__________________ Proposed System Description
We propose a two-way communication system
between motor vehicles and a centralized command and control authority,
that would utilize visible light waves as the communication medium. With
the installation of Light Emitting Diodes (LED) arrays in the center high
mount stop lights (CHMSL) of new automobiles, and the decision to install,
this more reliable technology in new traffic lights--as well as, retrofitting
existing traffic lights comes an opportunity. By setting a standard of
performance which includes technology that would allow this installed base
of optical emitters to be utilized for data exchange--in addition to its
intended function: the realization of a nationwide highway command and
control system (Intelligent Vehicle Highway System, IVHS) would be facilitated.
This would allow bi-directional (full duplex) communication between various
vehicles and a centralized network. The information that is exchanged can
be any information that improves the safety, efficiency and convenience
of the nation's roadway system.
Vehicle Modulated LED Light
The vehicle would utilize the existing light
emitting diodes, LEDs, center high mount stop light (CHMSL) as the
primary emitter or transmitter. For the receiving end, the vehicle is equipped
with two--lens coupled selective photo detector arrays, one looking forward
(driver's view) and the other looking rearward.
Traffic Light MLEDL
Like the vehicles, traffic lights also use
a LED light source, which would be similarly modulated and equipped
with zoned photo detectors.
Remote Interrogation Node
In remote or country areas, inexpensive
solar powered nodes could be installed to help complete the system. These
could communicate to the network center via radio, land-line, satellite,
daisy chained (using their own light beams), or any combination there of.
Portable Interrogation Device
Law enforcement is able to remotely interrogate
any vehicle in view, by the use of a vehicle mounted or hand held interrogating
device. The officer will be able to read and write selected, vehicle information.
RADAR (LIDAR) Feature
In addition to the CHMSL's (LED) emitter,
the vehicle will also have a front-mounted LED emitter (either red diode
LASER or orange LED running or parking light ). This in combination with
the forward-looking photo detector array (one front, one rear), the vehicle
will be able to detect objects in its path as it detects its own signal
being reflected from the object. This safety feature can be enhanced by
installing efficient retroflectors (or even reflective tape) on any object
that a vehicle may encounter, such as the sides of tractor-trailer trailers,
house trailers, farm equipment, etc.
Side-Mount Optical Transponders
There are two, inexpensive, side-mount optical
transponders on each side of the vehicle, and are made up of both,
passive retroflectors and active devices (an emitter in one and a photo
detector in the other). Their purpose is to act as efficient reflectors
for an oncoming vehicle's LIDAR, in the case of a non operating vehicle
(parked); while the active elements would be added insurance during operation.
Types of Exchanges
There are basically six types of exchanges
that will occur: data exchange, information exchange, communications, relay,
interrogation and vehicle control.
Data exchange is the most common interaction.
This is basically where the vehicle, at the network's request, uploads
its volatile and nonvolatile memory to the network. The data items being
specified by the network can be anything from the hardwired VIN # to the
date and nature of the last brake job. (See Appendix C)
Information exchange is a sort of news and
weather station. Road conditions, alternate routes, etc. for the surrounding
local, as well as, more global information, are broadcast to the appropriate
Communications such as a stranded vehicle
report or a vehicle reporting the knowledge of an emergency: its location
and the nature, etc. This can take the form of keyed-in data, a short voice
message or both.
Relay of information is where a vehicle is
stranded and is out of contact with the network. If the driver sets the
emergency switch to the "Help" mode (vehicle or health emergency), passing
vehicles' systems will be contacted and the distress message will be uploaded
to those vehicles for relay to the network, i.e., passing vehicles will
be unwitting messengers.
Interrogation Is usually initiated by law
enforcement, looking for wants and warrants, etc. It can occur at any node
as a matter of normal operation or it can be initiated from a police
vehicle or a hand held unit.
Vehicle control is where, for good and sufficient
cause, a law enforcement officer would physically stop a vehicle by remote
control by revoking its "permission to go." This control authority is only
allowed to law enforcement, and then only in a situation where there is
probable cause. This, also, is an example of the absolute need for data
encryption. (See Appendix E)
The driver interfaces with the MLEDL system
via a multi-modal interface which has for its primary design criteria,
to minimize driver distraction and to not cause unwanted shifts in driver
attention: in other words, the driver's aggregate performance is unchanged,
with or without such a system interface. The interface's output to the
driver falls into two categories: the first is related to getting the driver's
attention, and the second is informational. The alerting can be from simple
sounders (buzzer, bell, etc.) to voice messages, at selected levels of
loudness and intonation, or prerecorded family member's voices to indicate
the level of urgency, to direct the driver's attention to the situation
with a minimum of delay and confusion.
A graphical user interface, GUI, can be used
in concert with the these modes to convey a concise visual message and,
if needed, a more verbose message. This graphical presentation device can
take several forms: the Heads Up Display or HUD, for the "quick-look" alerting
type of information, as well as, driving instrumentation; and a second
display type that is more of an instrument panel display (in the dashboard)
that would be for perusal or browsing type of information, and for data
entry or menu response input (touch screen).
A subset of the informational output is information
that is not directly related to health and safety, a sort of FYI--like
road conditions, weather, etc. This informational part of the interface
can be customized to suit the user's needs or desires by prioritizing or
selectively masking the various system attributes, as long as its alteration
or masking has no effect on safety.
In the design of this or any informational
system, great care must be taken that incorrect information is never passed
to the driver. The primary reason, of course, is a matter of health and
safety, but it also relates to the driving public's confidence in the usefulness
of this, highly automated, system, especially among older drivers. A possible
scenario: when the system (network and vehicle) detects an error, the system
goes into the "Fess-Up" mode, and informs the driver that it--the network
is confused or may have made an error and should be viewed skeptically
until told otherwise. The network, in deciding whether--in fact, there
has been an error, must error on the side of safety in that judgment call.
