Your browser doesn't understand Object elements

Advanced Transit Policy for the Seattle region       


What Is PRT?

Taxi2000-Bob Brodbeck

Personal Rapid Transit is a mass transit technology which will change the way you regard public transit. The simplest description of PRT is:

  • PRT uses a slender, elevated rail
  • A large fleet of small vehicles travels on the elevated rail
  • A city will have many small PRT stations, close together, in all neighborhoods
  • PRT does not use schedules, service is demand-responsive
  • A journey on PRT will take you nonstop between any two stations in the network
  • Like monorail, PRT is an elevated rail system which glides above traffic congestion. But from here the similarity ends.

    On-Demand. PRT is derived first by adopting demand-responsive service. By operating on-demand 24/7, PRT does away with transit timetables, one of the chief reasons most people don't find transit to be convenient. People will be more likely to use PRT than traditional transit if they know they can count on it being available any time of the day or night, with no waiting.
          A host of benefits flow from on-demand service, making PRT superior to all other existing forms of transit.

    Small Vehicles. What happens when we do away with schedules? Data on automobile usage shows that when people travel at times of their own choosing, 94-95% of the time they do so in groups of 3 people or less. It is most natural for people to travel singly or in small groups-- this is why buses and trains make riders gather in large groups in the first place. Therefore the best size for a PRT vehicle is very small, only 3-4 seats. People will be more likely to use PRT than traditional transit if they know they won't be delayed by having to wait for others.

    Non-Stop Travel. Since PRT serves individuals or small groups traveling to the same place, each vehicle can go straight to its destination without stopping along the way. In an urban location such as Seattle, PRT would travel at 35 mph. This may not sound fast, but imagine how far you could drive at that speed if you never had to stop for lights or traffic jams. That is how fast you could travel on PRT. People will be more likely to use PRT than traditional transit because it's faster and doesn't require transfers.

    Lighter Weight. Small PRT vehicles weigh only 1,000 - 1,500 pounds. Therefore the elevated rail can be very small and light too-- unlike multi-ton trains which require huge, reinforced structures or railbeds.

    Low Cost. The smaller and lighter PRT guideway is therefore less expensive per mile to build, in terms of the amount of materials needed to fabricate the parts, and in the amount of materials, labor and equipment needed for installation.

    Wide Coverage. By achieving low cost per mile, it becomes affordable to build enough guideway to reach all parts of a city the size of Seattle.

    Small Stations. Because large numbers of people don't need to show up at the same time to ride PRT, large stations aren't needed. Each station only needs an area comparable to the elevator lobby of a building. This varies according to the number of berths a station has, so in a residential area a station would need only 1 berth, and would be very small indeed.

    Convenient Access. Small size makes it affordable to build a large number of PRT stations-- so affordable that 3 or 4 can be built for every square mile. A station would almost always be within easy walking distance of every origin and destination within the service area. In Seattle, which is about 85 square miles, there would be about 300 PRT stations. Such easy access means people are more likely to use PRT than traditional transit.

    Better for neighborhoods. Small stations are easier to fit into neighborhoods without demolishing homes or businesses. Because there are 3-4 stations per square mile, the station near your house isn't going to be overrun with people driving from other parts of Seattle to access PRT, since their neighborhoods will have stations too. And your house, as well as your favorite corner store, won't necessarily have to make way for new station-area apartments and businesses. Low cost PRT can recoup its costs by serving existing neighborhoods. This means Smart Growth and upzone plans can be created according to what makes the most sense for urban growth patterns, not the needs of the transit system.

    High Capacity. On-demand service means it is practical for a comparatively small fleet of PRT vehicles to serve a huge number of people. Where trains serve a large number of people at few times, PRT serves a large number of people a few at a time, all the time.


    GetThereFast tries to keep up with Chrome and Firefox.
    Allow scripts in order to view dynamic content.