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#### DOT HS-805 254

# Police Traffic Radar

## ISSUE PAPER

#### U.S. DEPARTMENT OF TRANSPORTATION National Highway Traffic Safety Administration

#### February 1980

# Highlights

-   The role of police traffic radar in traffic safety enforcement
    continues to be of critical importance, especially in view of the
    safety and fuel conservation benefits of the 55 mph speed limit and
    the requirement that all States must meet uniform national 55 mph
    compliance criteria enacted by the Congress. Police traffic radar
    provides a means of increasing enforcement effectiveness and thus
    enables police administrators to better cope with the scarcity of
    manpower resources and rapidly increasing fuel costs.

-   This report describes recent developments, and discusses activities
    sponsored by the National Highway Traffic Safety Administration. We
    have entered into an interagency agreement with the National Bureau
    of Standards (NBS) to develop performance standards for police speed
    measuring devices and we are developing a model training program for
    police officers in the use of speed measuring devices. We believe
    the products which will result from each of these efforts will help
    States to upgrade both the reliability and quality of police traffic
    radar equipment and the quality of operator training.

-   Also included in this report are the initial results of special
    tests conducted by the NBS on police traffic radar equipment
    questioned in a Judicial Hearing in Dade County, Florida. As a
    result of the decision rendered by the Eleventh Judicial Court of
    Florida, NHTSA asked NBS to conduct a series of special tests as
    part of the on-going joint NBS/NHTSA project to develop performance
    standards for various police speed measuring devices, including
    radar.

-   The NBS researchers were particularly concerned with the
    susceptibility of the radar devices to interference from CB and
    police radios, police cars\' ignition, alternator, and
    air-conditioner and heater fans. The researchers also examined
    phenomena such as: patrol speed shadowing, target speed bumping or
    batching, and possible errors due to panning, scanning, interpreting
    the cosine angle effect, and the automatic lock-on feature. NBS
    concluded, based on tests of the six devices identified in the Dade
    County hearing, that police radar which measures vehicle speeds is a
    reliable tool for police use when carefully installed and properly
    operated by skilled and knowledgeable operators.

-   This report asserts that radar is a reliable tool when properly
    installed and operated by skilled and knowledgeable operators.
    However, we recommend that States develop a comprehensive statewide
    program to establish uniform statewide standards, guidelines and
    procedures for: operator training and certification; equipment
    purchase, maintenance, testing and certification; operating
    practices; and periodic recertification of both equipment and
    operators. We believe that adoption of these basic measures should
    enable police agencies to more effectively respond to the challenges
    to traffic radar use which were raised by the Dade County Hearing.

# Background Discussion

**Issue:** The use of police traffic radar has become widespread
throughout the United States and, until recently, was widely accepted by
the courts and the general public as a reliable and accurate means of
measuring vehicle speeds. However, recent technological advances,
especially the development of \"moving radar,\" have altered the basic
concepts initially accepted by the courts. These technical innovations
have resulted in increased and highly publicized challenges to both the
reliability and accuracy of modern traffic radar devices and the
adequacy of police radar operator training.

**Discussion:** Police traffic radar has been used to detect speeding
motorists for about 30 years in this country. During that time radar
speed measuring devices have evolved from the original bulky stationary
models to the present compact and sophisticated models capable of
monitoring vehicle speeds in both stationary and moving modes. These
technological advances have greatly enhanced the mobility, efficiency
and effectiveness of police traffic radar operations. However, highway
safety and traffic law enforcement officials are now faced with a
dilemma since the same technological advances that enable increased
productivity and efficiency have resulted in increased scrutiny by the
courts. In addition, the public is now beginning to question both the
reliability and accuracy of radar devices and the adequacy of police
radar operator training.

At the present time there are no nationally recognized performance
standards for police traffic radar speed measuring devices. Further,
operator training requirements, which have traditionally been
established by each individual police agency (usually with the
assistance of the radar manufacturer), range from less than one hour to
several days. The quality of operator training often has not kept up
with the technological advances. In many cases, training has been
limited to teaching the officer how to set up, test and operate the
device. All too often, failure to provide detailed training in
recognizing and avoiding the electronic anomalies associated with modern
traffic radar devices has led police officers to believe that radar
devices are infallible.

A highly publicized Dade County, Florida evidentiary hearing regarding
the reliability and accuracy of radar illustrates the type of challenge
now being encountered. The hearing, conducted by Judge Alfred Nesbitt in
April 1979, focused on two issues. First, whether radar speed measuring
devices currently produced are reliable enough to be used as evidence;
and second, whether police officers are receiving adequate training in
the proper operation of the devices. After nine days of testimony,
during which experts from both sides were invited to give testimony,
Judge Nesbitt ruled:

.. that the reliability of the radar speed measuring devices as used in
their present modes and particularly in these cases, has not been
established beyond and to the exclusion of every reasonable doubt \... .

While the Dade County hearing has not triggered the predicted nationwide
demise of police traffic radar, it has highlighted the fact that in
certain circumstances radar does have its limitations. Subsequent court
decisions such as State of New Jersey vs. Wojtkowiak and State of Hawaii
vs. Earl W. Fedje, et al., generally have upheld the reliability and
accuracy of police traffic radar. However, the message from the courts
is clear: highway safety and law enforcement administrators must ensure
that radar operators receive adequate training, including recognition
and avoidance of the electronic anomalies associated with such devices.
Operators must be able to demonstrate their competence with the unit
under varying conditions in supervised field performance tests. In
addition, the radar manufacturing industry must implement strict quality
control measures to ensure the reliability and accuracy of their
equipment, and continue to search for ways to improve the target
identification capabilities of present radar devices.

The courts, as well as some radar critics, also have pointed out the
need for State-level policy guidance for police radar enforcement
programs. The immediate reaction to such criticism tends to be
defensive. Perhaps this is an appropriate time to review radar programs
from a constructive viewpoint. After evaluation of present programs,
highway safety and law enforcement officials should develop and
implement comprehensive policies and procedures to ensure that police
traffic radar is used properly and that traffic safety and energy
conservation goals are achieved. State-level policy guidance would
provide the added benefit of increased uniformity within a State and
encourage statewide development of standard operating procedures. This
would enhance voluntary compliance as the motorist travels through the
many jurisdictions within each State.

The National Highway Traffic Safety Administration (NHTSA) is sponsoring
two programs which should upgrade both the reliability and credibility
of police traffic radar equipment and the quality of operator training.

**Equipment:** In August 1977, before many of the above issues were
raised publicly, we entered into an interagency agreement with the
National Bureau of Standards (NBS) in the Department of Commerce to
develop performance standards for police speed measuring devices. The
NBS has inventoried all police speed measuring devices (radar and
nonradar) used in this country and is in the process of developing
comprehensive performance standards for each speed measuring device
category. The performance standards for radar devices should be
completed by June 1980. Once the standards are established, NBS will
coordinate the testing of existing devices and compile a list of those
devices meeting the standards. This qualified products list will be
published in the Federal Register.

The qualified products list will aid police administrators in making
more informed purchasing decisions. Moreover, the list will identify
those specific models which can be purchased by State and local law
enforcement agencies with Federal highway safety funds.

In addition, we asked NBS to conduct special performance tests on the
six radar devices identified in the Dade County hearing. The purpose of
this project was to test each of the six radar units to observe their
operational capability in certain operating situations or environments
that were described in the hearings The preliminary test results confirm
that the six devices produced reliable and accurate speed measurements.
However, NBS also determined that there are certain operational
situations which may lead an inattentive or untrained operator to obtain
an inaccurate reading or to associate the speed indicated on the radar
device with the wrong vehicle. NBS also points out the potential for
obtaining an erroneous reading on a target vehicle under certain
conditions when the radar unit is operated in the moving mode.
Judgemental errors may occur if police radar operators do not understand
and avoid the specific circumstances which give rise to these anomalies.

It is also clear that police administrators must ensure that radar
devices are properly maintained and periodically tested and calibrated.
Written policy defining maintenance and calibration procedures should be
established in each agency. The procedures should define the conditions
under which each device should be calibrated by a licensed technician.
As a minimum, we recommend that each radar unit be tested for
measurement accuracy annually. The written policy should specify that
accurate maintenance, repair and calibration records for each device
should be established and maintained by the agency. These records should
be available to the courts, whenever necessary, to verify the accuracy
of the device.

**Training:** In September 1978, we awarded a contract for development
of a model training program for police officers in the use of speed
measurement devices. The training program has two elements, one covering
radar speed measuring devices and one covering nonradar devices. The
overall goal of the training program is to improve the effectiveness of
speed enforcement through the proper and efficient use of speed
measurement devices. The specific objectives of the radar course are to
develop and/or improve the trainee\'s ability to:

-   Describe the association between excessive speed and accidents,
    deaths and injuries and describe the highway safety benefits of
    effective speed control

-   Describe the basic principles of radar speed measurement

-   Acquire and demonstrate basic skills in testing and operating the
    specific radar instruments

-   Identify the specific radar instruments used by the trainee\'s
    agency and describe the instruments major components and their
    functions

-   Identify and describe the laws, court rulings, regulations, policies
    and procedures affecting radar speed measurement and speed
    enforcement in general

-   Acquire and demonstrate basic skills in preparing and presenting
    records and courtroom testimony relating to radar speed measurement
    and enforcement

The radar training course is designed in a modular format to provide
maximum flexibility for the user. It is comprised of eight units, each
of which has specific performance objectives. The formal classroom
training comprises a block of 24 instruction hours. Upon successful
completion of a written exam, the trainee must undergo a minimum of 16
instruction hours of supervised field practice. After completing the
course of instruction, the trainee must be able to demonstrate his
operational (real world) competency before being certified to take
enforcement action based on radar speed evidence. Recertification of all
operators should occur within not less than one nor more than three
years.

