Instrumentation for this arrangement will consist of standard, orange
traffic cones or pylons, fitted with two ultrasonic Doppler transducers--mounted
in opposition--near the top (one looks up the lane, the other looks down);
an ultrasonic distance/detection transducer (a "pinger" that looks orthogonally
to the direction of traffic flow); on top, an omnidirectional infrared
data exchange transponder; weatherproofed electronic circuitry and all
powered by a rechargeable battery mounted in the bottom, also acting as
All of the pylons are tied together, via a half-duplex (bidirectional)
IR optical link to a central or supervisory computer. The host computer
is a fast PC workstation with large disk storage and is able to process
measurement data at a rapid rate. The system has the feature of adding
workstations or servers, as the work load requires.
Rolling Alley or Gauntlet
Disposable Instrumented Pylons
Because of its remote sensing nature, the system must deduce those
parameters that would be directly measurable in the vehicle per se. Making
measurements with sufficient resolution such that the front-end steering
changes are distinct from the rear-end track of the vehicle is required.
The analysis of such data should yield a sufficient characterization of
the actual steering wheel changes, for example.
Among the parameters measured are the following:
Gross accelerations and decelerations.
Micro-accelerations and micro-decelerations:
When attempting to hold a constant speed, especially a relatively
slow speed, there is an attentiveness required to maintaining that
single speed which can be deduced. This "station-keeping," or lack there
of, has a direct relationship to the driver's condition.
Gross yaw: gross steering
Vector angle or yaw, and rate of vector swing or yawing are of
interest because they represent fine steering (minute deviation from intended
Overall lane tracking score:
Scoring the driver's overall tracking (follow the white line)
by plotting: should approximate an irregular sinusoid or smoothed trapezoid,
about a zero axis.
Directed and Non-directed Examination
When evaluating drivers for DWI in a "Rolling-Ally" lane arrangement,
there are two approaches that can be used: driver active and driver passive.
The driver active approach requires that the driver go through several
directed "problems," such as measuring how long it takes the driver to
apply his/her brakes after a stop light turns red; and then when directed
by the same light, starting off from a standing start, while being measured
for smoothness of acceleration, as well as overshooting the desired top
speed (25 MPH), or conversely, they may take an inordinately long time
to reach top speed . Also, they might be directed--by signal--to change
or shift lanes (simple slalom), hit the horn, etc., as they proceed. These
"maze" type tests could be optionally invoked near the end of the gauntlet
in those questionable cases where the computer (or the operator) needs
more definitive data. One of the drawbacks to this approach is throughput,
or the rate at which vehicles could be processed. Of course, this too could
be adaptive: as the traffic gets heavier, the number of different "problems"
Driver passive, would require no directed driver actions other than
following the lanes' path, while observing the speed limit, while being
measured for constancy of speed--cruising.
In order to tax the driver, sufficient to provoke better cues to performance:
a (standardized) curved path or "meander," or even a mild form of Slalom
might be appropriate. This type of layout would require the driver to negotiate
the changing lane geometry with some finesse, while providing an opportunity
to measure how well he/she maintains a track--as compared to others.
--DWI Driver Profile
It is important to understand the drunk or impaired driver and their
responses to various situations or stimuli. For example: An impaired driver
may drive too fast because of their removed inhibitions, etc.; or they
may drive too slowly, because of a feeling of paranoia or fear of arrest--being
over-cautious. The problem is, that there are variously different and similar
responses from an impaired driver. The trick is to catalog and categorize
them is such a way that a reliable match can be made in the real world
(with minimum false positives).
Having said all that: the first order effect will be what they do with
their vehicle, not their personality traits while impaired. The detection
of the DWI driver will depend on statistical differences between what he/she
does with their vehicle: as compared to what other impaired and unimpaired
drivers do with theirs.
___________ Evaluation Modality
The data, when measured and evaluated against known norms of performance--standardize
templates, for example, will give precise information as to the driver's
deviations from a selected set of standards.
These data will be quantified and examined statistically against statistically
valid templates of average unimpaired and impaired drivers for a consistent
grading of the driver's motor skill and coordination, performance. The
results of such comparisons will yield a numbered value indicating the
probability of impairment on some standardized rating scale. These scores
are subject to the mitigation of various things related to the season of
the year, weather, time of day, etc.
