U.S. patent application number 10/829800 was filed with the patent office on 2005-10-27 for pavement marker and system for freeway advance accident merge signal.
Invention is credited to Safar, Samir H..
Application Number | 20050238425 10/829800 |
Document ID | / |
Family ID | 35136576 |
Filed Date | 2005-10-27 |
United States Patent
Application |
20050238425 |
Kind Code |
A1 |
Safar, Samir H. |
October 27, 2005 |
Pavement marker and system for freeway advance accident merge
signal
Abstract
A pavement marker includes a support structure adapted to be
mounted on a highway pavement intermediate first and second highway
lanes in a position visible to oncoming traffic. One or more red
and yellow lights are directed toward the oncoming traffic. A
sensor on it senses nearby traffic. A receiver on it receives an
incoming signal from a first companion pavement marker that is
mounted on the highway pavement more distant from the oncoming
traffic. A transmitter on it transmits an outgoing signal to a
second companion pavement marker that is mounted on the highway
pavement less distant from the oncoming traffic. A solar-charged,
battery-powered circuit controls operation according to information
from the sensor and the receiver in order to relay advance warning
of slowed, stopped, and all-clear traffic conditions to the
oncoming traffic via multiple spaced-apart pavement markers.
Inventors: |
Safar, Samir H.; (San Diego,
CA) |
Correspondence
Address: |
Loyal M. Hanson
Hanson Law Corporation
P.O. Box 430
Fallbrook
CA
92088-0430
US
|
Family ID: |
35136576 |
Appl. No.: |
10/829800 |
Filed: |
April 22, 2004 |
Current U.S.
Class: |
404/16 |
Current CPC
Class: |
E01F 9/559 20160201 |
Class at
Publication: |
404/016 |
International
Class: |
E01F 009/00 |
Claims
What is claimed is:
1. A pavement marker, comprising: a support structure adapted to be
mounted on a highway pavement intermediate first and second highway
lanes in a position visible to oncoming traffic; means on the
support structure for producing a light directed toward the
oncoming traffic, including at least one light-emitting circuit;
means on the support structure for sensing nearby traffic in order
to provide information related to nearby vehicle speed, including a
sensor; means on the support structure for receiving an incoming
signal from a first companion pavement marker that is mounted on
the highway pavement more distant from the oncoming traffic,
including a receiver; means on the support structure for
transmitting an outgoing signal to a second companion pavement
marker that is mounted on the highway pavement less distant from
the oncoming traffic, including a transmitter; and means on the
support structure for controlling operation of the light-emitting
circuit and the transmitter according to information obtained from
the sensor and the receiver in order to provide advance warning of
traffic conditions to the oncoming traffic, including an electronic
circuit with a circuit-powering battery and a battery-charging
solar cell assembly; wherein the electronic circuit is adapted to
control operation under program control in order to relay the
information related to nearby vehicle speed from the first
companion marker to the second companion marker and thereby relay
the information toward oncoming traffic as an advance warning of
traffic conditions ahead of the oncoming traffic.
2. (canceled)
3. A pavement marker as recited in claim 1, wherein the
light-emitting circuit includes at least one red light-emitting
component and at least one yellow light-emitting component.
4. A pavement marker as recited in claim 1, wherein the electronic
circuit is adapted to respond to the sensor detecting an occurrence
of the presence of a nearby vehicle for more than a first
predetermined period of time by activating the light-emitting
circuit and transmitting an INITIAL OUTGOING SLOWED-VEHICLE signal
to the second companion pavement marker.
5. A pavement marker as recited in claim 4, wherein the electronic
circuit is adapted to respond to the receiver receiving an INCOMING
SLOWED-VEHICLE signal from the first companion pavement marker by
activating the light-emitting circuit, disregarding the sensor,
incrementing a counter valve to produce a new counter valve, and
transmitting a RELAYED OUTGOING SLOWED-VEHICLE signal indicative of
the new counter valve to the second companion pavement marker.
6. A pavement marker as recited in claim 5, wherein the electronic
circuit is adapted to not transmit the RELAYED OUTGOING
SLOWED-VEHICLE signal if the counter valve reaches a predetermined
maximum valve.
7. A pavement marker as recited in claim 5, wherein the electronic
circuit is adapted to respond to the sensor detecting an occurrence
of the presence of a nearby vehicle for less than the first
predetermined period of time after transmitting the INITIAL
OUTGOING SLOWED-VEHICLE signal by deactivating the light-emitting
circuit and transmitting an ALL-CLEAR signal to the second
companion pavement marker.