Vehicle Host Computer
The Vehicle's Host Computer (the engine
control processor which controls all of the vehicle's functions, including
the engine control, heating/cooling system, entertainment system, etc.)
will have as one of its many tasks, the operation of the IVHS system. This
computer, with its multi-tasking operating system, is of sufficient computing
power to handle all vehicle related tasks and the IVHS operation, without
suffering overload. One of the processor's most important jobs will be
to make various, traffic related, "decisions" based on all available information
from both the vehicle and the network as quickly and accurately as possible.
It will use the most reliable and proven algorithms available: the power
and speed of Fuzzy Logic and the learning faculty of Neural Networks. The
trend (1994--95 time frame) toward powerful, reasonably priced, 32 bit
RISC processors (20 MIPS) or DSPs, will yield a cost effective solution
to the added computing power required by the IVHS system.
Because the vehicle's main computer controls
the IVHS: if someone attempted to disable the IVHS they would disable the
entire vehicle. This would happen as a result of the vehicle's computer
recognizing tampering (improper access code) or ineptitude on the tamperer's
It is important that the computing power
of the individual vehicles be utilized (pre-processing) to minimize the
processing required of the network. By distributing the IVHS processing
needs among the individual network node computers, as well as, efficiently
using the vehicles' processors, an extremely reliable and very powerful
computing entity can be established. This has the advantage of sharing
processing power with any overworked nodes, and in the event a node
fails, of taking over its tasks until it is brought back on-line.
Range detection by the following vehicle,
of the followed vehicle, is possible by using a combination of accurately
timed and phase-compared, round trip data bursts measurements. A significant
benefit of this feature is that it will better alert both drivers of the
relative closing speed and to warn of a possible rear-end collision. This
measurement technique can also be initiated by the network nodes.
Communication to the Vehicle
Once the interrogating node establishes
contact with the vehicle, it tells the vehicle to send back certain data
items. This is done in one of two ways: a command list of certain data
items and the order in which they are to be sent back is sent to the vehicle;
or one of a set of preset lists (short lists, long lists, etc.), residing
in the vehicle's computer, is selected; thus reducing transaction time.
Communication from the Vehicle
Due to the many variables such as "look
time," the number of vehicles to be handled at any given node, system bandwidth,
etc., not all vehicles can complete a transaction and must try again at
the next node. For this reason the vehicle is placed into the "unfinished
business" mode, so at the next exchange the node will ask for only that
data it missed. This is repeated until the transaction is completed.
Encryption of the data--in both directions--is
of paramount importance. Not only to prevent the circumvention of the system
and to preserve privacy, but also to prevent unauthorized control of, or
damage to, the system. This is a Hot item: a large amount of the criticism
of IVHS, will be based on privacy and autonomy questions. If the motoring
public is convinced, justifiably so, that the safeguards are real
and inviolate, they may be more favorably inclined toward the concept of
the Intelligent Vehicle Highway System.
One-way voice message (voice mail) communications
to the network can be used for reporting accidents, mishaps like a stalled
or disabled vehicle, etc.- as the vehicle is en route. No facility for
vehicle to vehicle voice communications is provided. (See Appendix E)
________________ Fail Safe
MEDL Cannot be Circumvented
A person cannot disable the MLEDL system
without causing the vehicle to eventually go into "maintenance mode." (See
Foot Note 1 ) The reason for this is, if the driver has a valid driver's
license and there are no wants or warrants outstanding, he/she is given
permission-to-go (PTG) by the network, for some interval of time (minutes
to hours). This permission is being reevaluated and renewed during each
network exchange. The network can not tell the vehicle to stop, but it
can revoke or withhold permission to go, this "fail-safe " logic of giving
permission-to-go, instead of telling the vehicle to stop (i.e., defaulting
to no-go), has the effect on unauthorized vehicle use, of eventually running
out of permission and shutting down the vehicle.
Even if the communication optics were
purposely blocked (blindfolded), the system would--after its permission-to-go
expired--go into maintenance mode and stop.
When the vehicle is headed out of an area
of frequent network nodes, into the country, for example: as it is leaving
(or entering) its permission-to-go interval is altered appropriately. Also,
Permission-to-go intervals can be shortened in certain geographical zones,
like high crime areas, or anywhere a vehicle chase is likely to occur.
To start the vehicle, the driver must insert
his/her valid driver's license "card" into the vehicle's special card reader
(part of the dash board). Upon first starting out, the vehicle will have
a grace period lasting until its first exchange, e.g., first thing in the
morning driving to work, etc.
In the event a driver is "dead-in-the-water,"
and has run out of permission-to-go time, they will have the option of
invoking time from the "emergency fund." This means that if they have less
than some number of traffic points, and are not tagged, they may drive,
on grace, until they have their first exchange with the network. At this
time, in order to retrieve their driver's license, they must present themselves
to a police traffic facility and be validated as to having had a legitimate
need: at which time they will loose their "tag" and be able to recover
their driver's license.
As a further deterrent to circumvention of
the system, at selected locations (toll plazas or traffic choke-points),
a separate method for detection and counting of vehicles will be used to
authenticate the network's count. Vehicles found to be purposely "fixed"
to avoid the system and where intent is proven, the vehicle would be confiscated.
The vehicle's system will periodically (.5
Hz) emit very short "station keeping" burst patterns, regardless of whether
the brakes are being applied or not. When the brakes are applied, the LEDs
will send the data at the appropriate duty cycle: between data bursts the
LED emitter functions as a brake light, i.e., it is at DC potential (no
The system will use various LED pulse rates
and sequences (patterns) to quickly identify the signaling mode the vehicle
is in. This allows for a very quick and simple identification of which
vehicles need attention and the importance of that exchange, without having
to interrogate each individual vehicle.
Layers of Signaling
There will be several layers of signaling
where the sending of a specific pulse pattern (repetition rate, pulse duty
cycle, pattern duty cycle) identifies the vehicle's signaling mode without
a formal data exchange, i.e., the pattern alone has sufficient information.
The first layer sends a pattern with a small
amount of imbedded data indicating only its speed. This is the signaling
mode the vehicle goes into just after a complete exchange, indicating "I've
been interrogated recently, and I don't need an exchange."
