NBSIR 75-960 C

The Police Patrol Car:

State of the Art

.

R. G. Massey

Institute for Applied Technology

National Bureau of Standards

November 1975

Final

Prepared by

Law Enforcement Standards Laboratory

National Bureau of Standards

Prepared for National Institute of Law Enforcement and Criminal Justice

Law Enforcement Assistance Administration

U.S. Department of Justice

NBSIR 75-960

THE POLICE PATROL CAR:

STATE OF THE ART

R. G. Massey

Institute for Applied Technology

National Bureau of Standards

November 1975

Final

Prepared by

Law Enforcement Standards Laboratory

National Bureau of Standards

Prepared for National Institute of Law Enforcement and Criminal Justice

Law Enforcement Assistance Administration

U.S. Department of Justice

U.S. DEPARTMENT OF COMMERCE, Rogers C.B. Morton, Secretary

James A. Baker, III, Under Secretary

Dr. Betsy Ancker-Johnson, Assistant Secretary for Science and Technology

NATIONAL BUREAU OF STANDARDS, Ernest Ambler. Acting Director

ACKNOWLEDGMENTS

This report was prepared by the Law Enforcement Standards

Laboratory of the National Bureau of Standards under the

direction of Jared J. Collard, Acting Manager, Police Vehicle

Program, and Jacob J. Diamond, Chief of LESL. Appreciation is

extended to the National Association of Fleet Administrators,

the Ford Motor Company, the General Motors Corporation, the

Chrysler Corporation, the American Motors Company and other

contributors for their assistance. The preparation of this

report was sponsored by the National Institute of Law

Enforcement and Criminal Justice (NILECJ), Lester D. Shubin,

Program Manager for Standards. It is also being printed by

NILECJ under the designation LESP-RPT-0403 . 00

i i

The Police Patrol Car: State of the Art

CONTENTS

Page

1 . Introducti on 1 2. Background 1 3. Functions of a Patrol Car 2

3.1 General Functions 2

3.1.1 Transportation of Personnel .... 2

3.1.2 Equipment Carrier 2

3.1.3 Protecti on 2 3.1.4 Office Space 2

3.1.5 Temporary Detention Facility ... 3

3.1.6 Deterrence and Presence 3

3.2 Duty Functi ons . 3

3.2.1 Urban Patrol 3

3.2.2 Highway or Freeway Patrol 3

3.2.3 Moving Surveillance 4

3.2.4 Undercover Operations 4

3.2.5 Utility or General Transportation . 4

3.2.6 Other 4

3.3 Discussion ..... 4

4. Vehicle Performance Characteristics 6

4.1 Speed and Acceleration 6

4.2 Handling and Maneuverability 7

4.3 Brake Reliability 7 4.4 Durability and Maintainability 8

4.5 Human Factors 8

4.6 Vehicle Size . 9

4.7 Engine Performance 10

5. Vehicle Subsystem Problems that Affect Police

Mission Performance 10

5.1 Brake System 10

5.2 Suspension System 12

5.3 Engi ne 13

5.4 Cooling System 16

5.5 Body and Interior 17

5.6 Tires 18

5.6.1 Bias Ply 20

5.6.2 Radial Ply 21

5.6.3 Bias Belted 22

i i i
5.7 Electrical System . . 22

5.8 Steering 23

5.9 Emission Control System 24

6. Patrol Car Acquisition 2 5 6.1 Design Specifications 26

6.2 Performance Specifications 27

6.3 Acquisition Procedures 28

6.4 Life Cycle Costs 29

7. Vehicle Performance Testing 30

8. Vehicles in Current Use as Patrol Cars .... 31

9. Hew Developments 41

9.1 Pollution Control 41

9.1.1 Stratified Charge Engine 41

9.1.2 Wankel Rotary Enaine 41

9.1.3 Stirling Cycle Enaine 44

9.1.4 Diesel Enaine 44

9.1.5 Gas Turbine 44

9.1.6 Electric Engine 44

9.1.7 Intake Valve Throttled Enqine ... 48

9.2 Fuel Efficiency " 48

9.3 Brakes 48

9.4 m ires 52

9.5 Safety Regulations 52

9.6 Special Police Vehicle .... 53

10. Vehicle Fleet Management 53

11. Summary 54

Appendix—References 56

iv
THE POLICE PATROL CAR: STATE OF THE ART

]. INTRODUCTION

One of the major items of equipment used in law enforcement

is the patrol car; an estimated 65,000 automobiles costing in

the range of $200,000,000 are purchased each year.

To learn more about the problems of police vehicles, the

National Institute of Law Enforcement and Criminal Justice, in

1972, requested the Law Enforcement Standards Laboratory (LESL)

to initiate a study of the current state of the art of vehicles

used as police patrol cars. The objective of this study was to

develop an understanding of the vehicles, the accessories and

the options that are available for police patrol; the

activities for which patrol cars are used by law enforcement

agencies; and, the problems encountered by the users in

performing the required activities with the available vehicles.

The study points to areas where vehicle performance is not

meeting law enforcement requirements and could be improved

within the present state of the art.

A list of publications referred to in the text or consulted

by the author in producing this study is provided in the

bibliography. In addition, numerous officers and officials of

police departments across the country contributed their views

and experiences. In particular, mention should be made of the

departments of the City of Los Angeles; City of New York;

Ladue, Missouri; Montgomery County, Maryland; St. Louis County,

Missouri; California Highway Patrol, and Michigan and Maryland

State Police.

