Personal Rapid Transit in New Zealand - Future Transit Now

In this paper, Dr Ed Anderson gives a complete and concise view of the rationale of PRT, its history, current status, and potential. This is a robust technical explanation complete with the data and arguments needed to help planners and engineers get a full understanding.

Notwithstanding growing recognition that PRT is technologically feasible, a persistent question remains about its capacity to carry the necessary passenger loads.

The obvious importance of capacity to transit planning requires that the capacity capabilities of PRT be illuminated.

While the Advanced Transit Association (ATRA) does not sponsor any particular form of advanced transit, its members recognize the critical need for communities to have better options than now exist for meeting mobility needs in far-flung, traffic-congested, and increasingly environmentally sensitive metropolitan areas.

Fundamental to the design and planning of PRT systems is knowledge of the practical throughput of the off-line stations.

The throughput has been studied by means of computer simulations and by means of simple analytical formulae.

While simulation is essential to quantify the flow in specific cases, a theoretical understanding of the factors that determine maximum station throughput is needed to try to determine the most effective ways to increase it.

High-capacity personal rapid transit (Hi-Cap PRT) is a concept that has been evolving for over 50 years.

Notwithstanding attempts to kill it, it has kept emerging because in optimum form it has the potential for contributing significantly to the solution of fundamental problems of modern society including congestion, global warming, dependence on a dwindling supply of cheap oil, and most recently terrorism.

The future of Hi-Cap PRT depends on careful design starting with carefully thought-through criteria for the design of the new system and of its major elements.

The problem of precise longitudinal control of vehicles so that they follow predetermined time-varying speeds and positions has been solved. To control vehicles to the required close headway of at least 0.5 sec, the control philosophy is different from but no less rigorous than that of railroad practice. The preferred control strategy is one that could be called an "asynchronous point follower." Such a strategy requires no clock synchronization, is flexible in all unusual conditions, permits the maximum possible throughput, requires a minimum of maneuvering and uses a minimum of software. Since wayside zone controllers have in their memory exactly the same maneuver equations as the on-board computers, accurate safety monitoring is practical. The paper discusses the functions of vehicle control; the control of station, merge, and diverge zones; and central control.