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
The Second Attribute: city designing, relief of local area with accounting for
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
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
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
Last modified: November 03, 1999