2. BACKGROUND

It has been stated that, "Law Enforcement is simply the

protection of life and property and the preservation of the

peace. This is the purpose of all police departments, and the

best way to achieve this purpose is through the use of an

effective and efficient patrol and patrol plan."[l]* The major

functions of patrol forces are: (1) to prevent and deter

crime, and to apprehend criminals; (2) to respond to calls for

assistance from the public; and, (3) to regulate traffic.

*The numbers in brackets indicate references listed at the

end of the report.

1 .
To accomplish these tasks, patrol forces employ all forms

of transportation: walking, bicycles, horses, motor scooters,

motorcycles, automobiles, water craft, and aircraft. Of these,

the automobile is by far the most important. Various types are

used, including trucks, vans, and station wagons, but the

passenger car used for patrol purposes represents the largest

category of vehicles, in terms of total numbers.

3. FUNCTIONS OF A PATROL CAR

3.1 General Functions

The police patrol car performs a variety of specialized

functions during the course of day-to-day operations. A

listing of these functions would include [2]:

3.1.1 Transportation of Personnel

The basic function of any vehicle is transportation. For

police patrol, this includes transporting patrol officers in

performance of their duties, as well as transporting prisoners

and other personnel . 3.1.2 Equipment Carrier

A vehicle may carry a variety of equipment to assist the

patrolman in performing his duties. Equipment may include

radio communications equipment, spotlights, weapons, fire

extinguishers, gas masks, shovels, flares, clothing, protective

equipment, and innumerable other items as required.

3.1.3 Protection

The patrol car provides protection not only from the

elements, but also occasionally against armed adversaries and

irate citizens.

3.1.4 Office Space

The patrol car functions as a patrolman's office for

completing forms, writing reports, and interviewing people.

When used by a supervisor or commander, the patrol car may be a tactical or operational headquarters.

2.
3.1.5 Temporary Detention Facility

The patrol car is routinely used to detain arrested persons

until they can be transferred to normal detention facilities.

3.1.6 Deterrence and Presence

The well-marked police car is considered by some to be a deterrent to potential violators. It provides visible notice

of the presence of police officers to those seeking help. The

patrol unit may represent to many citizens the most familiar

and common contact with their police force and their local

government

3.2 Duty Functions

Another method of describing patrol car functions is based

on the type of patrol duty. This widely used approach analyzes

the performance characteristics needed in a vehicle for each

general type of patrol. One authority [3] has defined the

vehicles as follows:

3.2.1 Urban Patrol

The vehicle used in urban areas is expected to idle or

travel at speeds of 15-30 mph (25-50 km/h)* much of the time

and to have good acceleration in the 30-50 mph (50-80 km/h)

range. Excellent handling and stability are required to permit

safe maneuvering in traffic. Because of the slower, controlled

traffic in dense urban areas, a high top speed capability of

110 mph (160 km/h) or more is usually not required. To some

departments, an intermediate-size vehicle is considered

acceptabl e

3.2.2 Highway or Freeway Patrol

Highway patrol requires cruising routinely at 50-60 mph

(80-95 km/h) or more on high speed roads. All the

characteristics of the urban patrol vehicle are desirable,

except that the vehicle may be larger and heavier and high

speed performance is required. Rapid acceleration is required

between 70 and 100 mph (115 and 160 km/h) with a top speed of

about 120 mph (195 km/h).

Standard International (SI) metric equivalents appear in

parentheses throughout the report as a convenience to the reader.

Speeds in ki 1 ometers-per-hour have been rounded to the nearest

zero or 5, since all mi 1 es-per-hour speeds are approximations.

3.
3.2.3 Moving Surveillance

Moving surveillance involves keeping a person, usually

traveling in a car, under surveillance without being observed.

A vehicle similar to that for urban patrol in handling,

braking, and speed characteristics is desirable. The

appearance of these unmarked vehicles must allow them to blend

into the general vehicle population. Pursuit capabilities are

required, since these unmarked vehicles are frequently used for

traffic enforcement.

3.2.4 Undercover Operations

An undercover vehicle is used in vice control, narcotics

investigation, and other activities where the officer's

identity must be concealed. For this service, vehicles must

blend with the vehicle population in which they are used and

may vary from high-priced luxury automobiles to compacts. Any

special police equipment, other than a heavy duty suspension

might compromise the identity of the police officer and his

mission.

3.2.5 Utility or General Transportation

Automobiles equipped with lower performance engines are

adequate for administrative and general transportation.

Vehicles without special equipment that can meet a wide range

of general transportation functions reduce procurement and

maintenance costs. Compact vehicles are being used more

frequently for this function in order to conserve gasoline.

3.2.6 Other

Vehicles used for field supervision, special communications

functions, logistical supply, emergency rescue and other duties

which might be considered supplementary to basic patrol

functions should be equipped, as a minimum, with a heavy-duty

suspension. This description of patrol cars includes compact

cars. Sub-compact cars are also being used for one-man patrols

in a few areas.

3.3 Discussion

While the patrolman is unlikely to think of the individual

functions of his vehicle in the above terms, each of them has

to be considered by those responsible for the management of a motorized patrol force. The extent to which the vehicle used
in patrol satisfies these requirements has an impact on patrol

effectiveness. There are at present only limited data which

one can use as a basis for assessing vehicle performance

relative to these functional uses.

The general functional approach to describing a patrol car

should be more helpful than the duty approach in any study

designed to improve patrol car performance. Functional needs

should be defined for a particular agency's duties and

considered when ordering patrol cars. Basically, this approach

should define the acceptable levels of performance required to

meet the patrol's functional needs, such as: who and how many

are to be transported; in what kind of environment will the

vehicle operate (urban, rural, or mixed); for what will the

vehicle be used (pursuit, traffic, surveillance, etc); how much

and what equipment needs to be mounted, and where; how much and

what kind of space is needed for office-type activities; and so

on. With a clear definition of these requirements, the vehicle

manufacturer may then be able to select and bid on his most

suitable model and the procuring agency will have some basis

upon which to evaluate the various offerings.

