Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02655457 2014-06-26
MID-BLOCK TRAFFIC DETECTION AND SIGNAL CONTROL
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of US provisional application
Serial Number 61/045,470 filed April 16, 2008 entitled "Mid-block Traffic
Detection and Signal Controller."
FIELD
[0002] The present invention relates generally to traffic detection and
signal control. More particularly, the present invention relates to mid-block
detection of commercial vehicles and signal control for regulation of traffic.
BACKGROUND
[0003] Transportation is one of the leading drivers of the world economy.
In particular, road freight transportation plays a major role in movement of
processed and unprocessed goods. Moreover, the use of heavy vehicles capable
of handling increased loads provides improved economic benefits. Movement of
commercial vehicles within urban areas is a very significant aspect in the
overall
freight path. Consequently, commercial vehicles are a substantial contributor
to
traffic congestion, road safety, increased wear and tear; and lead to negative
environmental impacts in urban areas.
[0004] Conventional traffic management systems in urban areas are
predominantly planned and designed for the effective control of passenger
vehicles. Heavy commercial vehicles (HCVs), are generally much larger in size,
and have different operating capabilities than passenger vehicles. For
example,
HCVs typically have greater stopping distances, longer acceleration times and
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larger turning radius. Traffic signal systems and controls in urban areas do
not
generally account for these differences and inherently lead to negative
impacts
on other road users.
SUMMARY OF DISCLOSED EMBODIMENTS
[0005] In a first aspect, a method is provided for mid-block detection of
vehicles comprising detecting a vehicle in a traffic lane; determining at
least one
pre-determined parameter of the vehicle; evaluating a traffic condition based
on
the at least one predetermined parameter; and controlling a traffic signal in
response to the evaluation of the traffic condition.
[0006] In one feature of this method, the at least one pre-determined
parameter is one of the following, namely, vehicle speed, vehicle length,
vehicle
weights; vehicle axle spacings; vehicle number of axles; and time and date of
detection of a vehicle.
[0007] In another feature of this method a pre-determined traffic signal
is
controlled in response to a plurality of detected vehicle parameters.
[0008] Generally, a method and a system are provided for mid-block traffic
detection and traffic signal control that is suited to monitoring heavy
commercial
vehicles, such as trucks. The method comprises detecting a vehicle and
determining at least one predetermined parameter of the vehicle. A traffic
condition is evaluated based on the at least one pre-determined parameter. In
response to the evaluation of the traffic condition, a traffic signal is
controlled.
[0009] In further aspect, a system is provided for mid-block detection of
vehicles comprising a sensor for detecting a vehicle in a traffic lane; a
processor
for determining at least one pre-determined parameter of the vehicle and for
evaluating a traffic condition based on the at least one pre-determined
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parameter, the processor controlling a traffic signal in response to the
evaluation
of the traffic condition.
[0010] In one feature of this system the at least one pre-determined
parameter is one of the following: vehicle speed; vehicle length; vehicle axle
weights; vehicle axle spacings; vehicle number of axles; and time and date of
detection of a vehicle.
[0011] In an aspect, the system for mid-block detection of vehicles
comprises a sensor for detecting a vehicle and a processor for determining at
least one pre-determined parameter of the vehicle. The processor evaluates a
traffic condition based on the at least one pre-determined parameter and
controls
a traffic signal in response to the evaluation of the traffic condition.
[0012] Other aspects and features of the present invention will become
apparent to those ordinarily skilled in the art upon review of the following
description of specific embodiments of the invention in conjunction with the
accompanying figures.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Embodiments of the present invention will now be described, by
way of example only, with reference to the attached Figures, wherein:
[0014] Fig. 1 s a flow diagram illustrating a method for controlling
traffic in
accordance with an embodiment;
[0015] Fig. 2 is a flow diagram illustrating an example of the method for
traffic control in accordance with the embodiment of Fig. 1;
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[0016] Fig. 3A is a flow diagram illustrating another example of the
method
for traffic control in accordance with the embodiment of Fig. 1;
[0017] Fig. 3B is a flow diagram illustrating yet another example of the
method for traffic control in accordance with the embodiment of Fig. 1;
[0018] Fig. 4 is a system for mid-block detection and traffic control in
accordance with an embodiment;
[0019] Fig. 5 is an illustration of various sensors for in-road detection
used
in an embodiment;
[0020] Fig. 6 is an illustration of non-intrusive detection devices used
in an
embodiment;
[0021] Figs. 7A-C are illustrations of on-board identification devices
used in
an embodiment;
[0022] Fig. 8A is a system for mid-block detection and traffic control in
accordance with an embodiment; and
[0023] Fig. 8B is a system for mid-block detection and traffic control in
accordance with an embodiment.
