facilitates nonstop travel
      • Adding stations does not slow through traffic
    • Numerous small stations are typically deployed
      • This facilitates short walking distances
    • Station berths can be in line with each other or offline from each other
    • Platform floors are typically level with vehicle floors facilitating roll-on, roll-off of wheelchairs and luggage
Personal Rapid Transit Check In Station
  • Switching
    • Switching is in the vehicles - each vehicle decides independently whether it is going left or right at the next diverge point (fork)
    • There are no moving parts on the guideway
    • This enables low headways (down to about one second between vehicles) and thus, high capacities (up to about 20,000 passengers per hour per direction)
  • Control System
    • Ensures vehicles operate safely and do not collide with each other
    • Pre-positions waiting vehicles where they are likely to be needed next
    • Responds to passenger trip requests by
      • Quickly sending a vehicle if one is not already waiting
      • Taking the passenger(s) along the best route from their origin to destination station
    • Monitors vehicle health (including battery charge)
    • Facilitates audio-visual communications between passengers and controllers

PRT system operations (from the passenger point-of-view)

Unlike conventional transit, PRT passengers have no need to know what the schedule is, what line to catch or transfers to make. All they need know is the name of their destination station.

In a simple PRT system, the passenger arrives at their origin station and purchases a ticket giving them access to the platform. They then approach the first empty vehicle bay and enter their destination station at the adjacent kiosk. The doors open on the waiting vehicle (or on the vehicle that arrives shortly), they board and depart for a nonstop trip to their destination station. This is a simplified operation that does not accommodate a tiered fare structure and does not encourage ride sharing, features which can make a PRT system more efficient and more attractive to a more diverse set of passengers.

A more complex, higher-capacity PRT system may cater to premium and economy passengers. A premium passenger would pay per vehicle - obtaining the exclusive use of a vehicle for themselves and other members of their party traveling to the same destination. Their waiting time would be minimized (probably less than one minute) and their trip would be nonstop.

An economy passenger would pay for their own trip and be expected to share a ride and wait (up to about five minutes) for fellow passengers to arrive. Fellow passengers would have the same destination or may be destined for a stop along the way. Thus, an economy passenger may have up to two intermediate stops. Facilitating ride sharing requires some organization of passengers in the station.

Personal Rapid Transit Station Animation . This two-minute clip shows how a four-berth personal rapid station facilitating ride sharing could operate.

Personal Rapid Transit Control Room in Heathrow