The second layer of signaling has more
imbedded data in it, like the VIN #, speed, tag status, etc., but
does not require a two-way exchange or reply. The data may be read by the
network or not. To help speed along the exchanges: the VINE is sent
in two parts, only the last n digits are broadcast, if a match occurs,
then the network asks for the remainder of the number, to delineate out
the the full or real VIN #.
The third layer requires an exchange of data
at some priority level, n.
The forth layer, a subset of the third layer,
is the "unfinished business" mode, which can have any priority, depending
on the importance of the uncollected data.
The fifth layer has the highest priority:
emergency (of which there are also several levels).
Again, these five patterns are unique and
do not require data exchange to be identified as to their purpose.
These layers operate thusly: When a vehicle
has gone long enough to need a normal data exchange (who are you? are you
tagged? etc. and here is your location, etc.) its pattern will identify
it as such. After a complete exchange, it will go to a pattern that identifies
that fact, and it will not unnecessarily tie up the next node (in the case
of traffic overload, vehicles will be prioritized). If an incomplete exchange
occurred, then the vehicle would shift to the appropriate (unfinished business)
pattern until it had completed its transaction, in subsequent exchanges.
Data Exchange Strategies
A data exchange protocol for dealing with
both large numbers of vehicles at a congested intersection or individual
vehicles, requires an adaptive nature. The avoidance of exchanging unnecessary
data is the key. If the system were screening all vehicles in a given area
or roadway, it might screen only some percentage that passed intersection
for example. These vehicles would be "marked" as having been screened and
would be skipped at the succeeding intersections. And, at intersection
"B" some percentage of the missed vehicles would be interrogated, and so
on until all vehicles have had an exchange.
One modulation method that would be used
is a multi-level encoding scheme: Quadrature Amplitude Modulation (QAM),
with m phase levels and n amplitude levels. Also, an improved version that
is more robust, called Trellis Coded Modulation (TCM). Like modems, this
system will have an ensemble of modulation methods, adaptable to the environment
as needed. Also, the programmable modulation hardware is flexible enough
to mimic any new modulation method.
Error Coding, Detection and Correction
Reliable or errorless data exchange is imperative.
The rigor exercised toward error detection and correction will have several
levels. The greatest rigor will be applied to the most important exchanges,
grading downward toward the least important. Importance being, of course,
based on driver health and safety, first and foremost. To ease any transmission
error problems, Packet Protocol will be used, such that upon successful
reception of a packet or packet groups, their unique IDs will be transmitted
back to the sending station to enable proper accounting, and to allow a
resend of lost or unrecoverable packets.
The data network is protected by an encryption
scheme based on either the NBS DES scheme or the public key approach, which
would change keys randomly and often, effectively eliminating unauthorized
access to the network.
Range measurement is possible between two
(or more) vehicles in close proximity, by exchanging accurately timed,
pseudo random data sequences. On a finite bandwidth system, better than
expected resolution is possible if time-in-transit measurements are supplemented
by carrier phase-angle measurements, with statistical averaging. However,
the resolution needed in most motor vehicle scenarios can be thought of
in terms of car-lengths (or fractions there of), not feet and inches.
Traffic Light: Stop, Caution and Go messages
are sent to the appropriate vehicles near (selective zones) the traffic
light. When the driver starts braking (with adequate deceleration), the
vehicle communicates "I'm stopping." Or a driver may not see the signal,
thus his vehicle communicates that it is moving at n MPH. In such a case,
that vehicle would be signaled in a way that would get the driver's attention,
if all else fails it might automatically take control and stop the vehicle.
(See Appendix E)
The addition of a specially collimated (slight
beam spread) low power (visible, ~650 nm) diode LASER could be installed
on the front of a vehicle, so as to be seen by approaching vehicles, would
provide a way to alert both drivers to a possible head-on collision.
Also to help prevent head-on collisions with
DWI drivers: any vehicle that has decided its driver is DWI, broadcasts
that fact to nodes and to any oncoming vehicle.
Rear-end Collision Avoidance:
Rear-end collision detection and avoidance
be feasible if the lead or target vehicle were putting on brakes and communications
between vehicles were established quickly enough. However if the lead vehicle
were stopped and not showing a brake light, there would be no warning.
This could be solved by requiring all vehicles to periodically pulse (data
burst) the brake light when stopped with no brake light showing. This is,
in fact, the strategy used and is referred to as station-keeping.
A precursor to rear-end collisions
is tail gating. There are two types of tailgating, one is in anticipation
of passing and the driver is usually attentive, and therefore less likely
to rear-end the followed vehicle. The second, and most dangerous, is the
inattentive person, who may or may not be in a hurry.
In an attempt to prevent a collision, the
system (vehicle to vehicle) will recognize dangerous following distances
and warn both drivers: the following driver in order for them to back off;
the followed driver in order that they can be on guard or take evasive
action if necessary.
Collisions While in Reverse
Vehicles backing out, in a parking lot,
or anywhere else, run a common risk of backing into another vehicle, either
as they are also backing or just passing behind another backing vehicle
. The vehicle to vehicle system would help to prevent this common, but
less catastrophic, type of collision.
Blind Spot Elimination
A problem that has plagued drivers over
the years is the "blind spot." The classic situation of the semi truck
driver not seeing the small, low-to-the-ground sports car; or the everyday
situation of a vehicle being just at that spot, between your rear-view
and side mirrors, where you can't see him in either. This would be prevented
in all cases, both vehicles, as a matter of course, would communicate
long before that spot is reached and both drivers (and their vehicles)
would be aware of the other.
When pulling onto a busy street or merging,
knowing the speed of the oncoming vehicles would allow an intelligent vehicle
to suggest the optimum time to pull into traffic. Likewise, the oncoming
traffic would be made aware of the vehicle preparing to enter traffic.
In some instances, the driver could be prevented from doing something that
is a certainty to be dangerous or cause harm to themselves or others.
(See Appendix E)
If a vehicle's headlights are not on at
the appropriate time (time of day, bad weather, etc.), the driver is alerted
by either the vehicle or the network, or the system may turn them on automatically.