There could also be a "dynamic" template, one that is a tally of the
last n drivers' measured performance. It's a little like being graded on
the curve. One possible advantage might be in cancelling out those mitigating
The instrumented pylon is equipped with two separate Doppler transducers:
one measures the approaching vehicle's Doppler-shifted signatures and the
other measures the receding Doppler-shift as the vehicle departs. These
transduces can be switch selected or remotely commanded to operate at any
one of eight different carrier frequencies (24kHz, 30kHz, 36kHz, 42kHz,
48kHz, 54kHz, 60kHz, 66kHz). There is a third ultrasonic transducer or
"pinger" on the pylon that is a proximity or distance measuring equipment,
DME (Polaroid ®). It determines the vehicle's distance, orthogonally,
from the pylon as the vehicle first enters its zone--when it "breaks the
beam," so to speak. This information, along with similar data from all
of the other pylons', gives direct indication of how many vehicles are
in the "pipe line," and their precise instantaneous locations, as well
as their actual lengths (precision is a result of fast sampling). When
analyzing the Doppler-shift data, separating the acceleration vector data
from the yaw vector data may be helped by the pinger data, in identifying
how much of the vector sum is lateral movement. With this data and the
appropriate germane Doppler signatures, accurate profiles of performance
can be derived for each vehicle by the time the gauntlet has been run--or
The Doppler transducer's output is an analog, audio frequency signal,
that represents the "beat" difference between the ~ 50 kHz (24kHz to 66kHz)
incident ultrasonic signal and the reflected--Doppler-shifted (velocity
shifted)--signal. This signal is first band-limited by an anti-alias lowpass
filter; digitized by an inexpensive Analog to Digital Convertor, ADC, (serial
data out). This digital data is buffered and formatted, along with "pinger"
data, and sent to the USART of the IR transponder, which in turn, transmits
it (line-of-sight) to the system's computer at the appropriate time.
Central Control and Communications
Each instrumented pylon is a self-contained unit which is interchangeable
with any other similar pylon. It has the ability to establish bidirectional
(half-duplex) communication with the instrumentation computer (in the van),
via an infrared (IR) transponder mounted on top. Each pylon's transponder
is uniquely addressable (by dip switch) in a round-robin of sequentially
polled pylons. Due to the nature of the Doppler transducer's time constraints
(low beat frequencies for small changes in velocity: take longer to capture),
and the possibility of interference from adjacent transducers: no two neighboring
Doppler transducers are active at the same time. To further minimize interference,
the transducers use frequency diversity or channelization (eight different
bands: 24kHz to 66kHz, in 8 increments of 6 kHz each) , which also allows
longer on-time; thus greater resolution. The information is polled in a
fashion that facilitates this separation; in addition, it might be possible
to poll in a pseudo-random sequence, such that it will maintain proper
separation while helping to reduce sub-sample aliasing. When interrogated,
the pylon turns on its ultrasonic emitter (starts its measurement) and
simultaneously confirms this addressed command by sending back an acknowledgment
in the form of its own address, the previously sampled data (any number
of previously stored samples, held by the pylon), and after completing
this measurement it sends that data, and then shuts down and awaits its
next interrogation (the previous data is for redundancy and costs nothing).
To minimize errors, the data is block coded such that if an error occurs
that cannot be corrected, the data will be resent. Channalization may allow
the system to run (Doppler RADAR) continuously, without interference problems.
--Grand Central Station
The heart of this system is the Command, Control and Communication,
C3, or centralized control room (or van), where all of the data is received
and processed, and the tickets are handed out!
The center is run by operators (officers) who run the semiautomatic
monitoring system with minimum intervention. Their job is to setup, install
and operate the temporary installation and to oversee its, mostly automated
operation: intervening only occasionally if needed. The real heart of the
operation are the computers that are programmed to do the data reduction
and to put the decision making information at the authorities' disposal.