The duty approach, on the other hand, represents the

current general practice of defining patrol car requirements in

terms of design characteristics, equipment options and

accessories thought necessary to accomplish specific types of

patrols. This design approach has been pursued cooperatively

by the producers and the users to modify essentially standard

passenger cars to achieve better acceleration, speed, braking,

handling, and stability than is exhibited by a similar

passenger car.

Neither the duty nor the design approach is adequate by

itself, since one focuses on the man and the other on the

machine. Both approaches must be considered. The environment

in which the patrol functions must also be recognized as an important part of the total system.

Economic considerations are not addressed by either

approach. While cost may not be of direct concern to the

individual patrolman using the vehicle, it is important to the

fleet administrator, to the responsible governmental body, and

ultimately to the tax-paying citizen.

5.
4. VEHICLE PERFORMANCE CHARACTERISTICS

It is difficult to think of any police activity where

vehicles are not involved in some manner. If these activities

are limited to those assigned to patrol cars, the activities

can be grouped into crime patrol, traffic management and a general activity that might be called "community service" or

just "service."

Crime patrol can be described as looking for criminal

activity in progress, deterring criminal activity by being

present, and responding to calls for assistance when criminal

acts have been or are being committed. An analysis of radio

dispatcher calls in one large city indicated that about 16

percent of the patrol activity was crime related [2].

Traffic management is concerned primarily with the

enforcement of traffic laws, with promoting the free flow of

traffic, and with traffic accident investigation.

Service includes all the other activities, generally not

crime related, such as responding to fires, assistance to

citizens, search or rescue operations, and medical emergencies.

These activities may occur in a variety of environments, from

the wide-open spaces of the interstate highway system to the

congested narrow streets of urban areas.

These three main activities can be analyzed to determine

what performance characteristics are required in patrol cars to

carry out the law enforcement mission.

4.1 Speed and Acceleration

Pursuit of offenders requires a high speed capability.

Highway patrols normally specify a top speed of 125 mph (200

km/h) or more for their patrol cars. Pursuit speeds rarely

reach 100 mph (160 km/h) in urban areas due to road design, or

the presence of other traffic or pedestrians.

Cruising speeds also differ widely between highway and

urban areas. Highway vehicles normally cruise near the speed

limit, 50 to 60 mph (80 to 95 km/h), while urban vehicles

usually cruise at 25 to 30 mph (40 to 50 km/h), or less.
Acceleration is important in pursuit situations. Vehicles

must be brought to pursuit speed as quickly as possible from

either a cruise speed or a full stop. For the highway patrol

car, the most important acceleration range is from 50-60 mph

(80-95 km/h) to 100-110 mph (160-175 km/h). In the city, the

important acceleration range is from about 25-30 mph (40-50

km/h) to 50-60 mph (80-95 km/h).

"High speed pursuit" is a patrol car activity which

requires acceleration, speed, good handling, maneuverability,

and stopping capability. The elimination of a high speed

pursuit capability from a patrol car would appear to have a significant effect on patrol car design and maintenance. For

instance, smaller engines might be feasible. Theoretically,

smaller engines have advantages such as better gasoline

mileage, less heat in the engine compartment along with its

detrimental effects on components, less air pollution, and

lower vehicle weight.

4.2 Handling and Maneuverability

While the standard passenger car usually provides adequate

handling and maneuverability for general transportation, patrol

cars must be capable of performance nearly like that of a sports car. The patrol car needs to maintain a steady,

controllable posture on any type of road surface at high speeds

and be easily maneuverable in such situations as turns at high

speeds or on congested streets. Standard passenger cars will

nose-down in a high speed stop, or "lean" to the outside in a turn, thus limiting the vehicle speed. These characteristics

should be minimized in a patrol car. Favorable handling

characteristics have been variously labeled "good cornering

ability," " roadabi 1 i ty

, " and "maneuverability."

4.3 Brake Reliability

Brake reliability is important in any vehicle, but it is

particularly critical in patrol cars which are routinely

subjected to continuous stop and go or high speed driving under

a wide range of environmental conditions. Data from the

Bunten/Klaus survey [4] indicate that reliability is decreased

substantially by frequent brake applications.

7.
4.4 Durability and Maintainability

Maintenance is an important factor in patrol car

performance. Oil and coolant changes, tune-ups and other types

of routine maintenance are usually performed at shorter

intervals than on normal-use vehicles. To maximize in-use

time, maintenance and repairs should be easy to accomplish.

The extent to which a patrol car continues to function with

only routine maintenance is important to the accomplishment of

police missions, as well as to the cost of police operations.

Vehicles that break down frequently or fail to provide the

expected service are a serious handicap to a police department.

4.5 Human Factors

Police patrol performance can be affected in numerous ways

when "human factors" are not given adequate consideration;

these include seating, location of instrumentation, interior

space, door sizes, personal safety devices, etc.

Because of the large number of hours the patrolman spends

in his patrol car, comfort is a factor in his ability to

perform his mission. An officer's efficiency is materially

affected by seating, arrangement of instruments, equipment and

controls, visibility, temperature and humidity. Ease of

entrance and egress and seat belt design can also affect the

effectiveness of the officer's performance.

The National Safety Council [5] reports that for ages 20-59

years, police officers driving patrol cars have significantly

more accidents than the general male population of the same age

group. Occupant safety, therefore, is very important. Safety

of all occupants of the patrol car should be a concern.