Drivers of on-coming vehicles, as well as
following vehicles-- will have their high-beams dimmed by the aggrieved
vehicle sending a "request-to-dim" message. However, the offending driver
will be able to "force" the issue of his headlight status by overriding
the request (this presupposes, for purposes of safety, only).
Road conditions are broadcast: if there
is a traffic jam, construction, detour, bad weather, etc.; it would also
suggest alternate routes where possible.
A running geographical location or "fix"
is available to the Vehicle from every node it passes. Whenever the vehicle
communicates, its location can be part of the returned message. In the
case of the stranded vehicle, the stranded vehicle's last known location
is in its "help" message along with location information of the relaying
Navigation for preprogrammed short or long
trips is feasible using a combination of, network supplied, location information
and highway map data from either the network or that stored on CD ROM (option)
in the vehicle.
The approach of emergency vehicles from
the front or rear would be automatically indicated to the driver. This
transaction can occur by either the network's action or directly from the
approaching emergency vehicle's high-powered LASER emitter.
Smarter Railway Crossings
The most dangerous aspect of guarded railway
crossings is the driver's lack of certainty as to the signal's reliability:
"Is there really a train coming, and can I beat it?" Unguarded crossings
are numerous and are a very real hazard.
The MLEDL system can address the problems
of both guarded and unguarded crossings. In the case of the guarded crossing,
the driver would be given absolute information about the train's distance,
speed and time of arrival at that crossing, with recommendations as to
what course of action the driver should or should not take. As an aside:
human nature being what it is, people resist those instructions that are
without explanation. By giving all the information a person feels they
need for them to make the decision, along with a suggested course of action,
they are more apt to make the right decision, on average. However, as a
last resort the driver could be prevented from doing something that is
a certainty to be dangerous or harmful to themselves or others. (See Appendix
The unguarded crossing will become a thing
of the past: There is no technical reason why all trains could not be tied
in to the MLEDL network with vehicle transponders addressing composite
nodes (nodes that work with both motor vehicles and rail-borne vehicles).
All previously unguarded crossings would be equipped with inexpensive remote
solar powered network nodes or repeaters. The low cost remote nodes do
not necessarily have to tied into the network to fulfill their intended
Any vehicle can pick up and relay any distress
message from any vehicle stranded along side the roadway. The message can
be something as simple as a pressed emergency button, indicating either
vehicle or health trouble; or it can be a digitized voice message limited
to some short (15 sec) message, or both.
Once the message has been passed successfully
to the network, the carrying vehicle's memory is cleared of that message
by the network. A return message: "Message received," is relayed, via selected
vehicles (ones that would most likely pass the stranded vehicle), to the
distressed vehicle which terminates the sending of its distress message,
and--at the same time--turns out the red, "Help Called" message on the
console and turns on the green, "Help on The Way" message.
Automatic Toll booth ticketing and accounting,
as well as screening of vehicles, looking for stolen or wanted vehicles.
______________ Law Enforcement
Besides the communication between fixed
nodes of the network and traveling vehicles, law enforcement is able to
remotely interrogate any vehicle in view, by the use of a vehicle mounted
or hand held interrogating device. The officer will be able to read any
pertinent information from a vehicle, as well as write information to a
vehicle, to alert other authorities, e.g., in the case of a pursuit.
Legal Operation of a Motor Vehicle
The automated nature of the MLEDL system
lends itself to an improved method of restricting who legally operates
a vehicle. The vehicle will be equipped with a special card reader designed
to read the driver's specially encoded (magnetically and holographically)
driver's license. To start the vehicle, the driver must insert his/her
valid driver's license "card" into the reader (part of the dash board),
the reader will capture the card much as an automatic teller machine, ATM,
does. At the end of the trip, the card is returned to the driver if he/she
has no violations outstanding and if, in fact, the card is deemed legitimate.
If the card is not returned, for whatever reason, the driver has the option
of driving directly to the police station and taking care of the violation
and getting his license back or he/she can opt to delay taking care of
the violation and can retrieve their license which has been temporarily
rendered unusable (magnetic strip erased). Upon clearing up the violation,
their card will be reinstated by the police agency. A vehicle owner can
create a list of only those people that are authorized to drive their vehicle:
therefore the vehicle will not go for non-listed drivers. In the case of
the parking lot attendant, the owner would give "restricted permission-to-go,"
sufficient to park and retrieve the vehicle (with limited time and performance).
A driver with restricted driving privileges
or someone on work-release, can have their driving tightly monitored and
controlled by the system.
Speeding, Detection and Automatic Ticketing
When a vehicle enters a speed zone, the
speed limit is communicated to the vehicle's driver and after some time
interval (~20 seconds) its speed is read: if the vehicle's speed is above
the speed limit plus some grace, the vehicle is "tagged" and it broadcasts
to all nodes (and law enforcement vehicles) the fact that the vehicle is
in violation. Area surveillance TV cameras can record the offense for evidence.
A pursued vehicle can be stopped or put
into "maintenance mode," remotely, by the pursuing police officer
revoking the vehicle's permission-to-go .
Impaired Driver Detection and Alerting
There are two scenarios relative to DWI
detection: either the vehicle's computer deduces the quality of the driver's
performance, measured against an historical, or past performance template,
as well as, a standardized performance template; thus quantifying an index
of impairment (0 = no impairment, 9 = severely impaired). Alternatively,
the driver is evaluated as he/she passes a roadside, remote DWI monitoring
If impairment is suspected (or deduced) the
network is alerted and the vehicle in question is "tagged" (its memory
is written to) as being "suspected" of being impaired, with some quantified
value or level of suspected impairment. Above some level: probable cause
is considered to have been established and a police officer can be dispatched.
As the tagging occurs, the vehicle will broadcast its tagged status, ID
and location to the nodes it passes. The driver would be unaware of this
until he is notified to stop driving by the system or a police officer.
If the driver does not stop voluntarily, the vehicle can be put into maintenance
mode. In situations where impairment is above a level considered hazardous,
the vehicle could automatically go into maintenance mode.
Also to help prevent head-on collisions with
DWI drivers: any vehicle whose driver has been tagged as a DWI suspect,
broadcasts that fact to all nodes and to any oncoming vehicle, as well
as automatic headlight flashing, to alert pedestrians.