8. A pavement marker as recited in claim 1, wherein the electronic
circuit is adapted to respond to the sensor detecting an occurrence
of the presence of a nearby vehicle for more than a second
predetermined period of time by activating the light-emitting
circuit and transmitting an INITIAL OUTGOING STOPPED-VEHICLE signal
to the second companion pavement marker.
9. A pavement marker as recited in claim 8, wherein the electronic
circuit is adapted to respond to the receiver receiving an INCOMING
STOPPED-VEHICLE signal from the first companion pavement marker by
activating the light-emitting circuit, disregarding the sensor,
incrementing a counter valve to produce a new counter valve, and
transmitting a RELAYED OUTGOING STOPPED-VEHICLE signal indicative
of the new counter valve to the second companion pavement
marker.
10. A pavement marker as recited in claim 9, wherein the electronic
circuit is adapted to not transmit the RELAYED OUTGOING
STOPPED-VEHICLE signal if the counter valve reaches a predetermined
maximum valve.
11. A pavement marker as recited in claim 9, wherein the electronic
circuit is adapted to respond to the sensor detecting an occurrence
of the presence of a nearby vehicle for less than the first
predetermined period after transmitting the INITIAL OUTGOING
STOPPED-VEHICLE signal by deactivating the light-emitting circuit
and transmitting an ALL-CLEAR signal to the second companion
pavement marker.
12. A method for providing an advance warning of traffic conditions
to oncoming traffic, comprising: providing a plurality of
battery-powered, solar-charged pavement markers that are adapted to
be mounted on a highway pavement, such that each pavement marker is
adapted to sense nearby traffic and emit light as a warning of
traffic conditions and such that each of the pavement markers
includes an electronic circuit that is adapted to operate under
program control as means for receiving and responding to a signal
from a first companion pavement marker that is more distant from
the oncoming traffic, and transmitting a signal to a second
companion pavement marker that is less distant from the oncoming
traffic, in order to thereby relay a SLOWED-TRAFFIC warning and a
STOPPED-TRAFFIC warning of traffic conditions via the pavement
markers toward the oncoming traffic; mounting the plurality of
pavement markers on the highway pavement in spaced-apart locations
along the highway intermediate first and second highway lanes so
that the light emitted is visible to oncoming traffic; and relaying
information related to nearby traffic from the first companion
marker to the second companion pavement marker as an advance
warning to the oncoming traffic of traffic conditions.
13. A traffic warning system, comprising: a plurality of similar
pavement markers mounted at spaced apart positions on a highway
pavement, including at least a first pavement marker, a second
pavement marker, and a third pavement marker; each of the first,
second, and third pavement markers including a respective one of
first, second, and third support structures such that the support
structures are adapted to be mounted on a highway pavement in
spaced apart positions visible to oncoming traffic; the second
pavement marker including means on the second support structure for
producing light directed toward the oncoming traffic, including at
least one light-emitting circuit; the second pavement marker
including means for sensing nearby traffic in order to provide
information related to nearby vehicle speed, including a sensor;
the second pavement marker including means for receiving an
incoming signal from the first pavement marker, including a
receiver; the second pavement markers including means for
transmitting an outgoing signal to the third pavement marker,
including a transmitter; and the second pavement marker including
an electronic circuit adapted to operates under program control as
means for controlling operation of the light-emitting circuit and
the transmitter according to information obtained from the sensor
and the receiver in order to activate the light-emitting circuit
and relay a warning of traffic conditions via the transmitter to
the third pavement marker and thereby toward the oncoming traffic;
wherein the electronic circuit is adapted to respond to the sensor
detecting an occurrence of the presence of a nearby vehicle for
more than a first predetermined period of time by activating the
light-emitting circuit and transmitting an INITIAL OUTGOING
SLOWED-VEHICLE signal to the third pavement marker; wherein the
electronic circuit is adapted to respond to the receiver receiving
an INCOMING SLOWED-VEHICLE signal from the first pavement marker by
activating the light-emitting circuit, disregarding the sensor,
incrementing a counter valve to produce a new counter valve, and
transmitting a RELAYED OUTGOING SLOWED-VEHICLE signal indicative of
the new counter valve to the third pavement marker; and wherein the
electronic circuit is adapted to not transmit the RELAYED OUTGOING
SLOWED-VEHICLE signal if the counter valve reaches a predetermined
maximum valve.
14. A pavement marker as recited in claim 13, wherein the
electronic circuit is adapted to respond to the sensor detecting an
occurrence of the presence of a nearby vehicle for less than the
first predetermined period of time after transmitting the INITIAL
OUTGOING SLOWED-VEHICLE signal by deactivating the light-emitting
circuit and transmitting an ALL-CLEAR signal to the third companion
pavement marker.