DETAILED DESCRIPTION
[0024] As discussed earlier, conventional traffic management systems in
urban areas are predominantly planned and designed for the effective control
of
passenger vehicles. (PCVs), having different operating capabilities than
passenger vehicles, are not efficiently monitored and controlled by
conventional
systems. The conventional traffic signal systems and controls in urban areas
do
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not generally account for the differences in operating capabilities of PCV's
resulting in hazardous conditions.
[0025] Accordingly, embodiments described herein provide a method and
system for mid-block detection of heavy commercial vehicles and signal control
for regulation of traffic.
[0026] As used herein, a Aheavy commercial vehicle@ refers to cargo
trucks, semitrucks, B-Doubles, Road-Trains, and other large sized trucks
collectively known as multi-combination vehicles (MCV).
[0027] The pre-determined parameters can include, among others, vehicle
speed. vehicle length, axle spacing, number of axles, weather conditions, road
or
intersection characteristics, and time and date of vehicle detection etc. The
pre-
determined parameters are recorded and an evaluation of the traffic condition
is
performed. In response, to the evaluation of the traffic condition or upon
determination of behavior triggering conditions being satisfied, one or more
traffic
signals are controlled.
[0028] Furthermore, in case of an error in the detection of the vehicle,
an
error detection log can be created for performance evaluation and maintenance
purposes.
[0029] In an exemplary embodiment, as shown in Fig. 1, the system
observes unsafe or sub-optimal traffic situations, and responds to them by
appropriately controlling the traffic signal. The exemplary system is designed
to
detect trucks and operating characteristics of trucks prior to entry or
approach to
a traffic intersection, such as at mid-block. Conventional systems do not
discern
trucks from the other vehicles in the traffic stream. Since the operating
characteristics of trucks differ greatly from automobile traffic, the
detection can
then be used as part of a larger logic process to modify the signal timing and
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phases to both enhance the movement of truck traffic, and prevent dangerous
situations that trucks may be exposed to as a result of the traffic signals
not
accommodating the unique nature of the truck traffic.
[0030] The exemplary embodiment is discussed in further detail in the
following exemplary scenarios.
Example 1
[0031] An HCV is behind a long trail of cars waiting for a traffic signal
to
turn green. The signal changes to green, but the slope of the road and the
heavy
load prevent the HCV from accelerating quickly enough to reach the
intersection
before the traffic signal changes to red again. In an embodiment of the
system,
this situation is recognized by analyzing the characteristics of traffic
approaching
the traffic signal and detecting the presence of the RCV. Based on the
evaluation
of the traffic condition, the length of the green signal is extended to give
the HCV
enough time to traverse the traffic signal, thereby clearing the intersection
and
preventing a dangerous stopping situation for the truck. Fig. 2 is a flow
diagram
illustrating this scenario.
Example 2
[0032] A heavily loaded truck travelling at some speed approaches a red
traffic signal. Due to its heavy load and configuration, the truck may be
incapable
of executing a safe stop at the red light. An embodiment of the system
recognizes the presence of the truck and observes its mass, velocity, and its
type. Based on this information, the system calculates whether the truck is
able
to stop, and if it cannot, the system changes the traffic signal to green
phase to
allow the safe passage of the traffic and thereby again reducing conflicts.