Although this course focuses on enforcement and is intended primarily
for the police patrol officer, we recommend participation in the
training program by traffic adjudication personnel, e.g., judges,
administrative hearing officers, prosecutors, etc. Such personnel
routinely decide upon the admissibility and weight of radar speed
evidence, the strengths and weaknesses of the instruments and the
capabilities and limitations of the operators. This type of training
will provide adjudication personnel with a good working knowledge of
radar speed measurement principles and an understanding of the issues
relevant to judicial deliberations.

**Position:** The National Highway Traffic Safety Administration
believes that police traffic radar is an effective enforcement tool. The
role of police traffic radar in traffic safety enforcement continues to
be of critical importance, especially in view of the safety and fuel
conservation benefits of the 55 mph speed limit and the requirement that
all States must meet uniform national compliance criteria enacted by
Congress. Police traffic radar provides a means of increasing
enforcement effectiveness and thus enables police administrators to
better cope with the scarcity of manpower resources and rapidly
increasing fuel costs.

Highway safety and law enforcement officials should recognize the
fallacy of purchasing radar devices solely on the basis of economy
without due regard to their performance capabilities. These officials
must also recognize the importance of greatly improved operator training
and State-level policy guidance to ensure high quality and more uniform
police radar operations throughout a State. Inaction on these issues by
State and local highway safety and law enforcement officials may well
result in judicial limitations governing the use of police traffic
radar. It is essential that each State develop a comprehensive radar
speed enforcement program which, as a minimum, embraces equipment
standards, operator training, operator certification, and
policy/procedural guidance. Accordingly, each State is strongly urged
to:

-   Adopt the forthcoming NBS/NHTSA radar speed measuring device
    performance standards and require police agencies to purchase
    devices meeting those standards

-   Develop policy guidelines to ensure that radar speed measuring
    devices receive proper care and upkeep and establish clear
    procedures for programed maintenance, testing, and calibration

-   Ensure that adequate maintenance and calibration record systems
    (suitable for introduction as evidence in court) are developed and
    maintained by each agency using radar speed measuring devices

-   Adopt the NHTSA radar operator training program or its equivalent as
    the statewide minimum training standard

-   Develop a comprehensive State-level radar operator certification
    program and provide for periodic recertification (every 1-3 years)

-   Develop police radar workshops and seminars for traffic adjudication
    personnel

-   Establish State-level policy/procedural guidelines to ensure proper
    use of police traffic radar in meeting traffic safety and energy
    conservation goals and objectives.

Implementation of these minimal measures should result in significantly
improved and more uniform radar speed enforcement programs both within
the individual States and nationwide. Their implementation is necessary
to establish a sound legal foundation for radar speed evidence and to
restore public and judicial confidence in radar enforcement programs.

## Tests of Six Speed Measuring Radar Units

#### Interim Report

Submitted to

#### National Highway Traffic Safety Administration Department of Transportation Office of Driver and Pedestrian Research Washington, D.C. 20530

Submitted by

#### Law Enforcement Standards Laboratory National Bureau of Standards Washington, D.C. 20234

#### January 1980

Table of Contents

Page

Executive Summary . . . . . . . . . . . . . . . . . . . iii

1\. Introduction . . . . . . . . . . . . . . . . . . . 1

2\. Purpose . . . . . . . . . . . . . . . . . . . . . 1

3\. Procedure . . . . . . . . . . . . . . . . . . . . 1

4\. Test Results . . . . . . . . . . . . . . . . . . . 2

5\. Observations . . . . . . . . . . . . . . . . . . . 13

Appendix A\--Test Methods . . . . . . . . . . . . . . . 15

## Executive Summary

Each of the six radar models identified in hearings conducted by the
Eleventh Judicial Circuit Court of Florida were subjected to a series of
laboratory and field tests.

The tests were designed to determine whether it was possible to affect
target speed measurement under those environments or use situations
discussed in the Florida hearing.

There was no observed degradation in the performance of any of the units
arising from 1) cosine angle effect, 2) automatic lock, 3) heat build
up, 4) mirror switch aiming, and 5) high tension power wire
interference. Only one of the six units tested was affected by external
CB and none were affected by police radio transmission at distances
beyond 30 feet from the radar.

Certain of the units were affected in varying degrees by internal
electrical interference from the ignition and alternator, and
interference from air conditioner and heater fans. While transmission
from police radios in the same vehicle as the radar was found to have a
limited effect on the radar units, CB transmission in the same vehicle
affected nearly all radars.

Patrol car shadowing was found to affect all but one of the radars and
target speed bumping was observed to affect half of the units. In all
cases, the two piece radars were affected by panning the antenna beam
through the display console.

In some instances, the performance of the radar units was not degraded
by the environments or use situations described above when a target
vehicle was present.

The limited sample size precludes generalization of the test results to
an entire manufacturer product line. While there is no question that the
individual radar units that were tested are affected to varying degrees
by interference sources and certain operating conditions, it appears,
based upon observation, that the source of error can be avoided by
taking precautions in the installation of the radar unit and through
proper use by a skilled and knowledgeable operator.

### I. Introduction

This report presents the results of a series of laboratory field tests
that were conducted by the National Bureau of Standards, Law Enforcement
Standards Laboratory (LESL) to evaluate the performance of six specific
speed measuring radar units under a variety of operational and
environmental conditions.

The testing was accomplished at the request of the National Highway
Traffic Safety Administration (NHTSA) as a special project, Modification
Number 8, of the ongoing effort to develop performance standards for
speed measuring radar units under Interagency Agreement DOT-HS-7-01697.
The radar units that were tested are those identified in the hearing
conducted by the Eleventh Judicial Circuit Court of Florida; the CMI
Speedgun 6 and Speedgun 8, the Decatur Electronics MV-715, the Kustom
Signals MR-7 and MR-9, and the MPH Industries K-55.

The data presented in this report may or may not be representative of a
particular radar model since the testing was limited to only one or two
units of each model. Moreover, because of this limitation and the nature
of the field test portion of this study effort, the data cannot be used
to compare any one model with any of the others being tested.

### II. Purpose

The purpose of this project was to test each of the six models of speed
measuring radar units to observe their operational capability in certain
operating situations or environments that were described in the Florida
hearing: shadowing, batching (target speed bumping), panning error,
scanning error, cosine error and errors due to automatic lock-on
feature, heat buildup, power surge, mirror switch aiming, external
interference, and internal automobile interference. The secondary
purpose of this testing program was to collect data concerning several
basic attributes of the radar units-for use in the later development of
performance standards.

### III. Procedure

A brief description of each test procedure used during this project is
presented in appendix A. These are presented for overview purposes only,
and do not contain sufficient detail to enable the tests to be
duplicated by other laboratories.

Each speed measuring radar unit, as received, was subjected to a series
of laboratory tests to determine whether the unit conformed to the
manufacturer specifications and FCC requirements for such equipment. The
microwave radiated beam width and radar microwave oscillator frequency
were measured. These same measurements were then repeated to determine
the effects of high and low temperature and battery supply voltage
variation. In addition, the frequency of the tuning fork provided with
the unit for calibration of the device was also measured. These data
were collected for the purposes of performance standard development, and
while reported in appendix A, are not discussed in detail.

The frequency-to-speed conversion of each speed measuring radar unit,
and the POWER-ON and STANDBY-ON (Kill or Hold switch) stray reading
tests were also performed in the laboratory using the test methods
described in appendix A. The results of these tests are presented in the
next section of the report.

The remaining tests were accomplished with each speed measuring radar
unit installed in a four door sedan, typical of the type of automobiles
currently used as police vehicles (in this case, a Matador), and in a
pickup truck, or in a Pinto. A series of tests described in appendix A
were conducted to determine the presence of interference from the
vehicle alternator and ignition, and from the vehicle air
conditioner/heater fan. The interference from five watt citizen band
radios and 100 watt police radios was observed by operating such radios
installed in the vehicle with the radar unit operating, and with such
radios installed in separate vehicles that were driven toward the patrol
car to determine the distance between vehicles at which any interference
with the radar was observed. In addition, a two watt handheld portable
FM radio was operated in the patrol car with the radar unit operating.

The remaining tests were conducted on two field sites; a straight
stretch of open two lane highway 1.8 miles long (Highway 52), and a
similar secondary road (LOKOT) that was paralleled by high tension
wires. Each radar was installed in the standard four door sedan in a
position recommended by the manufacturer and the range of the radar was
measured using three different target vehicles; a compact automobile, a
standard size sedan and a recreation vehicle. Road tests also included
observations of shadowing, batching, cosine angle effect, mirror switch
aiming and high tension wire interference. These data are discussed in
the section of this report that follows.