15. A pavement marker as recited in claim 13, wherein the
electronic circuit is adapted to respond to the sensor detecting an
occurrence of the presence of a nearby vehicle for more than a
second predetermined period of time by activating the
light-emitting circuit and transmitting an INITIAL OUTGOING
STOPPED-VEHICLE signal to the third pavement marker.
16. A pavement marker as recited in claim 13, wherein the
electronic circuit is adapted to respond to the receiver receiving
an INCOMING STOPPED-VEHICLE signal from the first pavement marker
by activating the light-emitting circuit, disregarding the sensor,
incrementing a counter valve to produce a new counter valve, and
transmitting a RELAYED OUTGOING STOPPED-VEHICLE signal indicative
of the new counter valve to the third pavement marker.
17. A pavement marker as recited in claim 16, wherein the
electronic circuit is adapted to not transmit the RELAYED OUTGOING
STOPPED-VEHICLE signal if the counter valve reaches a predetermined
maximum valve.
18. A pavement marker as recited in claim 13, wherein the
electronic circuit is adapted to respond to the sensor detecting an
occurrence of the presence of a nearby vehicle for less than the
first predetermined period after transmitting the INITIAL OUTGOING
STOPPED-VEHICLE signal by deactivating the light-emitting circuit
and transmitting an ALL-CLEAR signal to the third pavement marker.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Technical Field
[0002] This invention relates generally to highway design and
construction, and more particularly to a pavement marker and system
for automatically providing a multi-lane highway merge signal to
drivers.
[0003] 2. Description of Related Art
[0004] A driver on a multi-lane highway must often merge left or
right into an adjacent lane when approaching the scene of an
automobile accident, debris on the pavement, or other obstacle that
causes traffic to slow down. Doing so can be extremely dangerous,
especially during rush hour and at highway speeds. In order to
alleviate this concern, portable and fixed programmable signs are
sometimes used along the freeway to forewarn drivers of an obstacle
ahead.
[0005] However, the portable and fixed programmable sign approach
has certain drawbacks. Although, a portable sign can sometimes be
quickly dispatched to an accident scene, doing so nevertheless
takes a significant amount of time. Fixed signs, on the other hand,
are useable only in the location where they are erected. In
addition, both portable and fixed signs must be programmed at the
time needed with the message they are to display.
[0006] There are numerous existing methods and warning devices of
road hazard warning systems. For example, there are lighted test
signs that indicate the location of highway problems, merge signs
on stationary or moving vehicles, traffic stations on the radio,
and periodic traffic updates on various radio stations. But, there
is no instant warning system for the incoming driver as an accident
happens. Thus, a need exists for a better way to provide an advance
warning in the form of an automatic merge signal to freeway
drivers.
SUMMARY OF THE INVENTION
[0007] This invention addresses the concerns outlined above by
providing a pavement marker that combines with similar companion
pavement markers to provide the desired merge signal. The pavement
markers are disposed at space-apart locations along lane-dividing
lines on the highway. Each pavement marker is a solar-charged,
battery-powered device outfitted with a traffic sensor, red and
yellow lights, transmitter and receiver modules, and control
circuitry. Each pavement marker communicates with adjacent pavement
markers to relay a traffic warning about slowed or stopped vehicle,
illuminating the red and yellow lights appropriately to provide a
freeway advance accident merge signal (FAAMS) to drivers.
[0008] To paraphrase some of the more precise language appearing in
the claims and further introduce the nomenclature used, a pavement
marker constructed according to the invention includes a support
structure adapted to be mounted on a highway pavement intermediate
first and second highway lanes in a position visible to oncoming
traffic. A light-emitting circuit is provided on the support
structure for producing a light directed toward the oncoming
traffic, together with a sensor for sensing nearby traffic in order
to provide information related to nearby vehicle speed, a receiver
for receiving an incoming signal from a first companion pavement
marker that is mounted on the highway pavement more distant from
the oncoming traffic in order to receive information related to
traffic conditions more distant from the oncoming traffic than the
support structure. A transmitter is provided in addition for
transmitting an outgoing signal to a second companion pavement
marker that is mounted on the highway pavement less distant from
the oncoming traffic in order to transmit outgoing information
related to traffic conditions. A battery-powered, solar-charged
circuit on the support structure controls operation of the
light-emitting circuit and the transmitter according to information
obtained from the sensor and the receiver in order to provide
advance warning of traffic conditions to the oncoming traffic via
multiple pavement markers.