Data Reduction & Signal Analysis using DSPs
The data reduction will be done on fast PC workstations equipped with
ranks of 32 bit DSP coprocessor boards, along with several large hard disk
files (486/50, 586/66 DX computer). The data must be reduced fast enough
in order not to slow the traffic appreciably: this is the job of the DSP
boards, while the host computer supervises the operations and handles the
communications and control. Additional computers, or servers can be added
as needed. This flexibility (modularity) allows the same hardware that
was used in a small operation yesterday, to be part of a larger operation
When the data is first received it must be separated out and tagged
as belonging to specific identified vehicles (an operator IDs each vehicle
as it enters the pipeline, by typing in the tag number, state and vehicle
category (pick up, van, coupe, etc.). The data, once tagged, is further
separated into Doppler signature data and position or pinger data. The
Doppler data is processed by the DSP boards using FFT (fast Fourier transform)
algorithms to decipher the complex spectrum of the Doppler shifted signals
at each pylon.
When analyzing the Doppler-shift data, separating the acceleration vector
data from the yaw vector data will be helped by the pinger information,
in identifying how much of the vector sum is lateral movement and how much
is due to acceleration. As "scores" are deriving, they are segregated into
separate bins (memory), each having a particular vehicle's ID on it. These
bins are further separated into lateral and forward directions data (steering
and acceleration). Simultaneously, as the data accumulates, it is being
checked against the base line templates for a running-measure of delta
or deviation from the norm. As these numbers mature, the trends are reported,
in a continuous fashion, to the operators at Grand Central Station--via
their GUI (Graphical User Interface)--for what ever action is appropriate.
The measurement quantities can be peak to peak instantaneous deviations,
average and Root-Mean-Square (RMS), deviations; Power spectral density
Purity of Measurements
When the FFTs are performed on the Doppler data, there is an attempt
to segregate the data by direction, i.e., the lateral data from the forward
data. The purity of this separation is of some importance, but it is not
clear what the degree of purity should be. If data of some known purity
is used in a "template match" comparison against a template of similar
purity: will the answer be any different in a similar comparison if only
the purity of the data and the template changes? An interesting question.
Determining the level of driver Impairment to an equivalency of having
a blood-alcohol level considered in violation, may turn out to be relatively
_____________________ Appendix A ______________________
Four Areas of Effort in Detecting DWI
There are four discrete categories or disciplines that, when used in
concert, work toward solving the problem at hand--DWI detection. Each discipline
can be changed or improved upon without altering, either the other disciplines
or the nature of the experiment.
There is overlap or fuzzy boundaries between each, but that insures
nothing is missed.
Doppler Radar and DME pinger. And "time-to-stop" timer for directed
Data gathering, measuring and quantifying (XYZ):
ADC, IR link, FFT (DSP), quantities, etc.
Data reduction, identifying trends:
peak--peak, average, RMS, integration, differentiation, etc.
Template matching: Solving for DWI:
Correlation, Histogram, Subtraction, Summing, Standard Deviation, etc.
______________________ Appendix B ______________________
Vehicle Borne, DWI Detection and Alerting
A vehicle borne method would enlist the vehicle's own engine management
computer to monitor the driver's performance.
From an instrumentation standpoint, the vehicle borne method is superior
to the remote monitoring method: because of the direct sensing of those
things (steering wheel, fine steering; brake pressure; gas pedal position,
acceleration; etc.) that a remote monitor is attempting to deduce. The
resolution of the direct measurement approach is absolute (relatively),
as opposed to the resolution that is limited by the several constraints,
including the limited time of measurement (Doppler resolution), as well
as the finite resolution of that type of measurement.
The data derived from this, continuous measurement, would be used in
a fashion that would continually update--and compare against--an adaptive
template, one derived from the present driver's own past driving performance
(an historical template), as well as a standardized performance template
(one statically based on the population as a whole, samples of impaired
and unimpaired). Using the drivers own evolving record of performance and
continually testing for quantifiable deviations, holds great promise of
being an effective technique. However, in the unlikely event that the driver
operated the vehicle in an impaired condition a significant part of his/her
driving life: it would fail. But, there is still the possibility it would
be caught by the simultaneous testing against the standardized performance
When the vehicle's computer notes a differential in performance profile,
above some predetermined value, it can initiate a protocol of "notification
of DWI." This protocol could range from a silent alarm which could causes,
for example, the CHMSL (LED brake light) light send short data bursts that
cannot be seen (too short in duration), but can be detected by law enforcement
using simple and inexpensive detectors on their vehicles. Another alerting
method might be the use of the vehicle's integral cellular phone (which
could be circumvented by disabling the phone). It could automatically take
control of the phone and dial a special number and identify the vehicle
(prerecorded voice or cellular modem burst) by tag number.