### IV. Test Results

The results of the testing that was accomplished during this project are
summarized in table 1. In this table, and in reporting all test results,
each specific radar unit has been coded with an arbitrary designation of
A, B, C, D, E, F, or G. The test results for each operational situation
or environment as identified in the Florida hearing are presented
separately in the paragraphs that follow.

**Shadowing.** Shadowing, better identified as patrol speed shadowing,
is the tendency of a moving mode radar to use a slow moving large
vehicle rather than the ground to measure the speed of the patrol car.
The patrol speed shadowing test is described in test 16. This effect was
observed, in varying degrees, for several of the radars during testing.

-   *Radar Unit A:* Patrol speed reading went from an actual 26 mph to
    indicated 22 mph as large oil tanker passed patrol car. No other
    effects from large trucks were observed.

-   *Radar Unit B:* Large truck came to a stop 50 yards in front of
    patrol car and the patrol car reading changed from 40 to 28 mph.
    Several large trucks traveling in front of patrol car and trucks
    passing patrol car had no effect on readings.

-   *Radar Unit C:* Actual patrol speed of 25 reduced to 17 when
    following a large truck. Actual patrol speed of 34 reduced to 11 mph
    for a long time when a pickup truck passed the patrol car. Pickup
    passing patrol car decreased patrol speed reading by 10 mph and
    increased target speed reading by 10 mph.

-   *Radar Unit D:* This particular unit demonstrated very severe
    shadowing effects from moving vehicles in the vicinity of the radar.
    A 44 mph patrol speed momentarily dropped to 11 mph with a pickup
    truck 100 feet in front of patrol car. While traveling at actual
    patrol speeds of 30 to 40 mph and target speeds of 50 to 60 mph, the
    following readings were observed as the patrol car was passed by
    trucks.

  ---------------------------------- ------------------------------------
  **Patrol**                         **Target**

  12                                 80

  16                                 72

  20                                 57

  17                                 68
  ---------------------------------- ------------------------------------

-   This unit shadowed most trucks, large or small.

-   *Radar Unit E:* While traveling at patrol speed of 50 mph, shadowing
    from passing large trucks caused radar readings of:

  ---------------------------------- ------------------------------------
  **Patrol**                         **Target**

  17                                 74

  11                                 41
  ---------------------------------- ------------------------------------

-   This effect did not occur every time a truck passed. Patrol readings
    decreased momentarily several times when a passenger sedan passed
    patrol car.

-   *Radar Unit F:* While the patrol car was traveling 35 mph, readings
    of 20 patrol and 76 target were observed. Then a pickup passed the
    patrol car and pulled back into the lane. Actual patrol speed of 47
    mph dropped to 35 mph as a large truck passed patrol car. This
    happened about 20 percent of the time that trucks passed.

-   *Radar Unit G:* No effects on target readings or patrol speed
    readings of shadowing from passing large trucks were detected.

+--------------------+-------+-------+---+------+------+-------+------+
| **Table 1. Summary |       |       |   |      |      |       |      |
| of test results**  |       |       |   |      |      |       |      |
+--------------------+-------+-------+---+------+------+-------+------+
|                    | **    |       |   |      |      |       |      |
|                    | Radar |       |   |      |      |       |      |
|                    | u     |       |   |      |      |       |      |
|                    | nit** |       |   |      |      |       |      |
+--------------------+-------+-------+---+------+------+-------+------+
| **Test**           | **A** | **B** | * | *    | *    | **F** | *    |
|                    |       |       | * | *D** | *E** |       | *G** |
|                    |       |       | C |      |      |       |      |
|                    |       |       | * |      |      |       |      |
|                    |       |       | * |      |      |       |      |
+--------------------+-------+-------+---+------+------+-------+------+
| 1.  Patrol car     | S     | S     | \ | \-   | \-   | \-    | \+   |
|     shadowing      | light | light | - |      |      |       |      |
+--------------------+-------+-------+---+------+------+-------+------+
| 2.  Target speed   | \+    | S     | \ | \-   | \+   | S     | \+   |
|     bumping        |       | light | + |      |      | light |      |
+--------------------+-------+-------+---+------+------+-------+------+
| 3.  Panning error  | \-    | \-    | \ | N/A  | N/A  | \-    | \-   |
|                    |       |       | - |      |      |       |      |
+--------------------+-------+-------+---+------+------+-------+------+
| 4.  \*Scanning     | \+    | \-    | \ | \-   | \-   | \-    | \+   |
|     error          |       |       | - |      |      |       |      |
+--------------------+-------+-------+---+------+------+-------+------+
| 5.  Cosine angle   | \-\-  |       |   |      |      |       |      |
|     effect         | \-\-\ |       |   |      |      |       |      |
|                    | -\-\- |       |   |      |      |       |      |
|                    | \-\-- |       |   |      |      |       |      |
|                    | See   |       |   |      |      |       |      |
|                    | text  |       |   |      |      |       |      |
|                    | \-\-\ |       |   |      |      |       |      |
|                    | -\-\- |       |   |      |      |       |      |
|                    | \-\-- |       |   |      |      |       |      |
+--------------------+-------+-------+---+------+------+-------+------+
| 6.  Automatic lock | \-\-  |       |   |      |      |       |      |
|                    | \-\-\ |       |   |      |      |       |      |
|                    | -\-\- |       |   |      |      |       |      |
|                    | \-\-- |       |   |      |      |       |      |
|                    | See   |       |   |      |      |       |      |
|                    | text  |       |   |      |      |       |      |
|                    | \-    |       |   |      |      |       |      |
|                    | \-\-\ |       |   |      |      |       |      |
|                    | -\-\- |       |   |      |      |       |      |
|                    | \-\-- |       |   |      |      |       |      |
+--------------------+-------+-------+---+------+------+-------+------+
| 7.  Heat buildup   | \+    | \+    | \ | \+   | \+   | \+    | \+   |
|                    |       |       | + |      |      |       |      |
+--------------------+-------+-------+---+------+------+-------+------+
| 8.  Power surge    |       |       |   |      |      |       |      |
+--------------------+-------+-------+---+------+------+-------+------+
| a.  Power-on       | \-    | \-    | \ | \+   | \+   | \-    | \+   |
|                    |       |       | + |      |      |       |      |
+--------------------+-------+-------+---+------+------+-------+------+
| b.  Kill switch    | N/A   | N/A   | \ | N/A  | \+   | \+    | N/A  |
|                    |       |       | + |      |      |       |      |
+--------------------+-------+-------+---+------+------+-------+------+
| 9.  Mirror switch  | \-\-  |       |   |      |      |       |      |
|     aiming         | \-\-\ |       |   |      |      |       |      |
|                    | -\-\- |       |   |      |      |       |      |
|                    | \-\-- |       |   |      |      |       |      |
|                    | See   |       |   |      |      |       |      |
|                    | text  |       |   |      |      |       |      |
|                    | \-    |       |   |      |      |       |      |
|                    | \-\-\ |       |   |      |      |       |      |
|                    | -\-\- |       |   |      |      |       |      |
|                    | \-\-- |       |   |      |      |       |      |
+--------------------+-------+-------+---+------+------+-------+------+
| 10. External       |       |       |   |      |      |       |      |
|     interference   |       |       |   |      |      |       |      |
+--------------------+-------+-------+---+------+------+-------+------+
| a.  High tension   | \-\-  |       |   |      |      |       |      |
|     wires          | \-\-\ |       |   |      |      |       |      |
|                    | -\-\- |       |   |      |      |       |      |
|                    | \-\-- |       |   |      |      |       |      |
|                    | See   |       |   |      |      |       |      |
|                    | text  |       |   |      |      |       |      |
|                    | \-    |       |   |      |      |       |      |
|                    | \-\-\ |       |   |      |      |       |      |
|                    | -\-\- |       |   |      |      |       |      |
|                    | \-\-- |       |   |      |      |       |      |
+--------------------+-------+-------+---+------+------+-------+------+
| a.  CB radio       | \+    | \+    | \ | \+   | \+   | \-    | \+   |
|                    |       |       | + |      |      |       |      |
+--------------------+-------+-------+---+------+------+-------+------+
| b.  Police radio   | 25    | 20    | \ | \+   | \+   | 30    | \+   |
|                    | f     | f     | + |      |      | f     |      |
|                    | t\*\* | t\*\* |   |      |      | t\*\* |      |
+--------------------+-------+-------+---+------+------+-------+------+
| 11. Internal       |       |       |   |      |      |       |      |
|     interference   |       |       |   |      |      |       |      |
+--------------------+-------+-------+---+------+------+-------+------+
| a.  Ignition and   | \+    | \+    | \ | Sl   | \+   | \+    | \+   |
|     alternator     |       |       | - | ight |      |       |      |
+--------------------+-------+-------+---+------+------+-------+------+
| a.  \*Air          | \+    | \-    | \ | \-   | \-   | \+    | \+   |
|     conditioner    |       |       | - |      |      |       |      |
|     and heater     |       |       |   |      |      |       |      |
|     fans           |       |       |   |      |      |       |      |
+--------------------+-------+-------+---+------+------+-------+------+
| b.  CB radio       | \-    | \-    | \ | \-   | \+   |       | \-   |
|                    |       |       | - |      |      |       |      |
+--------------------+-------+-------+---+------+------+-------+------+
| c.  Police radio   |       |       |   |      |      |       |      |
+--------------------+-------+-------+---+------+------+-------+------+
| 1.  100 watt       | Blank | Blank | \ | Sl   | B    | Blank | \-   |
|     mobile         |       |       | + | ight | lank |       |      |
+--------------------+-------+-------+---+------+------+-------+------+
| 2.  2 watt         | Blank | Blank | \ | \+   | Sl   | Blank | B    |
|     handheld       |       |       | + |      | ight |       | lank |
+--------------------+-------+-------+---+------+------+-------+------+
| \*No effect when   |       |       |   |      |      |       |      |
| bonafide target    |       |       |   |      |      |       |      |
| was present.       |       |       |   |      |      |       |      |
+--------------------+-------+-------+---+------+------+-------+------+
| \*\*Interference   |       |       |   |      |      |       |      |
| was detected out   |       |       |   |      |      |       |      |
| to this distance.  |       |       |   |      |      |       |      |
+--------------------+-------+-------+---+------+------+-------+------+
| Notes:             | \+    | Radar |   |      |      |       |      |
|                    |       | p     |   |      |      |       |      |
|                    |       | erfor |   |      |      |       |      |
|                    |       | mance |   |      |      |       |      |
|                    |       | u     |   |      |      |       |      |
|                    |       | naffe |   |      |      |       |      |
|                    |       | cted. |   |      |      |       |      |
+--------------------+-------+-------+---+------+------+-------+------+
|                    | \-    | neg   |   |      |      |       |      |
|                    |       | ative |   |      |      |       |      |
|                    |       | e     |   |      |      |       |      |
|                    |       | ffect |   |      |      |       |      |
|                    |       | on    |   |      |      |       |      |
|                    |       | radar |   |      |      |       |      |
|                    |       | pe    |   |      |      |       |      |
|                    |       | rform |   |      |      |       |      |
|                    |       | ance. |   |      |      |       |      |
+--------------------+-------+-------+---+------+------+-------+------+
|                    | S     | Occas |   |      |      |       |      |
|                    | light | ional |   |      |      |       |      |
|                    |       | s     |   |      |      |       |      |
|                    |       | light |   |      |      |       |      |
|                    |       | e     |   |      |      |       |      |
|                    |       | ffect |   |      |      |       |      |
|                    |       | on    |   |      |      |       |      |
|                    |       | radar |   |      |      |       |      |
|                    |       | pe    |   |      |      |       |      |
|                    |       | rform |   |      |      |       |      |
|                    |       | ance. |   |      |      |       |      |
+--------------------+-------+-------+---+------+------+-------+------+
|                    | N/A   | Not   |   |      |      |       |      |
|                    |       | a     |   |      |      |       |      |
|                    |       | pplic |   |      |      |       |      |
|                    |       | able. |   |      |      |       |      |
|                    |       | Test  |   |      |      |       |      |
|                    |       | could |   |      |      |       |      |
|                    |       | not   |   |      |      |       |      |
|                    |       | be    |   |      |      |       |      |
|                    |       | perfo |   |      |      |       |      |
|                    |       | rmed. |   |      |      |       |      |
+--------------------+-------+-------+---+------+------+-------+------+
|                    | Blank | Di    |   |      |      |       |      |
|                    |       | splay |   |      |      |       |      |
|                    |       | went  |   |      |      |       |      |
|                    |       | blank |   |      |      |       |      |
|                    |       | be    |   |      |      |       |      |
|                    |       | cause |   |      |      |       |      |
|                    |       | of    |   |      |      |       |      |
|                    |       | int   |   |      |      |       |      |
|                    |       | erfer |   |      |      |       |      |
|                    |       | ence. |   |      |      |       |      |
+--------------------+-------+-------+---+------+------+-------+------+