[0009] Preferably, the electronic circuit is adapted to control
operation under program control and the light-emitting circuit
includes at least one red light-emitting component and at least one
yellow light-emitting component. In one embodiment, the electronic
circuit is adapted to respond to the sensor detecting an occurrence
of the presence of a nearby vehicle for more than a first
predetermined period of time (e.g., 30 seconds) by activating the
light-emitting circuit and transmitting an INITIAL OUTGOING
SLOWED-VEHICLE signal to the second companion pavement marker.
[0010] In addition, the electronic circuit is preferably adapted to
respond to the receiver receiving an INCOMING SLOWED-VEHICLE signal
from the first companion pavement marker by activating the
light-emitting circuit, disregarding the sensor, incrementing a
counter valve to produce a new counter valve, and transmitting a
RELAYED OUTGOING SLOWED-VEHICLE signal indicative of the new
counter valve to the second companion pavement marker. The
electronic circuit is adapted to not transmit the RELAYED OUTGOING
SLOWED-VEHICLE signal if the counter valve reaches a predetermined
maximum valve (e.g., 200) so that the slowed traffic information is
only relayed toward the oncoming traffic by that number of pavement
markers.
[0011] Preferably, the electronic circuit is also adapted to
respond to the sensor detecting an occurrence of the presence of a
nearby vehicle for less than the first predetermined period of time
after transmitting the INITIAL OUTGOING SLOWED-VEHICLE signal by
deactivating the light-emitting circuit and transmitting an
ALL-CLEAR signal to the second companion pavement marker. Operation
is preferably similar in the case of a stopped vehicle. The
electronic circuit is adapted to respond to the sensor detecting an
occurrence of the presence of a nearby vehicle for more than a
second predetermined period of time (e.g., 90 seconds) by
activating the light-emitting circuit and transmitting an INITIAL
OUTGOING STOPPED-VEHICLE signal to the second companion pavement
marker.
[0012] Thus, the invention provides a pavement marker that combines
with similar companion pavement markers to provide the desired
merge signal. Each pavement marker communicates with adjacent
pavement markers to relay a traffic warning about slowed or stopped
vehicle, illuminating the red and yellow lights appropriately to
provide a freeway advance accident merge signal (FAAMS) to
drivers.
[0013] The invention provides immediate warning, miles ahead, to
incoming traffic that there is a hazard on the road or a blocked
lane ahead. It keeps the traffic flowing more smoothly by
indicating to the incoming traffic which lane is blocked due to a
stalled vehicle, accident, or other problem affecting the flow of
traffic in a particular lane. Incoming traffic is able to smoothly
and gradually merge toward the open lanes because the system of
this invention specifically indicates which lane is blocked so that
drivers will be able to avoid that lane. Motorists will be less
likely to miss the warning indicators because they are always in
front of them. For tunnels, curved roads, or unlit roads, the
system gives warning prior to entering the blind areas. The
following illustrative drawings and detailed description make the
foregoing and other objects, features, and advantages of the
invention more apparent.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 of the drawings is an isometric view of a pavement
marker constructed according to the invention;
[0015] FIG. 2 is a blown apart view of the pavement marker;
[0016] FIG. 3 is a block diagram of the pavement marker;
[0017] FIG. 4 is a circuit diagram that illustrates suitable
circuitry;
[0018] FIGS. 5a, 5b, 5c, and 5d combine at points labeled A, B, C,
and D to form a flow chart that is descriptive of software in the
program memory in the microcontroller portion of the control
circuitry;
[0019] FIG. 6 is a diagrammatic representation of a four-lane
highway having two left bound lanes and two right bound lanes
separated by lane dividers, with pavement markers disposed at
intervals along the lane dividers;
[0020] FIG. 7 is a diagrammatic representation similar to FIG. 6,
but with the traffic in the innermost left bound lane (i.e., the
first left bound lane) slowed; and
[0021] FIG. 8 is a diagrammatic representation similar to FIG. 6,
but with the traffic in the first left bound lane stopped.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0022] FIGS. 1-7 of the drawings show various aspects of a pavement
marker 10 constructed according to the invention.
[0023] Generally, the pavement marker 10 includes a support
structure in the form of a housing 11 (e.g., metal) and a circuit
module 12 on the housing 11 (FIGS. 1 and 2). Those components may
be similar in some general respects to existing pavement markers,
including the pavement marker described in U.S. Pat. No.
6,602,021.
[0024] The housing 11 is adapted to be mounted on a highway
pavement intermediate first and second highway lanes in a position
visible to oncoming traffic. It is so adapted in the sense that it
is sufficiently rigid, durable, and small to present a low profile
and withstand vehicles driving over it (inadvertently or when
changing lanes). It may be similar structurally to existing
pavement markers in that respect.