Hit and Run Identification
When a hit and run occurs, both vehicles
will record that fact, and each vehicle will know the ID of the other vehicle
(in the exchange prior to impact). Further, this information will be conveyed
to the next node either vehicle encounters.
When a stolen vehicle is identified, that
vehicle is "tagged" and is made to broadcasts its ID, location and the
fact that it is stolen and wanted, and it would go into maintenance mode.
Further, special hi-res surveillance TV cameras, in the area, are activated
to record (for identification and evidence) the driver of the vehicle.
Like the impaired driver detection, roadside
remote emission monitors could, similarly, communicate to the vehicle,
its emission values, and if, in fact, there was a violation. Also, the
vehicle's own engine emission control and monitoring capability is utilized
to report first hand, on the vehicle's emission quality. In this event,
the driver would be notified by the vehicle interface, and a notice of
violation would be mailed to them. This data would remain in the record
and the vehicle's memory (and continue to broadcast the tag) until the
emission violation was remedied.
Highway Traffic Data Archives
All traffic data is collected and reduced
down, or simplified, to individual vehicles and their paths, with relevant
data (time, date, etc.); and this information is stored, and can be used
(either near real-time or in retrospect) for determining who was at a specific
location in some time frame, e.g., when a crime was committed.
The MLEDL system will be capable of several
different optical modulation methods, such as PSK, FSK, QAM, TCM, etc.,
at various data rates and selected carrier frequencies. FSK has the characteristic
of rejecting congestion in a multi-signal environment (capture effect in
FM systems). In a multiple signal environment, if the stronger signal is
only 1 dB higher it is excepted with the other signals being rejected.
This rejection occurs in the limiter/IF/Detector cascade, not in the front-end
By using channelization, a significant
improvement in overcoming interference from unwanted emitters can
be achieved. As in any data exchange organization, there will be a hierarchical
structure made up of a master/slave relationship: the vehicle being the
slave with the exception of law enforcement.
______________ Emitter Technology
Emitter Technology Trends
Red LED technology is headed toward greater
efficiencies, lower costs (greater yield), and a trend toward orange colors
(complements human visual acuity), as well as, and green. Speed or bandwidth,
is also improving: 60 nsec turn-on and 40 nsec turn-off times are now being
delivered in LED CHMSL lights.
Traffic Light LED Operation
The traffic light LED colors are presently:
Red @ 660 nm, Yellow @ ~ 575 nm, Green @ 555 nm (BW ~ 100 nm). The traffic
light will either be red or green, for equal periods (on average, yellow
being only momentary). Therefore, it is necessary that the vehicle's photo
detectors be sensitive to all three colors. Depending on the expense in
both dollars and photons: either a wide, bandpass filter of 100 nm bandwidth
be used or if possible; two (or more) narrow band, bandpass filters could
be used (separate detector arrays could be used for wavelength division
Because of the amount of data that may need
to be exchanged at some intersections, all three lights (R, Y, G) might
be utilized for data on a continuous basis, i.e., when a lamp is "off"
it is modulated at a low enough duty-cycle that it is perceived as being
Traffic Light Emitter Focused on Lanes
The best signal-to-noise ratio (S/N ratio),
for both sensor and emitter, can be achieved by focusing the LEDs toward
specific areas of the traffic lanes, i.e., avoiding wasted light. By focusing
or controlling the beam spread and optimizing the directivity, the most
efficient use of the finite emitter power is achieved, without creating
LED CHMSLs have the advantage of covering
a large area at moderate intensity : as opposed to a diode LASER,
which covers very very small area with very high power. To substitute LASERs
for the LEDs would be prohibitively expensive (at this point in time).
Power Boost using Pulsed Emitters
The LED has the ability to emit relatively
large peak power, as compared to CW or average power, if pulsed for short
durations at great duty-cycles. A peak power increase of greater than 10
is possible without significant degradation to the life-span of the emitter
(LED or diode LASER).
Emitter Goodness: Incident and Reflected
The vehicle emitter will be equipped with
incident and reflected output power measuring photo detectors. This arrangement
will guard against failure of the emitter to emit at specified intensities
as well as catastrophic failure. A by-product of this feature is the detection
of any obscuration of the emitter, by something like mud, heavy fog, blowing
snow, heavy rain, vandalism or some object (the ratio of reflected to incident
light would change). In such an eventuality, the vehicle will default to
a "everybody-for-themselves" mode, and will act on its own until it finds
Either a stand-alone diode LASER emitter,
or installing an orange LED array in one or both front parking lights.
A possible approach to increased bandwidth
and wavelength diversity, is to add infrared emitters to the traffic light
triad. In addition, by using IR LEDs at some optimum wavelength (water
window), improved communications might be possible for certain forms of
_______________ Receiver Technology
The receiver end, consists of an automatic
Zoom lens; faced with protective glass bandpass filters of the correct
center frequency, bandwidth and polarization (if any); with auto focus;
auto aperture; followed by a highly sensitive and robust photo detector
array. The detector consist of an n x m array of, individually addressable,
photo detectors, the signals of which are amplified and furnished to a
bank of one or more selective limiter IF stages with demodulator. This
resulting demodulated TTL signal is then applied to a protocol decoder
(which syncs up, extracts the clock and data, and detects the correct preamble
and ID, yielding parallel data for the microcontroller, etc. The efficiency
of the detectors to extract the correct signals from all the clutter and
background interference will depend heavily on the nature of the interference.
Since the system will be monochromatic (~ 650 nm) an effort in reducing
the man made interference will payoff to a significant degree. For example,
it may be feasible to install band-reject or notch filters on or in OEM
headlights or, for that matter, any interfering light source.
Multiple photo detectors are mounted overhead
at different distances from the traffic light node. This arrangement has
the effect of segmenting the zones of reception, thus limiting the amount
of data any one detector receives.
Selective Viewpoints, fixed selective optical
masking, adaptive optical masking (LCD), barn doors, etc.
Wavelength Division Multiplexing (channelization).