**Batching** Batching, better identified as target speed bumping, occurs
if the target vehicle speed display varies when the patrol car changes
speed. The target speed bumping test is test 17. This effect was
observed for some of the radars during testing.

-   *Radar Unit A:* No effect on target speed readout due to
    acceleration or deceleration of patrol car.

-   *Radar Unit B:* Radar occasionally subtracted 2 to 3 mph from target
    reading when patrol car was accelerated. This was not consistent. No
    effect on deceleration.

-   *Radar Unit C:* Accelerating or decelerating patrol car had no
    effect on target readings.

-   *Radar Unit D:* Radar target speeds decreased with both acceleration
    and deceleration. Target speed decreased 3 mph when patrol speed
    suddenly increased. Target speed decreased 5 mph when patrol speed
    suddenly decreased.

-   *Radar Unit E:* No effect on target speed reading could be observed
    from accelerating or decelerating patrol car.

-   *Radar Unit F:* On rare occasions target speed readings increased or
    3 mph when speed of patrol car was increased or decreased. Mostly no
    effect.

-   *Radar Unit G:* No effect observed on target readings from sudden
    increase or decrease of patrol car speed.

**Panning Error.** Panning error occurs when the radar antenna is used
to pan through its own display. The two one-piece units cannot do this.
Using the radar in this fashion always produced an erroneous reading.
The panning error test is test number 13.

-   *Radar Unit A:* Panning antenna across radar readout console
    produced 101 mph readings.

-   *Radar Unit B:* Panning antenna across radar readout console
    produced 75 mph readings.

-   *Radar Unit C:* Panning antenna across radar readout console caused
    readings over 100 mph.

-   *Radar Unit D:* NA.

-   *Radar Unit E:* NA.

-   *Radar Unit F:* Panning antenna across radar readout console
    produced various readings.

-   *Radar Unit G:* Panning antenna across radar readout console
    produced 95 mph readings.

**Scanning Error.** Scanning errors can result when the radar operator
moves his antenna too quickly. The results obtained from testing by
positioning the radar in commonly used positions and/or pointing in
several directions are discussed below. The air conditioner/heater fan
interference test is test 13. Although erroneous readings were observed
for some of the radars during these tests, this interference was not
observed when the radars were tracking a target during operational
testing.

-   *Radar Unit A:* No effect from AC/heater fan motor or AC/heater fans
    when pointed any direction inside car.

-   *Radar Unit B:* Picked up AC/heater fan intermittently while mounted
    on dash. When heater fans were on, scanning dash with handheld
    antenna caused readings proportional to fan speed. No readings from
    fans when antenna was pointed out the side windows. Picked up fan
    readings when radar was pointed out rear window (radar held above
    back of front seat cushion).

-   *Radar Unit C:* When mounted, antenna pointed slightly downward
    towards dash with heater fans on high: Stationary Mode\--Target 52;
    Moving Mode\--Target 34, patrol 55. No readings from fans when
    antenna pointed out the side or rear windows. Antenna mounted
    outside rear passenger window slightly aimed at dash with fans on,
    picked up readings 24 to 52 mph in stationary mode.

-   *Radar Unit D:* Handheld radar pointed at dash, picked up AC/heater
    fans. No effect from fans, no readings when pointed out the side or
    rear windows.

-   *Radar Unit E:* Handheld radar antenna pointed at dash picked up
    readings from AC/heater fans. This unit seemed to pick up the fans
    extremely easy when antenna was aimed forward but not mounted on
    dash mount. No readings when antenna was aimed out the side or rear
    windows.

-   *Radar Unit F:* No fan readings when unit was dash mounted. When
    radar antenna is pointed at dash, radar picks up fan readings. No
    speed readings when antenna is pointed out the side or rear windows.

-   *Radar Unit G:* Scanning dash with radar antenna did not pick up
    AC/heater fans. No readings when antenna was pointed out the side or
    rear windows with all fans on.

**Cosine Angle Effect.** The cosine error, better named cosine angle
effect, was closely observed during the testing for this effect is
present any time that the radar and the target vehicle are not heading
directly toward each other. The speed the radar displays when in the
stationary mode, is equal to the actual speed times the cosine of the
angle between the direction of travel of the target vehicle and the
radius vector from the radar to the target vehicle. Radar training
manuals advise radar operators not to use radars where the direction of
travel is greater than 12 degrees from the center of the radar beam.
Twelve degrees produces a 2.2 percent reduction in the speed displayed.
When operating in the moving mode and assuming center beam tracking, the
radar has the same cosine angle effect in the patrol speed reading as in
the target speed reading. The cosine angle effect was not the subject of
a separate test, but was instead observed during field testing. No
erroneous readings were noted during these tests due to the cosine angle
effect.

**Automatic Lock:** The advantages and disadvantages of the automatic
lock feature were also observed. The advantage is in enabling the
officer to automatically obtain a speed on the display console using a
preset threshold value. The disadvantages far outweigh this advantage.
The primary one is that it prevents the radar operator from obtaining a
tracking history, i.e., what the vehicle being tracked does after it is
detected traveling over the speed limit. Also, the radar may
automatically lock-on to a stray abnormal reading which only appeared
momentarily due to an unobserved interference source. Another
disadvantage is that use of the automatic lock feature makes it almost
impossible to compare the patrol car speed with its radar measured
counterpart to insure that the two agree at the time the display is
locked in or at times of possible interference such as that brought on
by patrol speed shadowing. Again, there was no separate test to observe
the use of the automatic lock feature. Instead, its use was evaluated
during the field tests.