[0025] The circuit module 12 within the housing 11 includes a
battery-powered, solar-charged circuit that is described later on
with reference to FIGS. 3, 4, and 5a-5d. The circuit module 12 fits
into a main section 13 of the housing 11 with a solar panel 14
portion of the circuit (also described later on) facing upwardly. A
bottom cover 15 is mounted on the main section 13 of the housing 11
to retain the circuit module 12 in place.
[0026] A lens 16 is mounted on a first side 17 of the main section
13 over a first light-emitting circuit 18 (e.g., multiple red LEDs)
and a second light-emitting circuit 19 (e.g., multiple yellow LEDs)
on the circuit module 12 to face oncoming traffic. An
RF-transparent plate 20 is mounted on an opposite second side 21
where it admits an incoming RF signal to the circuit module 12 as
described later on. An opening 22 is provided in the main section
12 through which a sensor 23 on the circuit module 14 operates in
sensing the presence of nearby vehicles.
[0027] As an idea of size, the illustrated housing 11 measures
about five to six inches on each side and about one inch in height.
Of course, those dimensions may vary without departing from the
invention. Based upon the foregoing and subsequent descriptions,
one of ordinary skill in the art can readily implement the housing
aspects (i.e., the support structure aspects) of the invention.
[0028] Turning now to the block diagram in FIG. 3, it shows further
details of battery-powered, solar charged circuitry on the circuit
module 12. The solar panel 14 charges a battery 25 that powers a
control circuit 26. The control circuit 26 receives a sensor signal
from the sensor 23 and a receiver signal from a receiver 27 located
toward the RF transparent plate 20 shown in FIGS. 2 and 3. The
control circuit 26 responds to the sensor signal and the receiver
signal (received from a companion pavement marker located more
distant from oncoming traffic than the pavement marker 10) by
turning on and off the first or red light-emitting circuit 18 and
the second or yellow light-emitting circuit 19 according to traffic
conditions. It also causes a transmitter 28 (located toward the
lens 16) to transmit a related transmitter signal to a companion
pavement marker less distant from oncoming traffic.
[0029] FIG. 4 is a schematic circuit diagram of a breadboard model
30 of the control circuitry shown in FIG. 3 that illustrates a
suitable circuit arrangement. It uses known components and design
techniques to achieve the functions desired. A commercially
available programmable microcontroller 31 is used to simulate the
primary part of the control circuit 26. The microcontroller 31 is
powered by a 6-volt battery pack 32 (representing the battery 25 in
FIG. 3), and the battery pack 32 is, in turn, charged by a solar
panel 33 (e.g., 5 volts at 180 milliampere). An on/off switch 34 is
provided for convenience.
[0030] The microcontroller 31 controls (under program control) a
commercially available 12-bit encoder 35 and a commercially
available 12-bit decoder 36. The encoder 35 encodes information
that is coupled to a commercially available transmitter module 37
(e.g., a 300 MHz AM transmitter) for encoding on a transmitter
signal transmitted by the transmitter module 37. The decoder 36
decodes information encoded on a receiver signal that the decoder
36 receives from a commercially available receiver module 38 (e.g.,
a 300 MHz AM receiver).
[0031] A commercially available sensor 39 supplies a sensor signal
to the microcontroller 31 that is indicative of the speed of a
nearby vehicle. The microcontroller 31 uses information derived
from the sensor signal and the receiver signal to turn on and off a
first light-emitting circuit (e.g., a plurality of commercially
available ultra-bright red light-emitting LEDs 40) and a similar
second light-emitting circuit (e.g., a plurality of ultra-bright
yellow light-emitting LEDs 41), in addition to causing the
transmitter module 37 to transmitter a transmitter signal. Based
upon the foregoing and subsequent descriptions, one of ordinary
skill in the art can readily implement suitable circuitry for the
pavement marker 10.
[0032] The microcontroller 31 is programmed according to know
programming techniques to perform the functions desired. FIGS. 5a,
5b, 5c, and 5d combine at points labeled A, B, C, and D to form a
high level flow chart that is descriptive of software in the
program memory in the microcontroller 31. The program start (block
41 in FIG. 5a) is the section of the software in the program memory
that lists the specific microcontroller type that is used along
with the name of the INCLUDE file. One of ordinary skill in the art
will recognize that these configurations are necessary when the
software is transferred from a personal computer used for
programming purposes to the microcontroller 31. The program start
(block 41) also states the variable assignments. The variable
assignments give the variable letter designation of all the
variables used in the program along with their location in the
program memory.