Although seat belts are an effective safety device, many police

officers claim they are a handicap in the performance of their

duties, since the officers are in and out of their vehicles

numerous times during a shift. Seat belts also may catch on

equipment carried on the officer's person, particularly his

side arm, and have been reported to have caused personal

injury.

Automobile seats are designed for average use, not for

continued 24-hour a day service. The automobile manufacturers

offer an optional "heavy-duty" seat for police use, which

incorporates thicker padding and a reinforced frame and spring.

The upholstery material should be porous to permit maximum

8.
ventilation. Soft seats will break down with continued use,

requiring the patrolman to assume a less comfortable posture

and cause backaches.

The installation of barriers between the front and back

seats to protect officers from prisoners in the back seat often

restricts movement of the front seat to the position most

comfortable for the driver. Some barriers reduce rear seating

space and may also adversely affect the use of some occupant

safety devices (i.e., head rest and shoulder harness) as well

as presenting a hazard to rear seat passengers in an emergency

s top

The arrangement of vehicle operating instruments and

controls for lights, side view mirrors, windshield wipers, and

horn, as well as the police-added equipment controls for radio,

siren, and warning lights, are other factors which affect a patrolman's performance. The illumination and space provided

for writing and reading reports must be adequate. The

arrangement and availability of storage space for equipment

that must be immediately available is also of concern.

The protection afforded the patrolman by the vehicle body

is an important characteristic. While protection from the

weather is the main function, occasionally the body provides

protection against thrown objects and, to a limited extent,

from gunfire. Along with the driving characteristics, the

various aspects of the vehicle body are some of the most

important characteristics of the patrol car that affect mission

performance

4.6 Vehicle Size

Comfort, safety, and roadability may be major reasons for

the more general use of standard size cars for patrol.

Intermediate-size cars, however, are found in significant

numbers in county and large city departments where cost and

urban congestion may affect the size decision. Aside from the

subjective quality of roadability for highway use, the

difference between the standard and intermediate-size alone

does not appear critical to mission performance.

Smaller vehicles, such as compacts and subcompacts, may

offer some advantages, such as economy and maneuverability in

congested areas. However, the compact size vehicle may also

9.
have negative effects on patrol performance. For instance, it

may be too small for the officer's comfort and convenience, for

passenger and prisoner transportation, or for carrying

necessary equipment. Some compacts may also have reduced

stability, durability, acceleration, speed, and load carrying

capabilities. Even if these potentially negative aspects are

proven to be unfounded, the ability of compact or subcompact

cars to withstand severe police usage for the usual two-tothree year life cycle remains to be demonstrated.

4.7 Engine Performance

Engine horsepower is generally equated with pursuit

capability. A significant amount of power, however, is also

required to operate electrical equipment, such as radios,

lights, sirens, and public address systems installed on patrol

cars. Except for speed, and perhaps to some extent

acceleration, there are no established or widely accepted

criteria for measuring or specifying a desired level of patrol

car engine performance.*

5. VEHICLE SUBSYSTEM PROBLEMS THAT AFFECT

POLICE MISSION PERFORMANCE

In evaluating the performance characteristics of motor

vehicles, a number of components or subsystems can be defined

that individually, or in combination, contribute to each

characteri s ti c

The major relevant subsystems include the engine and power

train, the braking system, the suspension system, the

electrical system, the steering system, the body including its

interior, and the cooling system. These subsystems are usually

individually considered when purchasing patrol vehicles which

have the desired characteristics.

5.1 Brake System

According to the Bunten/Klaus survey [4], 31 percent of the

responding police departments rated brake performance poor over

70 mph (115 km/h), and only 21 of the 50 largest cities rated

brake performance excellent under 30 mph (50 km/h). The brake

system was selected as the second highest cause of

service/repair by all departments, with the larger city

*Mr. G. Ray Wynne, Chief of the Los Angeles Police Department's

Motor Transport Division, suggests that the weight-to-power

ratio should not be more than 16 founds per net horsepower

(9.75 kg/net kW) for pursuit vehicles, and 20-to-l (12.2 kg-to-1

kW) for administrative vehicles.

10.
categories showing the highest rate of repair concern. The

survey also reported that the brake system exceeded all other

patrol car features as needing performance standardization.

Sixteen percent of the survey respondents rated brakes as the

most dangerous feature of the patrol car.

The most often cited cause of inadequate braking

performance was fade, a decrease in friction between the

braking surfaces. Brake fade usually occurs when the brakes

are overheated by either a number of closely spaced

applications or by an extended high speed application. These

occur most often in highway patrol operations or in stop-and-go

urban situations. Fade is also caused when the braking

surfaces become wet.

Two approaches have been taken to reduce the brake fade

problem: the use of disc brakes and the development of more

fade resistant brake lining materials. Disc brakes have long

been recognized as superior to drum brakes due to their ability

to absorb and dissipate heat by having relatively more surface

exposed. Since 1968 disc brakes have become increasingly

prevalent on U.S. production cars and were standard on the

front wheels of 1974 vehicles offered for patrol car use.

Disc brakes, although offering desirable qualities in

reducing fade and dissipating heat, have an inherently

inadequate parking brake action. This drawback is claimed by

the manufacturer to be the most significant reason why disc

brakes are not incorporated on all four wheels. However, since

two-thirds of the braking effort is accomplished by the front

brakes, the performance gains of disc brakes on the rear would

be small and the cost higher. In cases where disc brakes are

offered on all four wheels, small auxiliary drum brakes are

incorporated to provide the parking brake action.

Brake lining materials of three general types are used:

organic, metallic, and semi -metal 1 i c . Organic linings at low

brake temperatures have good fade resistance and offer long

life. At high brake temperatures, organic linings fade, tend

to grab, and have a short life. Metallic linings at low brake

temperatures provide poor braking action, but at high

temperatures, they offer better braking action and fade

resistance. Metallic linings tend to be noisy, however.