**Heat Buildup:** None of the radar units were significantly affected by
heat buildup, as tested by exposure to high temperatures. For example,
the worst condition which was experienced by test radar unit D, produced
a change in speed of only 0.019 miles per hour.

-   *Radar Unit A:* At a temperature of 60° C, the microwave frequency
    changed from 10522.1 to 10516.3 MHZ and the radiated power, 85 mW
    was unchanged.

-   *Radar Unit B:* At a temperature of 60° C, the microwave frequency
    changed from 10533.1 to 10523.7 MHZ and the radiated power, 134 mW,
    was unchanged.

-   *Radar Unit C:* At a temperature of 60° C, the microwave frequency
    changed from 10520.6 to 10516.2 MHZ and the radiated power, 120 mW,
    was unchanged.

-   *Radar Unit D:* At a temperature of 60° C, the microwave frequency
    changed from 10539.1 to 10519.3 MHZ and the radiated power 34.25 mW,
    was down 0.6 dB.

-   *Radar Unit E:* At a temperature of 60° C, the microwave frequency
    changed from 10544.5 to 10541.6 MHZ and the radiated power, 39.2 mW,
    was down 0.2 dB.

-   *Radar Unit F:* At a temperature of 60° C, the microwave frequency
    changed from 10550.9 to 10546.2 MHZ and the radiated power, 26.3 mW,
    was down 0.3 dB.

-   *Radar Unit G:* At a temperature of 60° C, the microwave frequency
    changed from 10512.1 to 10513.0 MHZ and the radiated power, 56 mW,
    was unchanged.

**Power Surge:** The power surge that occurs when the radar unit is
first switched on or when a HOLD or KILL SWITCH is activated did not
affect any of the six types of radar. The hold or kill switch is a
device that is used to inhibit, or \"kill\", radar transmissions,
usually for the purpose of identifying a specific target at a range well
within the radar capability. The use of this switch allows the radar to
be operational and \"ready to go\" but not actually transmitting. No
false readings were noted during these tests, which are described in
test 10. The results are given in table 2 below.

**Mirror Switch Aiming:** Mirror switch aiming also was not a problem.
This method of operation, which permits the operator to place the radar
in his rear window looking backwards while he looks frontwards, did not
produce any erroneous readings. Obviously, a non-attentive operator
could misread the radar speed portrayed in his mirror, but he would
discover his mistake when he reread the displayed speed when writing the
traffic citation. These tests were run during field testing.

**External Interference:** Each radar unit was evaluated under field
operating conditions as described in test 11 to determine the operating
range for three different size targets. These data are presented in
table 3. While most of these tests were conducted on Highway 52, as
noted in the table, several additional tests were conducted on a
secondary road, identified as the LOKOT location, which is paralleled by
high tension wires. Theoretically, defective high tension wires may
affect radar speed measuring devices by causing stray readings or by
decreasing the sensitivity of the radar and thereby reducing its range
of operation. However, no stray readings were noted in testing near and
under high tension wires for any of the models tested.

  ----------- --------------- ---------- ---------- --------- --------------- ---------
  **Table 2.                                                                  
  Power-On                                                                    
  and Kill                                                                    
  Switch test                                                                 
  data**                                                                      

              **Power-on**               **Kill                               
                                         switch**                             

  **Radar**   **Stat.\        **Mov.\    **Stat.\   **Mov.\   **Stray\        **Auto\
              (sec) (1)**     (sec)      (sec)**    (sec)**   readings(4)**   lock\
                              (1)**                                           (2)**

  A           1.24            25.13      No Kill              7 mph           No
                                         Switch                               

                                                                              

  B           2.28            2.42       No Kill              00/100          No
                                         Switch                               

  C           2.04            2.10       1.16       1.66      100 mph         No

  D           2.13            6.86       No Kill              01 mph          No
                                         Switch                               

  E           1.26            2.10       0.23       5.04      Note 3          No

  F           2.50            2.57       Note 3     Note 3    100 mph         No

  G           0.63            25.38      No Kill              None            No
                                         Switch                               

  Note 1.     Elapsed time                                                    
              until valid                                                     
              radar speed                                                     
              readings.                                                       

  Note 2.     Did radar unit                                                  
              lock on to a                                                    
              false reading?                                                  

  Note 3.     Last previous                                                   
              valid reading                                                   
              displayed                                                       
              momentarily.                                                    

  Note 4.     No stray                                                        
              readings were                                                   
              recorded when                                                   
              the radar was                                                   
              switched on in                                                  
              the absence of                                                  
              simulated                                                       
              patrol/target                                                   
              speed signal.                                                   
  ----------- --------------- ---------- ---------- --------- --------------- ---------

### Table 3 Presents \"Radar Range Test Data.\"

  -------------- ------------ ------------- ------------ ----------- ---------- ----------- -----------
  **Table 3.                                                                                
  Radar Range                                                                               
  Test Data**                                                                               

  **Location**   **Patrol\    **Target\     **Closing\   **Target\   **Radar\   **Range\    **Notes**
                 speed\       speed\        time\        car**       type**     (miles)**   
                 (mph)**      (mph)**       (sec)**                                         

  HWY52          51\          53\           12.5\        veh #1\     A\         0.36\       
                 44\          49\           10.0\        \"\         \"\        0.26\       
                 32           68            11.0         \"          \"         0.3         

  HWY52          40\          50\           39.5\        veh #2\     A\         0.99\       1\
                 52\          44\           19.7\        \"\         \"\        0.53\       .\
                 40           58            24.7         \"          \"         0.67        .

  HWY52          40\          39\           3.2\         veh #3\     A\*\       0.07\       
                 41\          50\           7.\          \"\         \"\        0.18\       
                 40\          37\           4.4\         \"\         \"\        0.09\       
                 41           54            9            \"          \"         0.24        

  \*This radar                                                                              
  unit is the                                                                               
  same                                                                                      
  manufacturer                                                                              
  model as that                                                                             
  used in the                                                                               
  tests above                                                                               
  with target                                                                               
  vehicles 1 and                                                                            
  2.                                                                                        

  HWY52          43\          51\           11\          veh #1\     B\         0.29\       
                 54\          51\           13.8\        \"\         \"\        0.40\       
                 43           48            14.2         \"          \"         0.36        

  HWY52          43\          48\           41.2\        veh. #2\    B\         1.04\       
                 53           43            40.5         \"          \"         1.08        

  HWY52          43\          51\           17.8\        veh #3\     B\         0.46\       .\
                 41\          45\           6.3\         \"\         \"\        0.15\       .\
                 47\          50\           20.0\        \"\         \"\        0.54\       .\
                 44\          46\           7.4\         \"\         \"\        0.18\       .\
                 40\          37\           37.6\        \"\         \"\        0.8\        2\
                 42           49            9            \"          \"         0.23        .

  HWY52          31\          43\           12.8\        veh #1\     C\         0.26\       
                 43\          48\           10.2\        \"\         \"\        0.26\       
                 43           55            14           \"          \"         0.38        

  HWY52          47\          39\           46\          veh #2\     C\         1.1\        
                 45           36            51           \"          \"         1.1         

  HWY52          36\          49\           18.5\        veh #3\     C\         0.44\       
                 32           48            25           \"          \"         0.56        

  HWY52          41\          27\           30.8\        veh #3\     C\         0.58\       
                 41\          47\           26\          \"\         \"\        0.64\       
                 41\          58\           16\          \"\         \"\        0.44\       
                 41           50            27           \"          \"         0.68        

  LOKOT          38\          37\           18\          veh #2\     C\         0.38\       3\
                 37           42            20           \"          \"         0.44        .

  LOKOT          37\          28\           16\          veh #3\     C\         0.29\       3\
                 38           47            8            \"          \"         0.19        .

  HWY52          42\          53\           12\          veh #1\     D\         0.32\       
                 42           45            4            \"          \"         0.1         

  HWY52          43\          60\           32.1\        veh #2\     D\         0.92\       
                 44           48            16           \"          \"         0.41        

  HWY52          41\          43\           6.4\         veh #3\     D\         0.15\       4\
                 44\          50\           11.8\        \"\         \"\        0.31\       .\
                 42\          44\           4.2\         \"\         \"\        0.1\        .\
                 43\          55\           8.6\         \"\         \"\        0.23\       .\
                 41\          35\           3.0\         \"\         \"\        0.06\       5\
                 41           52            4.6          \"          \"         0.12        .

  LOKOT          37\          51\           7.4\         veh #1\     E\         0.18\       3\
                 42\          51\           17.8\        \"\         \"\        0.46\       .\
                 45           50            20.8         \"          \"         0.55        .