[0033] The mainline program (block 42) starts the primary
subroutine of the program and denotes the beginning of that
particular section of the program. The setting initial values
(block 43) sets initial valves for each of the variables assigned
in block 41.
[0034] These variables and their initial values are used to perform
a variety of tasks throughout the execution of the program. The
port initialization (block 44) is performed for each port used by
the program on the microcontroller. Port initialization configures
the pins of the microcontroller 31 so that they are capable of
performing the particular tasks needed by the software in the
program memory of the microcontroller 31.
[0035] The main LOOP (block 45) is a subroutine that is part of the
mainline program in 42. The main LOOP repeats its execution until
an interrupt request is received by the microcontroller 31 via the
receiver module 38 from an up-line unit (i.e., a first companion
pavement marker that is more distant from oncoming traffic). Once
the interrupt is complete the program continues to execute the main
LOOP. The specific code that is executed as parts of the main LOOP
is explained for the read sensor (block 46 in FIG. 5a) and for the
blocks in FIGS. 5c and 5d. The proximity sensor value (the voltage
of the sensor signal from the sensor 39) is read by the
microcontroller 31 approximately three times per second (block 46).
The proximity sensor sends the sensor valve as an analog voltage
value to one of the pins of the microcontroller 31. The
microcontroller 31 reads that value and compares it to a fixed
value to determine if an object is within predetermined range
specifications.
[0036] The interrupt routine (block 47 in FIG. 5b) is the section
of the software in the program memory of the microcontroller 31
that handles communications sent from the up-line unit. The up-line
unit transmits the value of a traffic-delay-indicating variable D
to the pavement marker 10 which is down-line from it (i.e., closer
to oncoming traffic). The microcontroller 31 then interrupts its
execution of the main LOOP at block 45 to read the value of D into
the microcontroller. The interrupt routine only returns to the main
LOOP at block 45 when a zero value for variable D is read by the
unit that receives the interrupt request. A value of zero for
variable D then turns OFF the red or yellow LEDs. When an interrupt
request is received by the microcontroller 31 via the receiver
module 38 and the decoder 36, the value is read and transferred
into the register of variable D. The value of variable D is then
compared to fixed values pre-programmed into the software in the
program memory of the microcontroller 31.
[0037] The value of variable D received during the interrupt
request is compared. If the value of variable D is greater than 5,
then the Yellow LEDs are turned ON (block 49), and the value of
variable D greater than 5 is sent to the output pins of the
microcontroller 31. The encoder 35 that is connected to the output
pins of the microcontroller 31 sends the value of variable D to the
wireless transmitter module 37 for transmission to command the
down-line unit (the second companion pavement marker that is less
distant from oncoming traffic) to turn ON its yellow LEDs (block
49A). Following the transmission of the value of variable D to the
down-line unit, the software in the program memory of the
microcontroller 31 waits for another interrupt request from the
adjacent up line unit (block 50). The interrupt request received
from the up-line unit will either tell the unit to turn ON the red
LEDs or turn OFF the red or yellow LEDs and return to the main LOOP
subroutine.
[0038] If the value of variable D that is read during the interrupt
request is between 1 and 5, then the red LEDs are turned ON (block
51). The value of variable D between 1 and 5 is sent to the output
pins of the microcontroller 31 that is connected to the encoder 35.
The encoder 35 then sends the value of variable D to the wireless
transmitter module 37 for transmission to command the down-line
unit to turn ON the red LEDs (block 51A). Following the
transmission of the value of variable D to the adjacent down line
unit the software in the program memory of the microcontroller 31
waits for another interrupt request from the up-line unit (block
52). The interrupt request received from the up-line unit will
command the unit to turn OFF the red LEDs.
[0039] If the value of D that is read during the interrupt request
is is zero, then the red or yellow LEDs are turned OFF depending on
which one was turned ON prior to being turned OFF (block 52). The
value of variable D that is equal to zero is sent to the output
pins of the microcontroller 31 that are connected to the encoder
35. The encoder 35 then sends the value of variable D to the
wireless transmitter module 37 (block 53A) for transmission to the
down-line unit to command the down-line unit to turn OFF the red or
yellow LEDs, depending on which one is turned ON prior to being
turned OFF. The CALL command for the main LOOP (block 54) moves the
program counter to the beginning of the LOOP subroutine to repeat
the execution of the subroutine. The subroutine LOOP is repeated
continuously until an interrupt request is received from the
up-line unit via the receiver module 38 that commands the unit to
turn ON the red or yellow LEDs, or turn them OFF.