Optical Bandpass Filters ahead of photo
Optical Bandreject Filters on ambient lighting
(headlights, street lighting, etc.).
Histogram analysis and margin adaptation
to multilevel demodulation.
One strategy for increasing the data throughput
an any traffic light node, is to have exchanges between vehicles approaching
the node, as well as those leaving (exchange after passing).
The data rates of this system will be limited
by the bandwidth of the LED emitters only, the optical receivers, on the
other hand, are able to receive much faster emitters (several orders of
magnitude faster). It would be desirable to establish a very high-speed
channel--Fast Channel--that could receive data from high-speed emitters.
An example of a faster emitter is the diode LASER, which could be installed
to alleviate congested intersections, where limited data rates could cause
an overload of the system and compromise safety. This "Fast Channel" would
also accommodate the inevitable faster emitters of the future.
Wavelength Shift Keying
Wavelength Shift Keying (WSK), or dispersion
shift keying (DSK) is where the emitter is capable of two disparate wavelengths,
e.g., two different wavelengths of LEDs interleaved in one array, one WL
for Mark, the other WL for Space.
The receiver would consist of two detector
arrays, each with its own very selective optical bandpass filter, viewing
the same image by virtue of a beamsplitter, through the taking lens.
A variation on this is to use both Wavelengths
as two separate channels, for greater data rates, i.e., faster transactions.
Potential Benefits, a Partial List:
Such a system implemented in an ideal world
would yield the following:
(1) DWI deterrent: The certainty that anyone
Driving While Impaired will be detected, apprehended and ultimately convicted,
should stop all but the most habitual violators.
(2) It could make car theft impossible to
all but the most sophisticated thief (hauling away or cannibalization).
The effect on speeding would be profound:
the certain knowledge of detection and apprehension--by "remote control"--should
stop all but the most foolish.
Similarly, it will eliminate the need for
high speed chases.
Remote vehicle interrogation by law enforcement.
Better head-on collision warning and avoidance.
Greatly reduced rear-end collisions.
Hit and run identification.
Improved traffic light visibility (alerting).
Reduced hazard when pulling into traffic
Improved safety at Railway crossings (guarded
Prevents the unauthorized operation of a
motor vehicle, e.g., driver with a revoked driver's license.
Better control of drivers with restricted
Improved response to approaching emergency
Breakdowns and emergencies would be easily
and swiftly reported.
Emergency voice communications.
Almost instantaneous Vehicle Location.
Improved short and long trip navigation.
Continuous information on weather and road
conditions, with suggested alternate routes.
Insuring appropriate vehicle lighting in
darkness and bad weather.
Toll booth automation and billing.
Archived traffic data can be used in
criminal investigations, and used as evidence in a trial.
RADAR (LIDAR), will detect passive objects
in the vehicles path: thus preventing collisions.
This paper discusses a reliable and inexpensive
method of communications relating to the Command, Control and Communication,
of the motor vehicle/ highway environment or some form of the IVHS. The
communication between motor vehicles and a centralized authority, via a
distributed network, is implemented as a result of the synergy of evolving
technologies. One of the several elements integral to the approach outlined,
is the effort to maximize the cost-benefits of utilizing (soon-to-be) existing
infrastructure. This infrastructure consists of both the hundreds of thousands
of LED traffic lights (soon to be installed) and the, over 150 million
vehicle, in situ computers and LED CHMSL lights. The LED is an efficient
and reliable communications device, both visually and eletro-optically,
that fits the needs for this type of localized, free-space two-way communications
milieu. To capitalize on these coming resources, there should be early
standardization of this application-specific technology.
This approach, while not perfect, have benefits
and a synergism not offered by other approaches.
Primarily, this paper's original purpose
was to introduce this communication methodology, and was not intended as
a blueprint for the Intelligent Vehicle Highway System. However, to better
discuss this technology, in the proper context, it was necessary to develop
certain themes and ideas: so there is significant discussion to that end.
As some of these themes developed, it became clear that instead of a lot
of disparate technologies being force-fit: in fact, a unified very tightly
coupled interface is possible.
In the last decade or so, technology has
brought great power to everyday life: the effect of which is vastly more
than the sum of its parts. When one begins to think of the seemingly insoluble
problems on the nations roadways--that have grown ever larger during that
same time span--have, for the most part, been past by, by technology.
With the prudent application of technology
to the full implementation of a viable IVHS, it is conceivable that the
lives lost yearly on the nations streets and highways could be reduced
by an order of magnitude or greater. Death and life altering injuries on
the highway, may one day, be an anachronism.
_______________ The Future
The future holds the promise of vastly more
efficient computers, for motor vehicles: 32 bit and 64 bit RISC processors
are just the beginning. Superconductivity and efficient electric power
sources and/or storage devices will transform the motor vehicle into a
totally different transportation entity, with its own new sets of problems
to be solved. But this transformation will be evolutionary, and effected
greatly by the form IVHS takes on today.
If haste (and other human frailties) rules
over good judgment, and we install the wrong thing at the wrong time, it
could take more than a generation to recover from such a mistake, not counting
the lives lost, in the mean time.
With the proper architecture, the IVHS will
be forward compatible well into the twenty first century.
to a Successful System, And their Possible Remedies.
In those areas that are prone to fog, special
higher powered diode LASERs could supplement existing emitters, as well
as more closely spaced nodes. When fog is too heavy the network causes
entering vehicles to default to the "Everybody-for-themselves mode." In
the event the network cannot communicate with some vehicles, the vehicle
emitter is equipped with a reflected light measuring detector that will
alert the vehicle of an obscuration, and the vehicle will default to being
on its own, while still looking for a network node. (See Technology chapter,
Rain and fog interference might be minimized
in selection of the optical wavelengths chosen for the emitters. Rain while
causing optical distortion and transmission efficiency, it will not completely
block light transmission in the near field of view.
Snow can come in several forms: drifting,
where the snow piles up obscuring the emitter or detector, or both; and
blowing snow, which has an effect somewhat similar to rain and fog, and
is similarly amenable to brute force.
Sensor Blinding by Sun angle and glare
To help alleviate the sensor blinding problem
caused by the sun and sun glare, the receiving lens will have auto-aperture.