This
exemplary scenario is illustrated in Fig. 3B
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Example 3
[0033] A semi-truck traveling at a high speed approaches a green
traffic
signal. Due to its heavy load and configuration, the semi-truck may be
incapable
of executing a safe stop if the light were to turn red. An embodiment of the
system detects the presence of the truck and determines its mass, velocity,
and
its type. Based on this information, the system evaluates whether the truck is
able to stop. In the event the system determines that the semi-truck cannot
stop,
the system calculates the amount of time required for the safe passage of the
semi-truck. The system then extends the green and/or amber phase to allow the
safe passage of the traffic and thereby again reducing conflicts. Fig. 3B is a
flow
diagram illustrating this scenario.
[0034] Figure 4 is an exemplary embodiment of the system for mid-
block
detection and traffic control. As shown in Fig. 4, one or more sensors are
disposed in a traffic lane, or a plurality of traffic lanes, approaching a
traffic
signal. The sensors provide signals to the processor dependant on one or more
parameters of traffic traversing the sensors. The sensors are capable of
providing signals for distinguishing between general traffic (for example,
passenger vehicles) and HCV5 (for example, large trucks).
[0635] In addition, data storage having site-specific data, weather
data,
and other data logs stored therein can communicate with the processor. The
data
storage can be updated by the processor and/or other suitable external data
feeds, as shown in Fig. 4.
[0036] Various sensors can be used in conjunction with the
embodiments
of the system as shown in Fig. 5. For example, in-road sensors with
capabilities
of determining vehicle length can be used. Additionally, the sensors may be
capable of determining one or more of: the number of axles, spacing between
axles, weight of the axles, speed of the vehicle, and potentially the external
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dimensions of the vehicle. In-road sensors could use one or more existing or
still
to be developed technologies including inductive loops, magnetic detection
sensors, piezoelectric axle sensors, quartz axle sensors, bending plate
scales, or
load cell scales. The sensors may also be capable of measuring the vehicle
acceleration or deceleration.
[0037] In other embodiments, non-intrusive sensors mounted adjacent to
the road using radar, acoustic, laser, video or other means to characterize
vehicle types as shown in Fig. 6. The non-intrusive sensors can communicate
with the processors through various wired and wireless communication systems.
[0038] Further embodiments of the system can include communication
with a device located on the vehicle to transmit vehicle specific information,
such
as vehicle identification, vehicle type, or other specific vehicle
characteristics
such as weight. Vehicle specific information may be obtained directly from the
vehicle on-board computer (for example, GANBUS J1939) as shown in Fig. 7A,
from the vehicle on-board computer via an external communication/processing
device as shown in Fig. 7B, or an identification device added to the vehicle,
such
as a transponder as shown in Fig. 7G.
[0039] The processor uses data from the data storage and signals from
the sensors means to compute a traffic control signal that controls the
traffic
signal device. The processor determines various characteristics of vehicle
such
as speed and acceleration / deceleration, and the appropriate action of the
traffic
signal device.
[0040] The processor may be a separate processing unit that processes
and communicates with the traffic signal controller via RS232, Ethernet,
wireless
RF, contact closure or other appropriate communication method as shown in Fig.
8A. Alternately, processing
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= =
means may be contained as part of or added to traffic signal controller as
shown
in Fig. 5.
[0041] Embodiments of the system are connected to a traffic signal
device
associated with the traffic lane, or plurality of traffic lanes, and disposed
downstream from the sensors.
[0042] Generally, the system controls the traffic signal device(s)
downstream to facilitate management of HCV traffic. As noted above, the system
can adjust the traffic signals to accommodate heavy trucks in the traffic
pattern
that cannot easily accelerate along with the automobile traffic, or stop as
efficiently as the automobiles. For example, the system can extend the
duration
of green phases for stopped trucks that are fully loaded; lengthen the yellow
phases, or increase the all-red, or non-dilemma red phases.
[0043] An exemplary situation that will trigger the system to
manage the
traffic control in accordance with an embodiment is described below. As
described with respect to Fig. 2, a fully loaded truck is at rest at a
distance X
meters from a traffic signal. Under routine duration of a green phase of the
traffic
signal, the truck may not be able to safely traverse the traffic signal due to
the
truck's load and operating parameters. This situation can pose a potential
traffic
congestion problem or even a traffic hazard. The system can detect this
situation
and according adjust the duration of the green phase in order to accommodate
the truck by detecting the presence of the truck in the traffic approaching
the
intersection controlled by the traffic signal. The sensors detect the presence
of
the truck and communicate a number of pre-determined characteristics of the
truck to the processor. The processor analyses this information and outputs
control signals to the traffic controller to extend the duration of the green
phase in
real-time thereby providing a safe passage for the truck.
