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TicPrio
— Traffic Signal Priority for Public Transport
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The
TicPrio-system provides buses, trams, and emergency vehicles priority
over other traffic at signalized intersections.
There are a large number of detector-loops in urban environments
for monitoring traffic at signalized junctions. In addition to performing
the classical detector function towards the Traffic Controller,
the TicPrio system also provides two-ways communication over detector
loops. Since the location of each loop is known, the position of
the vehicle can readily be determined.
The communication infrastructure is given through the loops. |
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| System
Components: |
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Detector loops in the ground, each connected to its own stationary
DETIC-unit for vehicle detection and inductive communication. Existing
loops can be used with preserved detector function. This means,
the DETIC will detect all kind of vehicles providing the classical
loop detector function in addition to its communication capability.
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Vehicle
mounted TIC-1R transmitter/receiver connected to an inductive antenna
for communication with the detector loops. |
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Push-button Panel connected to the TIC-1R for programming the route-number
and for manual selection of priority direction. |
TicPrio
stand-alone applications:
A fundamental requirement for stand-alone system is that the
priority direction corresponding to the bus route-number is
stored in the memory of the system’s roadside (DETIC)
unit. As the bus arrives on the entry-loop, this sends, to the
in-vehicle TIC-1R unit, the loop-ID including the information
that the loop is an entry-loop. The TIC-1R returns the route-number
to the roadside unit, which then finds the corresponding priority
direction and generates a priority request pulse for the Traffic
Controller. There is an output assigned for each priority direction
on the DETIC roadside unit.
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| Data
exchange between in-vehicle and roadside equipment. |
| The
bus driver can see the selected priority direction on a display
panel. The manual option, incorporated to allow route diversions
and detours, allows the driver to select the desired direction using
a push-button before the vehicle reaches the entry-loop. The system
ignores the automatic priority selection if a manual direction is
selected. Priority is terminated when the bus sends an exit-pulse
upon leaving the exit-loop at the junction. |
Integrating TicPrio with Intelligent Transport Systems:
If the bus or tram is fitted with a Vehicle Computer, this can
be connected to the TIC-1R through a serial channel. The stationary
system is the same as in TicPrio stand-alone systems. That means,
each loop is connected to its own DETIC-board. On approaching
an entry-loop, as identified by the DETIC roadside detector,
the vehicle computer selects the appropriate priority direction
and sends this via the TicPrio in-vehicle equipment through
the loop to the roadside DETIC-unit. The DETIC then generates
priority request pulse to the Traffic Controller. Again, the
loops provide the communication infrastructure, making additional
(e.g. radio or infra-red) links unnecessary.
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Overlapping
Systems:
In urban areas it’s likely that the buses/trams serving
the main routes might be equipped with Vehicle Computers, using
for example GPS for position updates to provide stop-info, arrival
announcements, etc. The PT-vehicles serving the minor city routes
or regional ones usually lack this equipment. Signal priority
at all junctions for all PT-vehicles might still be desirable.
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| Integrated
and stand-alone TicPriosystems can be operated in parallel to
solve this problem. Thus, the hardware is the same and the difference
between the stand-alone (route 173 in our example) and the integrated
(route 7) system is in the way of storing and transmitting the
priority directions corresponding to the route-number of the vehicle
and to the ID of the loop it encounters. |
Swarco
Technology ApS, Klokkestøbervej 21, 5230 Odense M, Denmark
Phone: +45 63 152 200, Fax: +45 63 152 219
e-mail: office@swtech.dk
Copyright © 2006 Swarco Technology ApS |
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TicPrio
(250KB) |
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Benefits
for Public Transport: |
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Gain in commercial speed;
Priority contributes to the reduction of
PT-vehicle journey times producing
greater transport capacity |
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Service regularity;
alignment with nominal timetables. |
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Reduction of pollution.
• A more rational use of energy.
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Example
of stand-alone application: |
| TicPrio
stand-alone applications are in operation in smaller cities. The
system does not need to keep track of buses’ position and
can operate without being connected to an automatic vehicle location
system. |
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| A
typical example of a stand-alone implementation is in the city of
Borås, Sweden. Its public transport fleet consists of 80 buses
with an established detector system based on 60 loops. |
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Example
of an integrated application: |
| TicPrio
can be integrated in real-time passenger information systems. The
in-vehicle Tic-equipment is connected to the vehicle computer through
a serial channel, allowing downloading of priority directions from
an AVL-system. |
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| An
example of an integrated TicPrio system is the implementation in
Gothenburg with its 200+ trams serving 13 lines and 350 buses plying
about 50 fixed routes. |
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Benefits
of using loops to provide Signal Priority: |
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Existing loops can be used with preserved detector function. |
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No communication costs. |
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No matter how many vehicles and loops in the system, communication
capacity is unlimited.
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Once
the vehicle is over a loop, communication is always guaranteed. |
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Negligible
comm. delays (from vehicle to Traffic Controller < 50 ms.). |
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Exact
vehicle positioning. |
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