[0040] The analog voltage value read by the microcontroller 31 is
compared (block 55 in FIG. 5c) to fixed values pre-programmed into
the software in the program memory of the microcontroller 31. The
sensor voltage values compared are those less than 0.6 volts (a
predetermined minimum value) and greater than 2.5 volts (a
predetermined maximum value). Depending on the sensor's voltage
level read by the microcontroller 31, the red LEDs or yellow LEDs
are turned OFF (block 56). If the voltage level of the sensor is
read to be less than 0.6 volts or greater than 2.5 volts during a
sample taken three times per second, then the red or yellow LEDs
are turned OFF if they were already turned ON. When a change in the
state to turn OFF the red or yellow LEDs is detected, a value of
zero is transferred to the register of variable D. That value of
variable D is then transmitted (block 57) to command the down-line
unit to turn OFF the red or yellow LEDs. The value of variable D is
transmitted through the output pins of the microcontroller 31
connected to the encoder 35. The encoder 35 is connected to the
wireless transmitter module 37 that transmits the value of variable
D to the down-line unit. When a wireless transmission to the
down-line unit is complete, the program repeats the main LOOP
subroutine from the beginning (block 58). It goes to block 45 in
FIG. 5a and repeats the code execution.
[0041] At block 59 FIG. 5d, the sensor's analog voltage value read
by the microcontroller 31 and compared to the fixed values
pre-programmed in the software of the microcontroller 31. If the
voltage level of the sensor is between 0.6 volts and 2.5 volts,
then an object (e.g., a vehicle) is within a pre-specified range.
If the voltage read by the microcontroller 31 is between 0.6 volts
and 2.5 volts then the value of a timing variable X is incremented
by one.
[0042] At block 60, the value of variable X is compared to a
predetermined variable value of T representing a predetermined
minimum period of time (e.g., 30 seconds). If the value of variable
X is less than the value of variable T then a CALL command is
executed for the subroutine LOOP to repeat the LOOP subroutine
again to read another sample voltage level from the sensor. At
block 61, the value of variable X is compared to a predetermined
variable value Y representing a predetermined maximum period of
time (e.g., 90 seconds). If the value of variable X is greater than
the value of variable Y, then the red LEDs are turned ON. The value
of variable D is then set to two. The value placed in the register
of variable D is then transmitted to the down-line unit (block 62)
to command the units to turn ON their red LEDs. The value of D is
sent via the output pins of the microcontroller 31 connected to the
encoder 35. The encoder 35 is connected to the wireless transmitter
module 37 that transmits the value of variable D to the down-line
unit. The CALL command for the main LOOP (block 63) moves the
program counter to the beginning of the LOOP subroutine to repeat
the execution of the subroutine. The subroutine LOOP is repeated
continuously until an interrupt request is received from an
adjacent up line unit that commands the unit to turn ON the red or
yellow LEDs, or to turn them OFF.
[0043] At block 64, the value of variable X is compared to fixed
variable values T and Y. If the value of variable X is greater than
variable T and less than variable Y, the yellow LEDs are turned ON
and the value of variable D is set to 6. The value placed in the
register of variable D is then transmitted to the down-line unit
(block 65) to command the down-line unit to turn ON the yellow
LEDs. The value of variable D is sent through the pins of the
microcontroller 31 connected to the encoder 35. The encoder 35 is
connected to the wireless transmitter module 37 that transmits the
value of variable D to the down-line unit. The CALL command for the
main LOOP (block 66) moves the program counter to the beginning of
the LOOP subroutine to repeat the execution of the subroutine. The
subroutine LOOP is repeated continuously until an interrupt request
is received from an adjacent up-line unit that commands the unit to
turn ON the red or yellow LEDs, or to turn them OFF. Based upon the
foregoing, one of ordinary skill in the art can readily program the
microcontroller 31 to function as desired.
[0044] Operation is illustrated pictorially in FIGS. 6, 7, and 8
for traffic on a typical highway having two lanes in a first
direction (that is left bound from the viewpoint of a reader) and
two lanes in a second direction that is right bound from the
viewpoint of the reader. First consider FIG. 6. It shows the
highway having a central highway divider 70 (e.g., a median strip)
between left bound and right bound traffic. A first left bound lane
71 on a first side of the highway divider 70 is bounded on the left
side of traffic by a first left bound lane divider line 72. A
second left bound lane 73 is bounded on the left side of traffic by
a second left bound lane divider line 74 on the left side of
traffic in the second left bound lane 73. First and second right
bound lanes 75 and 76 on an opposite side of the highway divider 70
are arranged in a similar manner.