11.
Semi -metal 1 i c linings, composed of metal particles bonded

with resin, are designed to combine the best properties of the

metallic and organic type linings. High temperature

performance is good, and the other performance properties are

generally rated between those of organic and metallic linings.

At least one major patrol car manufacturer is providing semimetallic linings as standard equipment on police vehicles.

All brake systems must meet FMVSS 105, "Hydraulic Brake

Systems." However, it would appear from the low reliability

rating brakes received in the Bunten/Klaus survey that FMVSS

105 may not be adequate for patrol cars. A revision of FMVSS

105 is scheduled to become effective September 1, 1975. This

new standard may correct some of the problems of patrol car

brakes

5.2 Suspension System

Of all the components of an automobile, the modifications

made in the suspension system may be the most extensive in

converting a standard passenger car to a vehicle suitable for

patrol car use. Most American passenger cars are designed to

provide a "soft" ride. When an automobile is designed for

maximum control during maneuvers at any speed or road

condition, a stiffer suspension is generally used, and the soft

ride disappears.

In recognition of the importance of the suspension system

to stability and control in a patrol car, manufacturers offer

"heavy duty suspensions", "special handling packages", or

"police suspensions". These suspensions are ordered on the

majority of patrol cars and particularly on those patrol cars

to be used in pursuit operations. Generally, the suspension

modifications will include higher rate (stiffer) springs,

larger, stiffer shock absorbers, stabilizer bars, and often

changes in various bushings, frame reinforcement, and

installation of various other heavy duty components. The

result is a vehicle that has a stiffer ride but can corner more

safely at higher speeds and can be better controlled in adverse

road conditions. A side benefit is possibly a more durable

vehicle.

Design or modification of a suspension system for a vehicle

to obtain the desired handling characteristics is a complicated

engineering problem. The technique for balancing the effects

12.
of the interactions of components of the suspension system is

called "tuning". Some examples of component interactions will

help illustrate the complexity of suspension system design.

Understeer is a handling characteristic of a vehicle that

tends to increase the turning radius as the vehicle progresses

through a turn, requiring the driver to apply increasing force

on the steering wheel in the direction of the turn. Oversteer

is the the opposite of understeer: the vehicle seems to turn

too easily or too fast. Neutral steer is a handling

characteristic of a vehicle that tends to follow the desired

course during a turn with a minimum of adjustment of the

steering wheel by the driver.

Ideally, cars should have a neutral steer characteristic.

However, understeer is considered easier and safer to control,

so, generally, U.S. cars are designed to understeer.

Installation of stiffer springs and a rear sway bar to improve

stability tends to reduce understeer; on the other hand, a front sway bar tends to increase understeer. From this

example, it can be seen that a modification to improve the

handling and stability of a vehicle may have the opposite

effect, if not properly engineered.

5.3 Engine

The broadest range of choices for a patrol car exists for

engine options. These range from four cylinders with

approximately 140 cubic inch displacement (CID) (2.3 liters) to

eight cylinders with 460 CID (7.5 liters). Carburetors may

have one, two, or four barrels.

Standard-size cars designed for pursuit capability usually

have large engines, because it is assumed horsepower determines

acceleration and speed. For urban patrol and the often mixed

urban and highway patrol environment of county operation, the

eight cylinder engine is still preferred. The Bunten/Klaus

survey estimates an average of 91 percent of all patrol cars

specified by all departments in 1972 were equipped with eight

cylinder engines. In county departments, which account for

almost half of the total police cars purchased in 1972, 85

percent specified eight cylinder engines.

Vihen selecting an engine size, police departments generally

consider top speed, acceleration capability, and power required

13.
to operate equipment to be the primary considerations. Initial

cost is likely to be another factor. It would appear that

maintenance and operating cost should also influence engine

size decisions, but, until recently, were often secondary to

requirements for mission performance. Recent trends in engines

generally have been toward continuously increasing horsepower

and engine displacement.

Since 1968, several changes affecting engine size and

performance have taken place. Vehicles have significantly

increased in size and weight. There has been an increase in

the installation of safety devices and accessories,

particularly air conditioning, power steering, and power

brakes. The addition of emission control equipment has

resulted in higher engine temperatures, a reduction in gasoline

mileage, and some reduction in power output. A major portion

of this reduction was due to a change in rating procedures, but

was not a loss of real horsepower.

Prior to the 1972 model year, engine horsepower was rated by

the SAE (Society of Automotive Engineers) "A" curve. Since

1972, horsepower has been rated according to the SAE "C" curve.

This has had the effect of reducing the ratings by about 20%,

although actual engine performance has not been affected.

These trends in engines have resulted in several problems

in patrol cars:

1. Police officers claim the present generation of patrol

cars are less satisfactory for pursuit purposes because of

poorer acceleration and, to some extent, lower top speed.

2. The high percentage of idling and low speed operating

time of patrol cars, always a detrimental factor, has had an increasingly adverse affect on acceleration and high speed

operation.

3. Engines are operating at increasingly higher

temperatures, causing various components to require

maintenance, repair, or replacement at much closer intervals

than in the past. One cause of higher engine temperatures is

the increased use of emission control systems. Table 1, an

excerpt from a report of one large city police department,

aptly illustrates this point. Comparing the 1968 and 1972

models, maintenance cost per vehicle doubled, and engine

14.
Table 1 Before-After Comparisons of Emission Control Effects

(1968 and 1972)

Agency 1968 Average 1972

Indianapolis

Police Department (Fords)*

Engine Size

Mi 1 es per gallon

Valve jobs

Oil change intervals

Engine losses

Marion County ( Ind.