A final and certainly controversial scheme, would be to have that vehicle's
parking lights blink at some identifying rate or pattern: signifying to
the world, its status (this will keep the lawyers busy). Case law would
have to determine what level constitutes "probable cause," in order to
have a police officer detain, interview and test the driver.
In deciding this type of thing, some Jurist will have to weight the
difference between the feelings of an outraged citizen at being publicly
embarrassed and "humiliated;" and the outrage and desolation of parents
at hearing that their child has just been hit and killed by that unchallenged
driver who was Driving While Impaired.
______________________ Appendix C ______________________
______________Testing the Design
Determining the degree of impairment of a driver at a distance is an
imponderable. First of all: can it be done? If so, then how do you do it?
After designing--on paper--a way that is deemed to be the best derivable
from the finite choices that technology has available: it must stand the
test, of--the test. There is great power in, just starting. The design
must be tested, and the results of such testing used to improve the original
design: which must be tested, and the results of such testing used to improve
the original design:
which must be tested, and the results of such testing used to improve
the original design ... and so it goes, until an optimum alley has emerged
along with a "good" experiment.
Part of the evolution of system design is testing, and the results being
fed back to alter and improve the design. The separation between research
and testing the design in this area is fuzzy, to say the least.
______________________ Appendix D ______________________
--"Rolling Alley" Standardization
The lane or "rolling alley ," configuration, what ever it turns out
to look like, should always be setup in the same arrangement or arrangements
(there may be more than one preferred way) when used as a roadside monitor.
Questions to be answered:
1.. What is a typical Gauntlet configuration: is "n" feet
in length, and has a total of "m" instrumented pylons; spaced at "k" foot
2.. The length of the alley is to be determined. 200' -->
3.. The spacing between pylons, in car lengths: .75cl -->
4.. Total number of pylons (n per side x 2 = T): 200' @
2.0cl = 16, 200' @ .75cl = 32, 350' @ 2.0cl = 22, 350' @ .75cl = 58
5.. What is the optimum speed through the gauntlet? 25MPH
6.. Staggering of the pylons (two parallel rows): what
effect will that have on the total number needed (will it reduce the number),
will it effect the required spacing between pylons, and finally, will it
alter the effectiveness of the overall system?
7.. Vehicle spacing will be important. How do you prevent
The passive driver will follow the marked lane's path while observing
the speed limit of the examination: there could be a standardized curving
path or "meander."
Time to braking where the subject driver is timed as to how long it
takes him/her to start applying brakes (as indicated by their brake light
turning on and being sensed remotely, which "stops the clock") after getting
a visual signal to do so (traffic light).
This "problem," is a great opportunity for gaining data on the driver's
1.. Smoothness of acceleration from a standing start.
2.. Overshooting the requested top speed in scenario.
3.. Conversely, a driver may take an inordinately long time to
reach this top speed.
A plot of acceleration over time would yield great information:
paying special attention to the "impulse response" of this function; it
will be either over-damped, under-damped, or normal. Normal is good!
A Slalom, or markedly curved driving course that because of its layout,
requires the driver to negotiate the changing lane geometry, and a measure
of how well the driver maintains a track--as compared to others, is a good
______________________ Appendix E ______________________
Testing & Template Construction
The building of standardized templates will require data taking of two
distinct populations, with gradations of each. The first population will
be the normal or unimpaired group. This group will be stratified in to
several categories relating to age, health or fitness criteria, visual
The second population will be the impaired group, and like the unimpaired
group will be similarly stratified. This group of people--all volunteers--will
be further segregated as to their drinking history. It should be noted,
parenthetically, that alcohol is the only impairment precursor that can
be legally used in these tests. Unfortunately, It is not a faithful representation
of the impaired population. If at all possible, all impairment precursors
should be represented in these tests, after all, the success of this research
is not purely academic--it can save countless lives or not save lives.