[0045] Pavement markers 73A through 73F are mounted on the highway
pavement at uniformly spaced-apart intervals on the first lane
divider line 72. Pavement markers 74A through 74F are mounted on
the highway pavement at uniformly spaced-apart intervals on the
second lane divider line 74. The resulting lines of spaced-apart
pavement markers continues in both directions with additional
pavement markers (not shown).
[0046] Vehicles 81 and 82 (and vehicles following after them) are
oncoming traffic relative to the pavement markers 73A, 73B, and
73C. Similarly, vehicles 83 and 84 (and vehicles following after
them) are oncoming traffic relative to pavement markers 74A, 74B,
and 74C. Focusing on the pavement marker 73C as representing the
pavement marker 10 described above, the pavement marker 73B
represents the first companion pavement marker mentioned previously
that is located more distant from the oncoming traffic. Similarly,
the pavement marker 73D represents the second companion pavement
marker mentioned previously that is located less distant from the
oncoming traffic.
[0047] In operation, the pavement marker 73C senses the presence of
a nearby vehicle 83 as that vehicle passes by the pavement marker
73B. If the vehicle 83 is sensed for less than 30 seconds, red and
yellow lights remain off. If the vehicle 83 is sensed between 30
seconds and 90 seconds, however, the yellow light is turned on and
an INITIAL OUTGOING SLOWED-VEHICLE signal is transmitted to the
second companion pavement marker 73D for relay to pavement markers
73E and 73F, and onward down-line toward oncoming traffic between a
predetermined number (e.g., 200) of companion pavement markers. The
pavement marker 73D receives that signal as an INCOMING
SLOWED-VEHICLE signal and it responds by disregarding the sensor
signal from its own sensor, activating its yellow light,
incrementing a counter valve to produce a new counter valve, and
transmitting a RELAYED OUTGOING SLOWED-VEHICLE signal indicative of
the new counter valve to the next down-line companion pavement
marker 73E. The pavement marker 73F receives the RELAYED OUTGOING
SLOWED-VEHICLE signal as an INCOMING SLOWED-VEHICLE signal and
responds in much the same way. The yellow-light-on state is
depicted in FIG. 7 by cross hatching on the pavement markers 73C,
73D, 73E, and 73F.
[0048] If the vehicle 83 is sensed for more than 90 seconds, the
yellow light is turned off, the red light is turned on and an
INITIAL OUTGOING STOPPED-VEHICLE signal is transmitted to the
second companion pavement marker 73D for relay to pavement markers
73E and 73F, and onward down-line toward oncoming traffic between
the predetermined number of companion pavement markers in a manner
similar to that described above for slowed traffic. The pavement
marker 73D receives that signal as an INCOMING STOPPED-VEHICLE
signal and it responds by disregarding the sensor signal from its
own sensor, activating its red light, incrementing a counter valve
to produce a new counter valve, and transmitting a RELAYED OUTGOING
STOPPED-VEHICLE signal indicative of the new counter valve to the
next down-line companion pavement marker 73E. The pavement marker
73F receives the RELAYED OUTGOING STOPPED-VEHICLE signal as an
INCOMING STOPPED-VEHICLE signal and responds in much the same way.
The red-light-on state is depicted in FIG. 8 by a black fill for
the pavement markers 73C, 73D, 73E, and 73F.
[0049] Eventually, traffic begins to move again after a slowed or
stopped state. When that happens, the pavement marker 73C responds
to its sensor detecting an occurrence of the presence of a nearby
vehicle for less than the 30 seconds by deactivating its
light-emitting circuit (i.e., its red or yellow light) and
transmitting an ALL-CLEAR signal to the second companion pavement
marker for relay toward the oncoming traffic so that the other
pavement markers also deactivate their light-emitting circuits.
[0050] Thus, the invention provides a pavement marker that combines
with similar companion pavement markers to provide the desired
merge signal. Each pavement marker communicates with adjacent
pavement markers to relay a traffic warning about slowed or stopped
vehicle, illuminating red and yellow lights appropriately to
provide a freeway advance accident merge signal (FAAMS) to
drivers.
[0051] Although an exemplary embodiment has been shown and
described, one of ordinary skill in the art may make many changes,
modifications, and substitutions without necessarily departing from
the spirit and scope of the invention. Communication between
modules using infrared signals may be use instead of RF signals,
for example, thereby eliminating the use of address settings for
each unit. In addition, various sophisticated refinements in
program logic may be included, these things being within the
capability of one of ordinary skill in the art.
* * * * *