)

Sheriff (Mercury s)

Engine Size

Miles per gallon

Indiana State

Police (Mercurys)

Engine Size

Miles per gallon

289 CID (4.7 1 iters)

16

$1 500/month

5 weeks

0

429 CID (7.0 liters)

14

429 CID (7.0 liters)

14

Other problems with 1972 fleets:

351 CID (5.8 1 iters)

4-5

$3000/month

4 weeks

7

440 CID (7

3-7

2 liters)

440 CID (7.2 liters)

<8

oil breakdown and excessive engine wear

transmission band failures (e.g., in 20% of State's fleet)

exhaust manifold deterioration

disintegration of belts and wires

loss of permanent antifreeze

Comparisons based upon 280 vehicles in each year.

1 5
failures, attributed to the effects of heat, increased

drastically from 0 to 7.

4. While not directly affecting individual officer

performance, the necessity for an agency to increase patrol

fleet funding to cover the cost of increased gasoline

consumption and increased maintenance for patrol cars

ultimately might affect decisions on equipment, manpower, and

training of a police department. These decisions will affect

mission performance.

5.4 Cooling System

In police service, vehicles are subjected to the type of

use that imposes severe stress on many components of the

vehicle. One of these components, especially critical to

overall vehicle operation, is the cooling system. Low speed

vehicle operation, operation of the engine while standing, and

use of large amounts of electrical power for radios, air

conditioning, etc., are common to urban operation and can cause

engine overheating.

High-speed operation at high ambient temperatures, such as experienced in the South and Southwest, is another condition

which strains the cooling capacity of the standard vehicle.

The California Highway Patrol has reported that radiators boil

over in high speed chases in hot desert areas and has

instructed drivers to shut off air conditioners to reduce the

cooling load in such circumstances.

One of the most common causes of mechanical failure is loss

of lubrication between moving parts. If the cooling system

allows the engine temperature to exceed design limits, oil and

grease viscosities may be reduced excessively or other

lubricant properties damaged, resulting in excessive wear and

eventual failure.

Another possible result of inadequate engine cooling is

degradation of the anti-freeze. Generally, anti-freeze

formulations include anti-rust and acid inhibitors to protect

the engine cooling system from corrosion. Heat accelerates

these chemical reactions and the consumption of these

inhibitors, thus reducing life expectancy of the anti-freeze.

The New York Police Department, for example, changes antifreeze about once a month, rather than seasonally.

16.
Automobile manufacturers have provided modifications and

supplements to standard vehicle cooling systems to meet the

requirements imposed by patrol car service. For engine

cooling, these changes may include a heavy-duty radiator, a fan

with additional blades to increase its capacity, additional

exhaust ventilation openings in the engine compartment, a specially designed fan shroud, and a small radiator to cool the

engine oil. An additional transmission oil cooler may also be

provided. The engine coolant may be a 50/50 mixture of

permanent- type anti-freeze and water for year-round use. A

switch may be provided to automatically shut off the air

conditioner compressor under high stress conditions.

Each manufacturer has adopted some combination of these

cooling system modifications to provide a vehicle for patrol

car service.

The main function of the cooling system is to dissipate the

excess or waste heat produced by the engine. Generalizing from

the "Handbook for Mechanical Engineers," [6] approximately onethird of the energy in the fuel burned is used to operate the

vehicle and equipment, one-third is released through the

exhaust, and one-third is dissipated through the cooling

system. The present design practice of locating the radiator

in front of the engine would appear to compound engine

compartment heat problems since the heat dissipated from the

radiator is blown directly back into the engine compartment.

This concentration of heat in the engine compartment must be

assumed to be a major contributor to the degradation of the

performance and durability of most of the components located

there

5.5 Body and Interior

Installation and location of police- related equipment in

patrol cars presents a problem. Each change in body styling

may mean some modifications in installation procedures. These

may include modifying the rack which holds the radio

transmitter/receiver in the trunk, modifying the attachment and

location of the radio control head in the driver's compartment,

and modifying and relocating siren and warning light controls,

or spotlight attachment.

Along with learning how to handle a new patrol car, the

patrolman has to re-learn the location of these controls. Some

departments have estimated this familiarization process takes 2 to 7 days before the operation of the patrol car again becomes

"second nature" [4].

17.
5.6 Tires

Tires are the interface of the brake, suspension, and

steering systems, and the road. They provide the friction on the road surface that stops and starts the vehicle; they absorb

a portion of the initial impact with a road defect; they

provide traction necessary for sure steering; and they

contribute to the comfort characteristics of the body and

affect the performance obtained from the engine and its

emission devices. Keeping safe, effective tires on patrol cars

is a major maintenance cost for police fleets.

The best type of tire for use by a particular department is

not at all clear. The bias ply tire was standard for many

years and is still specified by some departments, f'any

departments have switched to bias belted tires on the basis

that better vehicle performance and greater tire mileage offset

the increase in cost. Currently, a number of departments are

experimenting with radial tires, expecting to achieve lower

operating costs per mile. Although no extensive data are yet

available, several agencies, primarily state police, are

reporting such reductions. On the other hand, some departments

have found radial tires more prone to sidewall damage. One

Department has reduced the damage to acceptable levels by

driver education and by charging drivers for the cost of tires

judged to have been damaged through careless driving.

