Flexitaxi is a concept of tube tracing in a megalopolis for establishing operative and safe address deliveries of individual persons and small-portion consignments. The technological approach is described with reference to  four attributes.

First attribute: tracing and transportation

The system of tube tracing is not intended for collective carriage of the people and large consignments, but for organization of address, operative carriage of individual persons and small-portion consignments within a megalopolis. Besides it, purpose of this engineering problem is a complex removal of essential defects, which are inherent to the ground, underground and helicopter means of carriage of individual persons and small-part consignments from door- to-door. Therefore, to remove defects and to surpass such transit systems on many parameters, the tube tracing is specially established at sufficient height above the ground, that is higher than urban electrocommunication devices. This feature permits freely to provide stops, taking vehicle seats, setting down for individual passengers, unloading luggage and small-portion consignments, staying indoors, at built-in stations in megalopolis residential houses, business buildings, stations, airports, banks, hotels, police stations, schools and etc., and, the most main, to deliver passengers and consignments operatively and safely from door up to door.

A passenger, being in the street, can easily be elevated and be lowered by the outside lift on the stop places. He can also execute a passage to opposite side by a top way for changing a vehicle, or this maneuver can be automatically done on the way junction places.

Doing engineer tube tracing within the concept, turns round buildings and landscape structures can be done with the curvature of 95-100 degrees, in special cases even for corners of 70 degrees, not reducing traffic speed. It provides very high maneuverability when determinating and organizing points of stops, for landing and setting down persons and consignments, not having influence on the capacity ability of the main tube line. It also gives possibility to arrange more precisely the points of tube support in megalopolisis residential houses with a probability of up to 90% and in public buildings up to 100%, that is desirable for any category of persons and address deliveries of small-part consignments. It is even possible to lay the FlexiTaxi tube line between buildings standing at the distance of three meters from one to another.

The system of transportation is automated. A vehicle is ordered of single-, double-, three-, or of four-seats. The chairs inside have two degrees of freedom on axis, and it allows for passengers to have free dialogues (see drawing for illustrations of several component cross-sections).

The Second Attribute: city designing, relief of local area with accounting for seismicity

The tube system does not influence usual city structures contour lines, it is basic. Moreover, the height of tube emplacement allows passengers to survey the panorama of a city in any weather, and also to organize the largest in world running advertising system on external surfaces of the tube. Specialized damped crutch supports occupy very small area. Rope ties of the tube with top part of the damped crutch supports together with tube bottom metal frame constructions reinforced with plastic pipes on top of the tube frame provide significantly large free-of-crutch spans. It agrees with landscape and seismicity of the region. In cases of any resonance jumps or seismic displacements of ground, which could result in failures or breakages of some damped crutch supports, rope ties provide high warranty of reliability of the system, since the gross weight of the whole tube construction is rather small.

The optimization of the FlexiTaxi route is made by a gravitational method. The areas with increasing "gravity" mean places, in which increasing demands of vehicles are observed. The interlaying of a route is carried out on the vector of decreasing demands. As a result, the topological curve of a route in plane reminds a double closed spiral. It provides the existence of cyclicity for both vehicle movement and air flows inside the tube.

With such a method of tube layout, the speed of address delivery of the passengers and consignments is several times more, than in cases of using direct motorroads, subways and helicopters.

In the case of emergency, which forces an immediate evacuation of the passengers from the transport system, emergency windows are set and also a system of fixing passengers with net of strope suspensions is disposed outside the tube.

In the case of fire inside the tube, water and other put out substances are given between two plastic walls in fire-place. Such a method permits to exclude presence of the external firemen.

The level of water inside the tube is adjusted by natural drains.

The Third Attribute: propulsion peculiarities, delivery speed, stop mechanism

In the project there are two kinds of propulsion in the double route tube. The first kind: the transit is carried out by pneumatic directed pumping with the pressure of two atmospheres in the inner tube. The outer concentric tube is used for heating and cooling the traffic system, and also for locking on the vehicle station stops (see drawings of single-line and multi-level stations). This locking is used to provide for passengers to load and to set down. The second kind: the transit is carried out by electromagnetic propulsion and braking. In the first case, it is provided an average speed of 50 mph with a great maneuverability at turns, in the second case the speed is up to 120 mph with small maneuverability at turns. The maximum interval between the vehicles is from 10 to 15 seconds, which is absolutely acceptable for the safe control of the system.

The Fourth Attribute: the weight of the transit system, and its cost

Not taking into account damped crutch supports together with rope ties, the gross weight of the 50 meter system span is only six tons, of those are frame metal (90%), cables (1%), rivets (0.3%), plastic (2.7%), and also rubber band (1%) for using as layering material between the metal frame and plastic tubes. These materials are absolutely accessible. The estimate costs would be various for various coutries. But it is seemed to be not more, than the costs of traditional traffic systems, including project cost, trace layout cost, mounting cost, advertisements, etc.

Contact information: Professor Aslan Zakuraev or Victor Zholudev, Ph. D. , Nalchik, North Caucasus, Russia


Last modified: November 03, 1999