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[0044] Typically, a number of pre-determined parameters comprise are
collected by the sensors and communicated to the detector for the evaluation
of
circumstances that require the intervention of the system in order to manage
the
traffic controller. The information evaluated by the processor from the
parameter
data supplied by the sensors can include, for example, current status of
traffic
signal; weight of a vehicle; axle length of the vehicle; and velocity of the
vehicle
etc. The system can also detect the number of vehicles; weight of the
vehicles;
velocity of vehicles; and length .¨f vehicles etc.
[0045] The parameters that are sensed and monitored can be adjusted
based on the requirements of a particular traffic pattern, site-specific
information
etc. In most circumstances, a configuration of the vehicle (number and inter-
relationships of the axles), weight of the vehicle, and speed will enable the
system to compute safe stopping distances based on the site geometry. Using
this data, a database table of results can be established, giving the course
of
action for several different scenarios. For example, based on the type of the
HCV
and the speed computed, a Acannot stop@, may be able to stop@, and Ano
problem@ set of scenarios can be established. A course of action dependent
upon each of these scenarios can then be set in motion by the processor
through
the traffic controller, The course of action can be, for example, extending
the
green and yellow in a Acannot stop" scenario, while no action needs to be
taken
in a Ano problem@ scenario.
[0046] Under most traffic conditions, a traffic signal communicates a
current state to the processor and the in-road or non-intrusive sensors, such
as
weight sensors, axle length sensors, velocity sensors and means of sensing
number of vehicles, can provide information to the processor in real time. As
noted above, based on this information the processor can evaluate the
characteristics of an HCV present in the traffic. Furthermore, the processor
can
receive additional information on the traffic flow at any given time along
with
other relevant information such as weather dat? from a suitable database. The
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=
system evaluates different traffic scenarios and accordingly controls the
traffic
controller. For example, if there is very low traffic, then the system would
respond
differently than if there was a much higher level of traffic. The system
therefore
has not only the speed/configuration scenarios as indicated above, but
different
tables of results (or courses of action) depending on traffic conditions.
Thus, the
system can adaptively to control traffic under various traffic conditions.
[0047] In summary, embodiments of the system described herein are
capable of observing unsafe or sub-optimal traffic situations, and respond to
them by appropriately controlling the traffic signal thereby preventing
hazardous
conditions and reducing the negative impact of HCVs on other road users.
[0048] In the preceding description, for purposes of explanation,
numerous
details are set forth in order to provide a thorough understanding of the
embodiments of the invention. However, it will be apparent to one skilled in
the
art that these specific details are not required in order to practice the
invention. In
other instances, well-known electrical structures and circuits are shown in
block
diagram form in order not to obscure the invention. For example, specific
details
are not provided as to whether the embodiments of the invention described
herein are implemented as a software routine, hardware circuit, firmware, or a
combination thereof.
[0049] Embodiments of the invention can be represented as a software
product stored in a machine-readable medium (also referred to as a computer-
readable medium, a processor-readable medium, or a computer usable medium
having a computer-readable program code embodied therein). The machine-
readable medium can be any suitable tangible medium, including magnetic,
optical, or electrical storage medium including a diskette, compact disk read
only
memory (CD-ROM), memory device (volatile or nonvolatile), or similar storage
mechanism. The machine-readable medium can contain various ets of
instructions, code sequences, configuration information, or other data, which,
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when executed, cause a processor to perform steps in a method according to an
embodiment of the invention. Those of ordinary skill in the art will
appreciate that
other instructions and operations necessary to implement the described
invention
can also be stored on the machine-readable medium. Software running from the
machine-readable medium can interface with circuitry to perform the described
tasks.
[0050] The above-described embodiments of the invention are intended to
be examples only. Alterations, modifications and variations can be effected to
the
particular embodiments by those of skill in the art without departing from the
scope of the invention, which is defined solely by the claims appended hereto.
õ .
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