  HWY52          42\          58\           18.4\        veh #2\     E\         0.51\       
                 42\          52\           8.5\         \"\         \"\        0.22\       
                 40\          44\           6.5\         \"\         \"\        0.15\       
                 42\          52\           8.5\         \"\         \"\        0.22\       
                 43           44            8.1          \"          \"         0.20        

  HWY52          51\          48\           5.0\         veh #3\     E\         0.14\       
                 41\          39\           4.0\         \"\         \"\        0.09\       
                 40\          38\           4.0\         \"\         \"\        0.09\       
                 32\          37\           23.7\        \"\         \"\        0.45\       
                 23           43            17.6         \"          \"         0.32        

  HWY52          41\          49\           4.4\         veh #3\     E\         0.11\       
                 41\          45\           4.0\         \"\         \"\        0.1\        
                 42           37            3.4          \"          \"         0.075       

                                                                                            

  HWY52          42\          51\           2.0\         veh #1\     F\         0.05\       
                 32\          44\           6.0\         \"\         \"\        0.06\       
                 38\          48\           3.5\         \"\         \"\        0.08\       
                 41           44            2.0          \"          \"         0.05        

  HWY52          46\          65\           4.0\         veh #2\     F\         0.12\       
                 52\          50\           6.0\         \"\         \"\        0.17\       
                 42\          35\           1.0\         \"\         \"\        0.02\       
                 42           47            5.6          \"          \"         0.14        

  HWY52          41\          50\           2.0\         veh #3\     F\         0.05\       
                 43\          50\           2.0\         \"\         \"\        0.05\       
                 50           50            2.2          \"          \"         0.06        

  HWY52          50\          47\           6.2\         veh #1\     G\         0.17\       
                 45\          43\           5.2\         \"\         \"\        0.13\       
                 50\          48\           12.2\        \"\         \"\        0.33\       
                 45           66            12.0         \"          \"         0.37        

  HWY52          40\          45\           16.0\        veh #2\     G\         0.38\       
                 50           52            12.0         \"          \"         0.34        

  HWY52          41\          49\           7.0\         veh #3\     G\         0.17\       .\
                 41\          33\           5.6\         \"\         \"\        0.12\       6\
                 39\          35\           15.6\        \"\         \"\        0.32\       7\
                 40           50            6.0          \"          \"         0.15        .

  LOKOT          42\          47\           11.5\        veh #3\     G\         0.28\       3\
                 44\          43\           13\          \"\         \"\        0.3\        .\
                 37           51            18.2         \"          \"         0.44        .

  LOKOT          sta\         46\           47.2\        veh #3\     G\         0.6\        8\
                 sta          48            42.0         \"          \"         0.56        9

  Vehicle #1                  Two door Ford                                                 
                              Thunderbird                                                   

  Vehicle #2                  Augmented                                                     
                              Winnebago                                                     
                              Mobile Home                                                   

  Vehicle #3                  Two door Ford                                                 
                              Pinto                                                         

  NOTES:                                                                                    

  1\.            Police car                                                                 
                 between                                                                    
                 target and                                                                 
                 radar                                                                      
                 vehicle.                                                                   

  2\.            Picked up                                                                  
                 and then                                                                   
                 lost target                                                                
                 for several                                                                
                 seconds.                                                                   
                 Picked up                                                                  
                 another car                                                                
                 way behind                                                                 
                 Pinto.                                                                     

  3\.            Farm road                                                                  
                 paralleled                                                                 
                 part way by                                                                
                 high tension                                                               
                 power lines                                                                
                 on large                                                                   
                 metal poles.                                                               

  4\.            Also                                                                       
                 measured                                                                   
                 large truck                                                                
                 in                                                                         
                 stationary                                                                 
                 mode: 40                                                                   
                 seconds at                                                                 
                 53 mph,                                                                    
                 range 0.6                                                                  
                 miles.                                                                     

  5\.            Tracked and                                                                
                 displayed                                                                  
                 truck going                                                                
                 57 mph long                                                                
                 before                                                                     
                 tracking                                                                   
                 Pinto. Truck                                                               
                 was well                                                                   
                 behind                                                                     
                 Pinto.                                                                     

  6\.            Picked up                                                                  
                 truck at 57                                                                
                 mph, 100 yds                                                               
                 behind                                                                     
                 Pinto.                                                                     

  7\.            Picked up                                                                  
                 and then                                                                   
                 lost target                                                                
                 for several                                                                
                 seconds.                                                                   

  8\.            Patrol                                                                     
                 vehicle                                                                    
                 stationary                                                                 
                 under high                                                                 
                 tension                                                                    
                 power lines.                                                               

  9\.            Patrol                                                                     
                 vehicle                                                                    
                 stationary                                                                 
                 100 yards                                                                  
                 away from                                                                  
                 high tension                                                               
                 power lines.                                                               
  -------------- ------------ ------------- ------------ ----------- ---------- ----------- -----------

Four of the radars did not display false readings due to external police
radio transmission and only one radar was affected by external CB
operation. Radar operations in the vicinity of CB radio transmissions
are described in test 14. Radar operations near mobile police radio
transmissions are described in test 15.

-   *Radar Unit A:* No effect from CB radio mounted in a pickup three
    feet from the patrol car. Intermittent speed readings from the 100
    watt transmitter mounted in a car up to 25 feet from patrol car.

-   *Radar Unit B:* No effect from CB radio mounted in a pickup three
    feet from the patrol car. With radar mounted on dash of the patrol
    car, the 100 watt transmitter caused readings of 45 and 31 mph up to
    20 feet away.

-   *Radar Unit C:* No effect from CB radio mounted in a pickup three
    feet from the patrol car. No effect from the 100 watt transmitter.

-   *Radar Unit D:* No effect from CB radio mounted in a pickup three
    feet from the patrol car. No effect from the 100 watt transmitter.

-   *Radar Unit E:* No effect from the CB radio mounted in a pickup
    three feet from the patrol car. No effect from the 100 watt
    transmitter.

-   *Radar Unit F:* CB radio mounted in a pickup caused readings of 60
    to 70 mph at distances up to 175 feet from patrol car. The 100 watt
    transmitter operated in the compact vehicle caused radar readings at
    5 feet from the left rear of the patrol vehicle to 30 feet to the
    right of the patrol vehicle.

-   *Radar Unit G:* No effect from CB radio mounted in a pickup five
    feet from patrol car. 100 watt transmitter in adjacent car caused no
    target readings. The radar picked up the correct reading on a
    passing target car and whistling into the 100 watt transmitter
    microphone did not effect reading. As the target went out of range,
    target reading jumped to 44 and 55 for a few seconds.

**Internal Interference:** Radars were operated in their usual
configuration in a patrol car and the electrical interference due to the
patrol car ignition system, alternator, and air conditioner and heater
fan motors was investigated. These tests are described in tests 12 and
13. Some of the radar units displayed readings when the air conditioner
and heater fans were operated with no radar target present, and one type
displayed a reading during the ignition and alternator testing.

-   *Radar Unit A:* No interference caused by patrol car or pickup
    alternator or ignition.

-   *Radar Unit B:* No interference caused by patrol car or pickup
    alternator or ignition.

-   *Radar Unit C:* With radar mounted in pickup, erratic patrol speed
    readings from engine alternator and/or ignition in the moving mode.
    Extreme interference from heater fan motor (electrical) in the
    moving mode.

-   *Radar Unit D:* No interference caused by patrol car or pickup
    alternator or ignition.

-   *Radar Unit E:* No interference caused by patrol car or pickup
    alternator or ignition.

-   *Radar Unit P:* No interference caused by patrol car or pickup
    alternator or ignition.

-   *Radar Unit G:* No interference caused by patrol car or pickup
    alternator or ignition.

When a CB radio was installed in the same vehicle as the radar unit,
operating from the same battery, several of the radar units were subject
to interference during CB transmission.

-   *Radar Unit A:* When the CB radio and the radar were mounted in the
    same truck and connected to the same battery, interference from the
    CB radio was evident. Interference from the tone whistled into the
    microphone caused speed readings to be displayed.

-   *Radar Unit B:* When radar and CB radio were connected to same
    battery in truck readings were observed on radar target readout
    depending on frequency of CB audio.

-   *Radar Unit C:* Radar and CB radio connected to same battery In-
    pickup caused readings in stationary mode.

-   *Radar Unit D:* Interference from CB radio when radar and CB radio
    were powered by same battery supply.

-   *Radar Unit E:* No effect when radio and radar were both connected
    to the same battery in the pickup.

-   *Radar Unit F:* Not tested because the unit was found extremely
    sensitive to external CB transmission.

-   *Radar Unit G:* Radar and CB radio connected to same battery
    in-pickup caused readings on radar target display. Under these
    conditions, radar picked up correct reading on passing target car
    and whistling in CB microphone had no effect on correct reading
    until target was out of range.

Radar operations in the same vehicle with police radio transmissions are
described in test 15. Most of the radars blanked when this took place,
but one was not affected and two others were affected. Blanking prevents
the operator from using a false reading.

-   *Radar Unit A:* 100 watt transmitter blanked out target reading but
    not patrol reading. Handheld 2 watt radio sometimes blanked out
    target reading but did not effect correct reading.

-   *Radar Unit B:* 100 watt transmitter blanked out patrol and
    target-readings. Handheld 2 watt radio blanked out target
    occasionally.

-   *Radar Unit C:* No effect on readings from either the 100 watt
    transmitter or the handheld 2 watt radio.

-   *Radar Unit D:* 100 watt transmitter had no effect on large targets
    or strong signals, but it boosted target speeds as much as 20 mph on
    distant weak signals or small targets. Handheld 2 watt radio had no
    effect on readings.