Tire manufacturers claim that their capacity for producing

radial tires is limited at present. They also predict that as their capacity is increased, radial tires will become the

predominant tire because they contribute to improved handling

and provide significantly increased gas and tire mileage. It

will be some time before the data and technical expertise on radial tires approach our present knowledge of bias

construction. U.S. radial tire production was initiated less

than 10 years ago, with high-speed radial tires for pursuit

application first offered about 1970.

dost tires on the market, of all grades and constructions,

are not suitable for high speed police use. Tests conducted by

the U.S. Department of Transportation indicate that such tires

will fail at average speeds of about 100 mph (160 km/h) [12].

A recent investigation of steel belted radial tires in police

use [12] revealed that two deaths and several injuries occurred

when such tires failed at high speeds. It is important that

patrol cars, which are likely to be used in sustained high

speed driving, be equipped with tires which are certified by

the manufacturer for use at speeds of 125 mph (200 km/h). Such

tires are available for police use.

Maintaining recommended tire pressure is critical to

vehicle performance. Although some effects of over or under

18.
inflation may appear advantageous, maintaining the

manufacturer's recommended inflation appears most desirable.

Some of the more important effects of varying from the

recommended tire pressure include:

1. Uneven tire wear, either in the center of the tread or

on its edges.

2. A softer ride at low pressure and a stiffer ride at

high pressure.

3. Increasing tire pressure tends to change the vehicle's

steering characteristic toward oversteer, while under inflation

increases understeer. It is the oversteer or understeer

characteristic that is most important to the driver in

controlling a vehicle in a turn.

4. Increasing tire pressure results in a tire running

cooler because it flexes less. Heat is the greatest factor in

tire failure.

5. Increasing tire pressure will reduce the amount of

impact the tire absorbs. The result may work the suspension

system harder and cause it to wear faster. Decreasing the tire

pressure has the reverse effect, resulting in the tire

absorbing a higher proportion of impact load than intended.

This may cause cord breakage or cracking of the casing.

6. Varying tire pressure from the recommended level will

also tend to vary the "roll couple" control designed into the

vehicle. "Roll couple" may be loosely defined as the rocking

motion of the front and rear of a vehicle about its center of

gravity combined with side to side roll. One of the main

functions of the suspension system is to control these "roll"

movements, so the driver can maintain control of his vehicle.

These, and other effects related to tire pressures, are used in

the "tuning" of suspension systems during design, development,

and certification of a vehicle. A vehicle user who departs

from the recommended tire size, type, and pressure may change

the handling characteristics of the vehicle and run some risk

of degrading the handling performance.

Tire design affects suspension system performance in a number of ways. Generally, the suspension deflection is 10

times that of the tire deflection. That is, for a 1-inch (2.5

19.
deflection, only a 150-pound (68.18 kg) load is required on the

suspension system compared to a 1500-pound (681.8 kg) load on a tire. If this deflection ratio is changed, as can be done in a number of ways, the change will be reflected in a change in the

reaction of the suspension system and in the handling

characteristics of the vehicle. Generally speaking, the lower

the deflection ratio the softer the ride and, consequently, the

poorer the handling performance of the vehicle.

All major tire manufacturers develop and offer tires

certified for speeds up to 125 mph (200 km/h) to meet the high

speed pursuit requirements of patrol cars. In contrast,

passenger car tires generally are certified for maximum speeds

of no more than 85 mph (140 km/h) under the R1VSS. However,

tire certification has other ramifications.

Before a motor vehicle can be sold in the United States, it

must meet the standards of both the National Highway Traffic

Safety Administration (NHTSA) and the Environmental Protection

Agency (EPA). Individually components and subsystems of the

vehicle (i.e., lights, brakes, tires, bumpers, restraints,

etc.) are covered by NHTSA's Federal Motor Vehicle Standards

(FMVSS), and must be certified by the automobile manufacturer.

Under EPA regulations, the total vehicle system must be tested

and certified as satisfying emission standards. Once a particular combination (model) is certified, the manufacturer

is limited in the number of changes he can make, or options he

can sell with that vehicle, without re testing and

recert i f i cation

.

As a consequence of the certification procedures,

continuing use of the designated tire types is important to

retaining the performance of the patrol car as purchased.

All three types of tire constructi on--bi as , bias-belted,

and radi al --reportedly have been certified by various tire

manufacturers for 125 mph (200 km/h) police service. According

to the Rubber flanuf acturers Association, it is preferable that

all four tires on a car be of the same size and construction.

Under some circumstances, mixing of radials and non-radials is

acceptable, but not preferred. However, radial tires should

never be placed on the front wheels if anything other than

radials are on the rear wheels.

5.6.1 Bias Ply

Bias ply tires have stiffer sidewalls largely because of

the angle of the cords and the number of plies in the body.

They have more rubber in the tread, primarily in the shoulders.

In general a bias ply tire has:
1. Good low speed ride properties.

2. Low road noise.

3. Lighter steering load at low speeds and in parking when

compared with radial construction.

4. Good break away resistance in a high stress maneuver,

i.e., no sudden or unexpected loss of traction.

5. Good resistance to sidewall damage.

6. Fair tread life.

Since the bias ply tire is so widely used in this country,

supply is no problem.

5.6.2 Radial Ply

Radial ply tires have quite flexible sidewalls and stiff

treads with no shoulder. In general, a radial ply tire when

compared to a bias ply tire has:

1. Lower rolling resistance and improved gasoline mileage.

2. Longer tread life.

3. better cornering ability.

4. Better traction and braking grip.

5. More ability to roll over small grooves or ridges in

the road with less direction change or wander.

6. Better high speed ride.

7. Greater susceptibility to sidewall damage.

The radial tire is just coming into common use on U.S.

automobiles; the 1974 models were the first to be designed

to use them. Radial tires require more process steps in their

construction than do bias or bias belted tires; hence, they

will likely continue to be the highest in purchase cost into

the foreseeable future.