Also, the detector will be a m x n focal-plane array of robust photo-sensors,
each possessing great dynamic range (>6 decade), which should prevent complete
blindness, i.e., it is unlikely that all photo detectors, in the array,
will be overloaded.
Limited data exchange bandwidth
The data rates of this system will be limited
by the bandwidth of the LED emitters, the optical receivers, on the other
hand, are able to receive much faster emitters (several orders of magnitude
faster). It would be desirable to establish a very high-speed channel that
could receive data from high-speed LASER emitters at congested intersections
where limited data rates might degrade the service and possibly compromise
safety. This "Fast Channel" would accommodate faster emitters of the future.
Also, a significant increase in data rates can be had by utilizing all
three colors, of the traffic light, as emitters (See also, Technology
chapter, Emitter section)
Infrequent network nodes
This can be solved by installing many inexpensive,
limited function, solar powered nodes. Some of these nodes do not require
constant attachment to the network: scheduled polling is sufficient in
most applications, with the ability to request immediate connection when
A problem with any free-space communication
system, is the problem of echoes or, in this case, reflections. Reflections
with enough intensity will be treated as any incident signal and can cause
errors relative to apparent vehicle zone position, resulting in an adverse
effect on the capacity of the network to handle all of the exchanges.
______________ A Review
of Transmission Methods
Probably the most reliable approach is the
buried wire concept. Where the wire buried in the roadway is used as an
antenna for low frequency data communication to and from the vehicle. However,
this approach has a prohibitive price tag. Because of the local nature
of the data being exchanged, the number of nodes or cells attaching to
the buried wire, would be voluminous. Also, the present "state of the Art"
of burying wires in existing pavement, seems not well understood. Therefore
the costs of installation and perpetual upkeep would be enormous.
Roadside radio (wireless) transponders is
an approach that, like the buried wire, has the advantage of reliable operation
in bad weather. However, it too suffers from high costs: by virtue of the
need to cover many very small (local) areas or cells with data of local
interest (e.g., intersections), it would require numerous transponders.
Unlike the buried wire, it would be vulnerable to interference by all those,
well understood, artifacts that effect all the other services using similar
One such artifact is unintended propagation
or coverage. It is the nature of radio waves, in an environment of high-rise
buildings, (or similar structures), to be reflected or "bounce" to other
intersections, which could cause confusion with local traffic.
The microwave transponder approach has the
advantage of being able to "see" through most bad weather; in some configurations,
it can even detect passive objects in the roadway. On the deficit
side: every vehicle (>160 million) will be a microwave emitter; in a congested
area there could be as many as several hundred microwave sources operating
at once. To make order out of this babel while maintaining reliable operations,
would require the microwave transponders, both on the vehicles and the
network nodes, to be prohibitively complex and expensive. Also, the wavelength
or band chosen will have to be a trade-off between the physical size of
the device (antenna), effectiveness in bad weather, overall effectiveness,
costs, etc. In addition, the amount of incident and reflected microwave
radiation impinging on the average driver (and children) for prolonged
periods, in various levels of congestion, may or may not be a real health
hazard, but it will surely be perceived as one. Finally, all of these microwave
emitters have the potential of wreaking havoc with the vast number of other
services using similar microwave bands.
Ultrasonics is a technology that has the
advantages of low costs, ease of installation, etc. On the deficit side:
it has very limited range, limited data exchange bandwidth, limited effectiveness
in bad weather, multi-path interference (standing waves), etc.
Visible light modulated for data exchange
is feasible: utilization of the existing (and soon to be) installed LED
light sources used in auto tail lights and traffic lights, will afford
significant savings in installed equipment costs. Photo optical sensors,
for the receiving end, are relatively inexpensive. The data rates possible
with this technology, while not the speed of microwaves, are more than
adequate for the application. Even without the installed base of LED emitters,
a cost effective system (one considerably cheaper than the equivalent microwave)
using inexpensive diode LASERs, is practical. Unlike microwaves,
light waves will cause no interference to other services. The disadvantages
of this technology is its inability to work reliably in heavy fog, very
heavy rain and a heavy snow storm. It might be noted, however, this type
of obscuration is considerably more pronounced in infrared (IR) or near
infrared (NIR) systems than in visible light systems (655 nm).
There are several types of data in the vehicle's
system: permanent (read only) hardwired data such as the Vehicle Identification
Number, VIN#, which is entered at the time of manufacture and can never
be changed; another type of data is non-volatile, which is on several levels
of security. Access to these various levels, in the form of read-only and
read/write transactions, is delineated among the appropriate authorities,
i.e., a police officer may look for wants and warrants or any restrictions,
etc., but he may not write anything, except to "tag" a vehicle for a suspected
violation. If the driver has a restricted driver's license, only DMV is
allowed to write that data into your vehicle (this data can be downloaded
to your vehicle via the network and/or written to the magnetic strip on
your driver's license. The final level of data is volatile, this is basically
temporary storage for information, messages, messages for relay, computer
program store, etc.
Permanent Types of Data Stored in Vehicles
The Vehicle Identification Number, VIN #,
is hardwired into the system at the time of manufacture and can not be
Temporary Data Stored in Vehicles
Motor Vehicle Related Data:
- State license plate number, Tag #.
- Present owner's name and address.
- Insurance data.
- History of ownership.
- Driver's restrictions (data only
related to the identified driver presently operating the vehicle).
- Outstanding wants and warrants (data
related to the vehicle, its owner, the identified driver
presently operating the vehicle, or any driver listed in the vehicle's
authorized drivers list).
- Owner's driving record (imbedded into
the vehicle's data store and in the magnetic strip of
his/her driver's license's).
- Present driver's driving record
(information read from the driver's license, by the vehicle and
temporarily held in the vehicle's memory).
- Vehicle's inspection record.
Vehicle Repair Record
All auto servicing information is logged
into vehicle's computer by authorized dealer service personnel. Non-dealer
service such as brakes, alignment, wheel balance, tires, etc., may also
be logged in, but in a different area of the data store. This information
is beneficial to disparate groups, including the owner.