-   *Radar Unit E:* 100 watt transmitter blanked out both readings.
    Handheld 2 watt radio had no effect on strong targets, but on
    several weak targets, the radar displays dimmed and indicated random
    erroneous readings.

-   *Radar Unit F:* 100 watt transmitter blanked out readings on weak
    signals but had no effect on strong signals. Handheld 2 watt radio
    blanked out readings on weak signals but had no effect on strong
    signals.

-   *Radar Unit G:* 100 watt transmitter caused increases or decreases
    of 10 mph in target speed readings intermittently. Handheld 2 watt
    radio blanked out weak distant targets but had no effect on strong
    signals.

### 5. OBSERVATIONS

The manner in which each of the six models of speed measuring units
evaluated performs under the eleven situations or environments mentioned
in the Florida hearing vary from one model to another. As noted earlier,
the limited sample size precludes any attempt to generalize the results
to the entire product line of any of the manufacturers, however, for
those units that were tested there was no observed degradation of
performance arising from 1) cosine angle effect, 2) automatic lock, 3)
heat buildup, 4) mirror switch aiming, and 5) high tension power wire
interference. With one exception, external CB radio transmission did not
interfere with the performance of the radar, and 100 watt police radios
transmission did not interfere with the radar units at distances beyond
30 feet from the vehicle in which the radar was operated.

Electrical interference from the ignition and alternator affected two of
the radar units, and interference from air conditioner and heater fans
was found to affect four of the radars. Operating a CB radio in the same
vehicle as the radar interfered with all but one of the radar units that
were tested, while only two of the units were affected by transmission
from a police radio in the same vehicle. Only one radar unit was
affected by transmission from a 2 watt handheld unit in the vehicle with
the radar.

All of the radar units but one displayed erroneous readings from patrol
car shadowing, and three were affected to some degree by target speed
bumping. All of the two piece radars were affected by panning the beam
through the display console and all but two of the units were subject to
scanning error.

It appears that those circumstances described above that result in
target speed measurement error can be avoided by taking precaution in
the installation of the radar units and through proper use by a skilled
and knowledgeable operator. The scope of the project, however, was
limited to testing devices under assumed operating conditions, and did
not examine in depth the effect of varying the individual conditions.
The observations offered below are based instead upon knowledge and
experience gained in the process of designing and conducting the tests.
We have not performed studies to investigate the extent to which an
operator in taking the conditions into account can avoid the problems
cited.

1.  Two-piece radars can produce erroneous readings when an antenna is
    panned through the display console. The radar should not be mounted
    with the display console in the antenna beam.

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12. Air conditioner and heater fans and alternator or ignition noise can
    interfere with the radar when no bona fide radar target is present.
    The radar antenna should be mounted so that it is not pointing
    toward air conditioner or heater fans. If possible, the antenna
    should be mounted outside of the patrol vehicle.

13. Patrol speed shadowing can occur during moving mode radar
    operations. Operators should be aware of this and recognize its
    symptoms, should know its cause and that its effect can best be
    detected by checking the radar patrol car speed with the patrol car
    speedometer.

14. Target speed bumping can occur during moving mode radar operations.
    Operators should know what it is and how it occurs and that its
    effect can be avoided by maintaining constant speed when making
    radar speed measurements.

15. The cosine angle effect can occur during stationary radar operation
    when the target is off axis within the antenna beam. Operators
    should understand the cosine angle effect and recognize when it is
    occurring.

16. Transmission from 100 watt FM police radios, both external to and
    within the patrol vehicle, can cause the radar display to blank or
    produce erroneous readings. operators should be aware of this and
    not transmit on police radios while using the radar.

17. Internal transmission from CB radios can produce erroneous readings.
    Operators should be aware of this and not transmit on CB radios
    while using the radar.

18. The use of the automatic lock feature may result in wrong target
    identification. operators should be aware of this and not use the
    automatic lock feature, but instead use the manual lock feature and
    then only when they have observed sufficient \"tracking history\' to
    insure that the correct target vehicle is being tracked.

19. When two or more vehicles are in the radar beam, it can be difficult
    to select the correct target. Operators should continue radar
    tracking until the proper target is positively identified; it may be
    necessary to wait until the vehicles pass by the patrol car and the
    one being tracked no longer registers a speed on the display
    console.

### Appendix A. Test Methods

#### 1. Antenna Pattern Half-Power Beam Width Test

The radar unit was positioned on the base of a vertical test stand in an
anechoic chamber with the antenna pointed upwards towards the
omnidirectional isotropic probe of a field intensity meter. The probe
was rigidly mounted 50 to 100 cm (20 to 40 in) above the face of the
radar antenna. The position of the radar was adjusted on the base until
the probe was in the center of the antenna beam (on boresight) and the
field intensity recorded. The radar unit was then moved to the right and
to the left of the probe until half-power was indicated on the meter.
The distance between the half-power points was then measured. The
distance was again measured while moving the radar on a path
perpendicular to the previous direction. The distances between the
half-power readings are used to calculate the half-power beam width
using the following equation to correct for change in radius distance,

A (degrees) = 2f\' ArcTan (b/r)

where f\' is a correction factor from the half-power beam width
calculation, b is the perpendicular distance from boresight to the
half-power point, and r is the distance from the front of the antenna at
which the boresight power density was measured. The results of these
tests are given in table A-1.

#### 2. Radar Microwave Oscillator Frequency Test

A small horn antenna was connected to a microwave (µw) frequency
counter. The counter was placed in the anechoic chamber where it was
convenient to point the radar unit towards the counter pick-up horn. The
results of these tests are given in table A-2.

#### 3. Microwave Radiated Power Test

The radar unit was positioned in an anechoic chamber with a field
intensity meter having an isotropic probe located on boresight in the
far-field (50 to 100 cm). The antenna half-power beam width was then
measured as described in test 1 and the approximate total radiated
power, P, was calculated from the equation:

P (mW) = 8f\'b^2^S

where f\' and b are defined in test 1 above and S is the power density
at the distance (radius) at which the half-power point is measured. The
results of these tests are given in table A-3.

#### 4. Battery Supply Voltage Variation Test

The radar unit was connected through an ammeter to a variable voltage
power supply adjusted to 13.6 volts and the supply current recorded.
Then the µw radiated power, µw oscillator frequency, and tuning fork
tests were performed in the anechoic chamber as described above. The
supply voltage was increased 20% to 16.3 volts and the above
measurements repeated and recorded. Then the supply voltage was reduced
20% to 10.8 volts and the measurements repeated. Any variation from the
nominal values at room temperature were noted for µw power, µw frequency
or tuning fork calibration. The results of these tests are given in
tables A-2 and A-3.

#### 5. Low Temperature Test

The radar unit was cooled to 30 degrees Celsius in an environmental
chamber and kept at this temperature for thirty minutes. Then the unit
was removed from the cooling chamber and the µw power, µw frequency, and
supply current were measured in the anechoic chamber, and the radar
tuning fork test was performed. Any variation from, the nominal values
at room temperature were noted for µw power, µw frequency and tuning
fork calibration. The results of these tests are given in tables A-2 and
A-3.

#### 6. High Temperature Test

The radar unit was heated to 60 degrees Celsius in an environmental
chamber and kept at this temperature for thirty minutes. Then the unit
was removed from the oven and the µw power, µw frequency, and supply
current were measured in the anechoic chamber, and the radar tuning fork
test was performed. Any variation from the nominal values at room
temperature were noted for µw power, µw frequency and tuning fork
calibration. The results of these tests are given in tables A-2 and A-3.

#### 7. Low Voltage Failure or Alarm Test

The radar unit was connected to a variable voltage power supply as
described in 4. above, and the supply voltage slowly lowered while
performing the radar tuning fork test until the radar either ceased to
work properly or else emitted an audio or visual warning alarm. The mode
of response (failure or alarm) and supply voltage were recorded. The
results of these tests are given in table A-4.

#### 8. Tuning Fork Frequency Test

The X-axis of an X-Y oscilloscope was connected to an audio frequency
synthesizer and the Y-axis connected to a microphone. The tuning fork
was then struck on a non-metallic surface and held in front of the
microphone while the frequency synthesizer was adjusted until a
stationary circular lissajous pattern appeared on the oscilloscope. The
adjusted synthesizer frequency is the same as the tuning fork frequency.
The results of these tests are given in table A-5.

#### 9. Radar Tuning Fork Test

The radar frequency and frequency-to-speed conversion was verified by
striking a tuning fork against a non-metallic surface and then holding
it in front of the radar antenna, noting whether the speed indicated by
the radar agreed with the tuning fork. Moving mode radar was checked
using the two tuning fork method. The first tuning fork was rung as
above, then a second higher frequency tuning fork was struck and also
held in front of the antenna. The radar must display a patrol vehicle
speed based upon the frequency of the lower fork and a target vehicle
speed based upon the difference of the frequencies of the two forks.

