Future of Transportation
On the outer fringes of the personal rapid transit system just described, the network of lines in the lower density areas, to remain economical, would probably be too far apart for convenient walking access, and unsuitable for short neighborhood or local trips. The new systems study found the dual mode vehicle system to offer a possible solution to these problems.
In a dual mode system, the vehicle can convert easily from travel on a street to travel on an automated network. It thus could serve as a logical extension or elaboration of personal rapid transit.
The dual mode vehicles could operate on the parts of the network of lines used by personal rapid transit. Vehicles would drive from the streets onto the guide way at selected PRT stations. Shown below is a small car entering the network through an inspection point, a destination encoder and an automated fare collector.
Dual mode personal vehicle systems would give the same service for persons who did not own or know how to drive an automobile as would the personal rapid transit system. They would use public vehicles on the automatic guide ways, and would walk or transfer to other systems for local trips. However, the guide ways also would be accessible to privately owned or leased vehicles which could be routed on and off ramps connecting with ordinary streets, and driven over the streets to the driver's destination just as in the case of an automobile. At the point of destination, the vehicles could be parked as they are today or, if they were leased for the trip, they could be turned in at local connection points for redistribution to other users. This last method has the advantage of minimizing parking problems in congested areas.
A dual mode system presents more technical development problems than the personal transit system. However, it should be possible to work on such problems simultaneously with the development of personal transit, and to so design personal transit systems for ultimate dual mode use. The earliest developmental problems will be in the adaptation of propulsion, suspension, and guidance systems for use on both automatic guide ways and regular streets. None of them seems insurmountable in the light of present knowledge.
Propulsion on the guide way, as in the case of the personal transit system, would almost certainly be electric, probably using third rail power distribution in prototypes. In the final development of the system, however, propulsion might be a version of the linear motor discussed previously. Vehicles would thus need an electric motor; off the guide way they would run on batteries or use a separate engine to generate power for the electric motor.
Since these are the directions in which propulsion technology for ordinary automobiles may evolve to achieve reductions in air pollution, the propulsion problems of a dual mode personal vehicle are likely to be solved well before its other problems.
The most difficult technical problems are those associated with the development of a control system. Two different courses are possible. One is to concentrate the burden of control in the automated guide way (using equipment like linear synchronous motors and wayside computers); the other is to concentrate it in the capsules. The cost and complexity of the guide ways would be reduced if the controls were in the capsule, but the controls could be damaged when the capsules were off the guide way and being driven by individuals, and there could be additional safety hazards. The personal rapid transit system described earlier could operate at less than 10 cents per passenger mile with 15,000 passengers per day; the dual mode system might cost as little as 7 to 8 cents per passenger mile, depending on whether the vehicles were privately or publicly owned.
If research and development of personal rapid transit and the dual mode system were undertaken in concert, the principal costs for guide ways, controls, and propulsion systems could be shared. The development, test, and evaluation of street vehicles which could also operate automatically on the guide ways could add $150 million to the previous $250 million estimate. While one first-generation form of the dual mode system could be demonstrated in less than 10 years at a cost of less than $35 million, the full-scale development, test, and evaluation of a compatible personal rapid transit and small dual mode vehicle system would be a more uncertain venture and could require a total of about 10 years and $400 million.
References:-
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4. Planes, Trains, and Automobiles (of the Future) Available from: URL http://www.good.is/post/planes-trains-and-automobiles-of-the-future/