Some Available, Real-Time , Vehicle Parameters
Present speed, speed history (Last n miles
or m minutes, can be specified); Brake's status: braking or not braking,
if braking, brake pressure in PSI, general braking efficiency (based on
deceleration versus brake pressure), pad condition, miles on present pads,
fluid temperature, fluid level, etc. If vehicle lighting system is in good
working order, if headlights are on, exhaust quality, and history of exhaust
quality (last n days or x weeks, as calculated from vehicle data such as
oxygen sensor history, fuel consumption history and various other engine
data). Horn: is it OK? is it blowing? Y/N (when the driver blows the horn,
it will cause an interrupt to the network and send a request to transmit,
which can be granted or at least noted by the network).
Broadcast is where, either the vehicle or
the network node, transmits data or information "for-all-to-hear." Normal
data exchanges use individual addresses to selectively communicate with
specific vehicles (likewise a vehicle requesting a certain service, would
send an address unique to that service); in broadcast mode, an address
unique to all is sent.
Center High Mount Stop Light. Sometimes
referred to as HMSL.
For our discussion, an emitter is any optical
device, LASER, LED, etc., that operates in the visible spectrum (~
500 nm to 900 nm) and is capable of transmitting data impressed on it at
applicable data rates.
This is a mode that the vehicle goes into
when its systems are not able to perform to some level of reliability.
This "failure-to-perform," can be caused by anything from a catastrophic
failure of hardware/software to severe weather, snow, ice, heavy fog, etc.
Fail-safe is choosing the right (safest)
default where a yes/no decision can go undecided. One "fail-safe," related
to the control of a vehicle, is in giving "permission-to-go" instead
of "demanding-to-stop." If a driver were to "fix" their vehicle to not
exchange data with the network, under the latter condition, all control
over the vehicle would be lost. In the former case, the vehicle would run
out of permission-to-go, go into maintenance mode and stop.
The "Fess-Up" mode is where the network
or vehicle, informs all the appropriate drivers that the network, or vehicle,
is confused or may have made an error and should be viewed skeptically
until told otherwise, in other words, it confesses.
Is a mode in which a vehicle's speed governor
is invoked and progressively reduces the vehicle's maximum achievable speed--downwardly--until
it reaches a maximum top speed of 5 MPH, which lasts for 5 minutes, and
then stops the vehicle completely. This scenario allows the driver to get
out of harm's way before the vehicle shuts down.
Interconnected central authority.
Network's communications exchange point.
A vehicle is "Tagged" by a law enforcement
officer or, in some situations, by the network, for some violation. When
one is tagged, two things happen: first the violation is written into the
vehicle's read/write nonvolatile memory; secondly, the vehicle will constantly
broadcast the fact that it is tagged and where it is and the nature of
Vehicle Identification Number
Ethics Related to Design Philosophy
This project should have certain immutable
laws (like the three laws of robotics). These laws should relate to the
driving public's health and safety, being first and foremost.
In the case of a railroad crossing, where
the driver is trying to make a decision relative to crossing or not crossing,
if he/she is given all the information they feel they need, along with
a suggested course of action, they are apt to make the right decision--on
average. However, if the driver chooses to do something that is a certainty
to be dangerous or harmful to themselves or others: as a last resort the
driver should be prevented from doing the wrong thing. This is a tough
call, the computer could make the right logical decision and still harm
someone: its a lose lose situation.
The network or vehicle should never give
the driver the wrong information. However, it inevitably will; when it
detects that it may have made an error, it defaults to the "Fess-Up mode,"
and admit it was wrong and suggests a proper course of action, and failing
that just warns the driver to beware.
Political Dimensions of IVHS
The IVHS concept, as in any centralized regulatory
entity, has enormous political dimensions and exerts first-order influences
on its final form. These influences range from the ACLU's view as a constitutional
issue relating to privacy; to MADD's view of it as a tool in their fight
against DWI. In other words, the political influences should be seen in
the context of both pro and con, relative to the acceptance and expedition
of such a major project.
It is rarely the best technical solution
that is chosen, but the solution that will fly politically--and nobody
can tell you what that is! However, the IVHS is too important a concept
to not put forth the required effort; to work diligently with great technical
rigor and political aplomb.
_______________ Some of the Issues
per sa, being neither pro nor con, are the following:
Privacy of information or access to personal
data is one of the most hotly debated issues, and one of the most abused.
Even if guarantees of security of personal information are promised, few
will believe, and, for good reason. To be successful in overcoming this
issue, an authority will have to enact and strictly adhere too, an ethic
of constitutional proportions. This will require the enforcement of need-to-know
rules that are written in law and enforcement without exception (with selected
visibility of such enforcement).
Big Brother is alive and well. The freedom
of the individual to go unmolested, either physically or emotionally, is
a freedom that will not go undefended--and should not. There are legitimate
concerns about using restrictive laws to curb the worst of us. It even
gets more involved when law-abiding citizens are restricted, "for their
own good." In other words, you should have the freedom to run the risk
of head-injury by not having to ware a safety helmet. No matter that the
public has to pay the bill (all but 1% of motorcycle head injuries); in
medical costs, public assistance, lost productivity, etc. That is the nature
of the beast, and an accommodation with this cultural milieu is in order.
What happens when the system fails? Thousands
of lives will be saved and hundreds of thousands of injuries will be prevented:
but if there is one tragic, highly publicized error of the system, that
incident, alone, will have great power. Even if the "blame" is not totally
the system's, it is that perception that can do great damage. The damage
can quickly take on real dimensions, i.e., loss of faith in the system's
reliability could have a profoundly tragic outcome.
These days restraint of trade issues are
based more and more on technicalities and endlessly linked legal precedents,
as well as on egalitarian dogma. What is good for the American public
is forgotten in the "great fight." Cooperation between government and industry
is essential, enlightened self interest for the
public-good should be the mandate, not confrontation.
Because of the wide spectrum of functions
of such a system: whose responsibility is its supervision? Is it only a
transportation entity; where does law enforcement's interests enter in
or Federal Highway, etc.?