#### 10. POWER-ON and STANDBY-ON (Kill or Hold Switch) Stray Reading Test

This test was set up in the laboratory on a simulated range consisting
of a test stand with a single-side band modulator driven by a radar
maintenance test device capable of simulating both the patrol vehicle
speed and the target vehicle speed. The radar was positioned on the test
stand adjacent to a start/stop clock and a television camera and video
recorder were used to record the radar and the clock readings. The start
switch on the clock was connected in conjunction with the radar POWER-ON
switch or the radar KILL switch. Moving mode conditions (usually patrol
speed 55, target speed 66 mph) were set up on the simulator, the clock
set to zero, and the video recorder started. Then the POWER-ON switch or
the KILL switch was turned on, starting the clock and activating the
radar unit. All radar display readings and the clock times were recorded
on the video tape. Then the video tape was reviewed in slow motion to
determine the readings and times which had appeared on the display. The
test was repeated in the AUTO-LOCK mode to determine whether or not the
unit would accept a stray reading, if present, and lock on to it. The
POWER-ON and KILL switch test was then performed during the road test in
actual operating conditions.

#### 11. Range Test

Range tests were conducted in two locations. One was a straight stretch
of open two lane highway 1.8 miles long. Each radar unit, in turn, was
properly mounted in or on a Matador four door sedan patrol car. Three
types of vehicles were used for the target vehicle, an augmented
Winnabego recreation vehicle for a large target, a Thunderbird two door
sedan for a medium target, and a Pinto two door hatchback for a small
target. The patrol car and target car approached each other at a
constant rate of speed. As soon as the target vehicle was detected by
the radar, a stop watch was activated and then stopped when the two
vehicles were directly opposite each other. The constant speeds of both
vehicles were read on the radar unit readout and verified with each
speedometer via two-way radio. The radar range was calculated from the
equation:

Distance = (Target speed + patrol speed)×(closing time)/3600

Similar tests were run on a 1.3 mile straight farm road paralleled part
way by high tension wires on large metal poles immediately adjacent to
the roadway.

#### 12. Alternator and Ignition Interference Test

The car engine was started and turned off several times and the engine
was slowly accelerated with the radar on and the antenna pointed out
through the windshield or mounted in a dash mounting with no radar
target available. The test was accomplished in a four door sedan and in
a pickup truck.

#### 13. Air Conditioner/Heater Fan Interference Test

The radar was operated while mounted on the dash or window, either
inside or outside the vehicle, with the heater or air conditioning fans
turned off or on at various speeds with no radar target available. When
interference was detected, the fan motor was turned off noting whether
the interference stopped immediately or gradually decreased in speed as
the fan speed decreased. If the interference stopped immediately, the
interference was considered to be electrical. If not, it was considered
to be generated by the fan blades. The radar antenna was then handheld
and aimed at the dash and panned with the fans operating at various
speeds. Tests for fan interference were also made with the antenna aimed
out the driver\'s window, the rear window and the passenger side window.

#### 14. Citizens Band Radio Interference Test

A five watt CB radio and a base-loaded mobile roof mount antenna were
mounted in a pickup truck which was then parked five feet away from the
patrol car equipped with a handheld or mounted radar gun. Tests were
performed by keying and whistling into the CB microphone at various
frequencies. If interference was detected, the tests were repeated as
the truck approached the patrol vehicle from 150 feet away. The tests
were also performed with the CB radio and the radar in the same vehicle
powered by the same battery.

#### 15. Police Radio Interference Test

A 100 watt police communications FM radio and a 5/8 wavelength 2.5 dB
gain roof mount antenna were mounted in a two door compact car five feet
away from the patrol car which was equipped with a handheld or mounted
radar. With the radar on, tests were performed by whistling into the
police radio microphone at various frequencies. The tests were repeated
as the compact approached the patrol vehicle. The same tests were
performed with the police radio and the radar in the same vehicle
powered by the same battery. A 2 watt handheld FM radio was also
operated in the patrol car with the radar to check for interference. A
blanked radar display from radio interference was not considered an
erroneous reading.

#### 16. Moving Mode Patrol Speed Shadowing Test

This was a road test to examine the tendency of a moving mode radar unit
to adopt the difference speed between a slower moving truck and the
patrol car for calculations of patrol speed. This tendency would result
in an erroneous target speed reading. The test consisted of approaching
slower moving trucks from behind while continuously comparing the radar
patrol speed reading with the patrol car speedometer. If patrol speed
shadowing occurs, the radar patrol speed will read the closing speed
with the truck rather than with the ground. The same effect may occur
when a large truck overtakes and passes the patrol car.

#### 17. Moving Mode Target Speed Bumping (Batching) Test

Moving Mode target speed bumping occurs if the radar target vehicle
speed varies when the radar car changes speed while operating in the
moving mode. This effect may occur if a radar unit does not read and
update the patrol speed and the target speed simultaneously. This test
was conducted by rapidly accelerating and decelerating the patrol car
and observing the target vehicle speed while doing so.

  ------------------------- --------- ------- ------- ------- ------- ------- -------
  **Table A-1. Radar beam                                                     
  width.**                                                                    

                            **Radar                                           
                            unit**                                            

                            **A**     **B**   **C**   **D**   **E**   **F**   **G**

  Half-power beam width\    13.3      20.4    17.5    18.8    18.6    24.6    14.3
  (degrees)                                                                   

                                                                              
  ------------------------- --------- ------- ------- ------- ------- ------- -------

  ------------------- --------- --------- --------- --------- --------- --------- ---------
  **Table A-2.                                                                    
  Oscillator                                                                      
  frequency                                                                       
  measurements.**                                                                 

                      **Radar                                                     
                      Unit**                                                      

  **Test condition/\  **A**     **B**     **C**     **D**     **E**     **F**     **G**
  measured                                                                        
  parameter**                                                                     

  Ambient             10522.1   10533.1   10520.6   10539.1   10544.5   10550.9   10517.1
  temperature\                                                                    
  13.6 volts (MHZ)                                                                

  30°C & 13.6v (delta +11.4     +9.2      +3.8      +7.7      +5.5      +5.1      +9.4
  MHZ)                                                                            

  60°C & 13.6v (delta -5.8      -9.4      -4.4      -19.8     -2.9      -4.7      -4.1
  MHz)                                                                            

  Ambient & 10.9v     -0.7      -0.6      -2.3      -0.1      -0.1      0         +0.l
  (delta MHz)                                                                     

  Ambient & 16.3v     0         0.1       0         -0.1      +0.l      0         0
  (delta MHz)                                                                     
  ------------------- --------- --------- --------- --------- --------- --------- ---------

  ----------------------- --------- ------- ------- ------- ------- ------- --------
  **Table A-3. Radiation                                                    
  power measurements.**                                                     

                          **Radar                                           
                          unit**                                            

  **Test                  **A**     **B**   **C**   **D**   **E**   **F**   **G**
  condition/measured\                                                       
  parameter**                                                               

  Ambient temperature\    85        134     120\*   34.25   39.2    26.3    56
  13.6 volts (mW)                                                           

  -30°C & 13.6v (delta    0 dB      0       0       0       0       0.2 dB  0
  mW)                                                                       

  60°C & 13.6v (delta mW) \-\--     0       0       0.6 dB  -0.2 dB 0.3 dB  0

  Ambient & 10.9v (delta  -0.35 dB  0       0       0       0       0       -0.87 dB
  mW)                                                                       

  Ambient & 16.3v ( mW)   0         0       0       0       0       0       0

  Ambient supply\         1220      54      1060    250     260     290     1170
  current (ma)                                                              

  \*Lensed Antenna:                                                         
  measured with horn and                                                    
  power meter.                                                              
  ----------------------- --------- ------- ------- ------- ------- ------- --------

  ---------------- --------- ---------- ---------- ------- --------- ---------- ---------
  **Table A-4. Low                                                              
  voltage test                                                                  
  data.**                                                                       

                   **Radar                                                      
                   unit**                                                       

                   **A**     **B**      **C**      **D**   **E**     **F**      **G**

  Battery voltage  11.9      6.0        7.6        10.2    10.3      6.6        11.9
  (V)                                                                           

  Description      Warning   Blanks\*   Blanks\*   Fails   Warning   Blanks\*   Warning

  \*Retains                                                                     
  correct reading.                                                              
  ---------------- --------- ---------- ---------- ------- --------- ---------- ---------

  -------------- ---------------- ----------------------- ----------------
  Table A-5.                                              
  Tuning fork                                             
  accuracy test                                           
  data.                                                   

                 **Speed**                                

  **Radar\       **Labeled**      **Calculated\***        **Frequency\
  unit**                                                  (Hz)**

  A              35               35.51                   1114.6

  A              65               65.54                   2057.0

  B              35               34.91                   1095.7

  B              50               50.01                   1569.6

  B              80               78.92                   2477.0

  C              40               40.01                   1255.7

  C              90               89.98                   2824.0

  D              \--              \-\-\-\--               \-\-\-\-\--

  E              35               34.80                   1092.3

  E              88               87.62                   2750.0

  F              50               49.87                   1565.2

  G              35               35.53                   1115.0

  G              65               65.53                   2056.7

  \*Radar unit                                            
  displays do                                             
  not show                                                
  fractions of a                                          
  mile per hour.                                          
  -------------- ---------------- ----------------------- ----------------

\*U.S. GOVERNMENT PRINTING OFFICE: 1980- 311-586:18