Under a controlled (limited access) environment these various populations
and subgroups of each, will be tested using a prototype "Roadside Monitoring
System for Impaired Drivers" (RMSFID). Preliminary data taken will be evaluated
relative to its impact to system architecture. After any modifications
to the system or the experiment: the process will continue until the design
matures, with the data taken, being of a more permanent nature (more meaningful).
There could be a "dynamic" template, one that is a tally of the last
n drivers' measured
performance. It's a little like being graded on the curve. One advantage
it may have, is to help cancel out the variables related to the season,
weather, time of day, etc.
A variation on the dynamic template is the adaptive template used in
vehicle borne systems: the data derived from the continuous measurement
of the driver's performance, would be used in a fashion that would continually
update--and compare against--an historical template of the present driver's
own performance. Using the drivers own evolving record of performance and
continually testing for quantifiable deviations, holds great hope of being
an effective technique. However, in the unlikely event the driver operated
the vehicle in an impaired condition, a significant part of their driving
life, it fails and is checked by the simultaneous testing against the standard,
or global, performance template.
______________________ Appendix F ______________________
Impairment Precursors, a List:
Impairment precursors are those mechanisms, ingested or environmental,
that work to alter or weaken one's ability to operate a motor vehicle,
to a circumscribed level of performance. The self ingested precursors fall
in several broad categories: Intoxicants, Psychotropics, hallucinogens,
some over-the-counter (OTC) medications--some with codeine or similar affecting
|| Beer, 3.2%, > 6%
|| Wine, 9% > 27%
|| Distilled Spirits
______________________ Appendix G ______________________
Motion Vector Components
Motion vector component data: each have different characteristics and
common characteristics, and it's the separation and identification of these
three components that is key to the system's usefulness.
In this system we are concerned with three basic classes of motion vector
components: longitudinal, lateral, and oblique. The longitudinal includes
the approach vector and depart vector (vehicle coming and going); the lateral
includes the front-side vector, right and left and the rear-side vector,
right and left (resulting from coarse and fine steering). The oblique is
what's left, those remaining motion components that are of sufficient magnitude,
but will not fall into either category.
There are are certain characteristics or physical laws that help in
identifying the source of a particular motion component. For example, the
rate at which the vehicle can be made to move laterally is significantly
faster than achieving the same quick or rapid movement longitudinally--accelerating
or decelerating. This can be understood if one thinks of the inertia to
be overcome--thus reducing acceleration perturbations to a relatively low
frequency function. Considerations of fine steering (that steering that
is a result of the driver's attention to small tracking errors and compensating
for them) and the differences on the front lateral and rear lateral movements.
The front end is very responsive to fine steering, as the rear wheels tend
to integrate those movements and tend to track the vector sum of the steering.
The degree to which motion component segregation is achievable, is the
result of the synergism between all of the main system components: transducer
carrier frequency, placement, directivity, relative signal strengths, signal
sampling rate; DSP processing--digital filtering, etc.
______________________ Appendix H ______________________
Ultrasonic Doppler-Shift Transducer Design
The ultrasonic transducer will operate at a frequency range of from
24kHz to 66kHz. Its beam shape or pattern should be adaptable (within a
limited range) for the application.
A single emitter could be used with multiple detectors on one pylon.
If the source were at the end of a PCB plastic tube and fed a combination,
50% power divider "T" with rotating joint assembly: each output would feed
a beam-forming feed horn. These horns are able to swivel, a limited amount,
for better aiming (for a given lane layout). Complementing this, are two
highly directional receivers (one on either side). See Drawing
The proper control of output power and receiver sensitivity is a trade-off
between achieving high quality measurements and limiting interference from
neighboring transducers. Also, maintaining good directivity is important
(narrow, at least in the x direction) by virtue of the improved motion
vector component discrimination, i.e., separating the steering induced
vehicle motion from the acceleration induced motion.
______________________ Appendix I ______________________
Outline of Proposed Research
______________________ Appendix J ______________________
Speed of Sound @ sea level: 742 MPH =13,059 inches/sec.
Doppler, incident sound wave, wavelength = 0.326480 inch, @40,000 Hz.
Doppler beat = 53.9084 Hz/MPH