21 .
It should be noted that most radial tires (like those of

other constructions) are not suitable for use at speeds above

about 100 mph (160 km/h). Some, however, are specially

designed for use at speeds of 125 mph (200 km/h); these may be

belted with either steel or synthetic material. Departments

which require such high speed performance should purchase only

tires which are certified by the manufacturer to be capable of

such performance on the basis of sustained high speed track

tests.

5.6.3 Bias Belted

Generally, the performance

are somewhere between those of

A bias belted tire has:

1. Better high speed ride

speed ride than radial tires.

properties of bias belted tires

bias ply and radial ply tires.

than bias tires and better low

2. At low speeds, a heavier steering load than bias ply

tires, but a lighter steering load than radial tires.

3. Less resistance to sidewall damage than bias ply tires,

but more resistance than radial tires.

4. Longer tread life than bias ply tires, but less tread

life than radial tires.

5. Better cornering ability than bias ply tires, but less

than radial ply tires.

5.7 Electrical System

Host motor vehicles equipped for police patrol have a large

number of electrically powered devices installed in them.

These may include: mobile radio transceiver; additional mobile

radio receivers; siren (electronic or electro-mechanical);

emergency lights; public address system; spotlights; and

additional stoplights or colored warning lights.

In addition, there is an increasing tendency to install

more electrical accessories such as: air conditioner, deck lid

release, power windows, power door locks, and power adjustable

seats. Police often find it necessary to operate much of the

electrical equipment while the engine is idling or even turned

off. These extended electrical drains sometimes cause starting

and battery maintenance problems. Furthermore, in high speed

chases air conditioners and electro-mechanical sirens drain off

significant engine power and reduce maximum speed.

22.
Several innovations have been made by manufacturers to

promote longer electrical system life. Higher capacity

alternators, both in normal output and idle speed output, have

been installed. Shields have been placed around the battery to

protect it from heat, as well as from stones thrown up from the

road. ueteri ora ti on of the alternator belt has been a longstanding problem. Dual alternator drive belts were tried, but

have been discontinued by most n.anuf ac turers . The best

solution to belt deterioration ultimately is to make

improvements in belt quality. Research is underway to develop

belts made of Kevlar, a high strength synthetic fiber.

Other electrical system problems may also be attributed to

heat effects. Llectrical conductor failures, such as short

circuits, are often the result of insulation breakdown

accelerated by engine compartment heat. The ignition wiring is

one of the common victims. Efforts are being made to combat

heat by the use of high temperature resistant wire insulation,

but this problem has not been completely solved. Heat

degradation problems appear likely to increase since the trend

is to increase engine operating temperatures.

With tne seemingly continuous addition of new electrically

operated equipment to vehicles, additional electrical capacity

and maintenance of system reliability has become an ever

increasing problem. Many of the solutions offered involve

replacing electro- mechanical devices with solid state

electronic equipment: sirens, emergency lights, ignition, and

voltage regulators. Electronic ignition, which is claimed to

eliminate much of the maintenance required to keep an engine

operating efficiently, is standard presently on one

manufacturer's vehicles and available on some others.

5 . 8 Steeri ng

Steering characteristics are important to mission

performance at any speed. A report on police vehicle accidents

in a large city shows the majority occur while cruising at low

speeds [5]. The ease with which a patrol car steers

contributes significantly to the driver's comfort and

efficiency. Precision of steering is important in pursuit

operations, particularly in evasive maneuvers, regardless of

the speea.

23.
Domestic motor vehicles used for patrol cars are equipped

v/ith a type of steering gear known as the recirculating ball

and nut. These have been combined with power assist and

developed to a degree that police consider steering performance

at normal vehicle speeds satisfactory [4]. If the components

in the steering system are not kept in adjustment and in good

repair, however, the likelihood of steering malfunctions are

increased. Faulty adjustment and poor maintenance can not only

adversely reflect steering performance, but can increase

operating costs unnecessarily. Hot only the steering gear

itself, but all the components which work together as the

steering system are critical. These include not only the ball

joints, tie- rods, bushings, pitman arm, etc., but also such

things as front wheel alignment and tire balance.

5.9 Emission Control System

As seen in table 1, emission control devices appear to be

an important factor in patrol car performance. Since the

introduction of emission controls:

1. Horsepower produced for a given engine displacement

volume has decreased.

2 . Vehicle weight has increased.

3. Gasoline mileage has decreased.

4. Higher engine compartment heat levels have increased

heat failures in insulation, gaskets, valves, etc.

Current emission control devices can be considered only

interim measures. The Federal emission standards effective on 1975 model automobiles are being met on some makes of cars by the

use of a catalytic converter, a special device which is

installed in the exhaust system and which converts the harmful

emissions into water and carbon dioxide through a chemical

process. Those converters in current use, however, will be

seriously damaged by leaded gasoline.

24.
6. PATROL CAR ACQUISITION

Each time a law enforcement agency acquires new vehicles, a set of specifications is prepared and offered to vendors for

bid. An examination of the specifications obtained from police

organizations across the country shows a wide variation in

approach, from brief one page lists to very detailed, multipage lists. A general pattern is apparent, however. Usually,

a very brief statement is furnished to the bidder regarding use

of the vehicles. This may be a few words such as "automobiles

for police activity", "sheriff patrol cars", "four-door sedans

with heavy duty police equipment", or "for routine police

patrol, traffic control, and other work required in the

operation of a police department".

In a few cases, service requirements have been described at

some length. For instance, the specification of the City of

Milwaukee, Wisconsin, states that "the vehi cl e . . . wi 1 1 be

exposed to the most severe service to which a vehicle can be

subjected," and then describes in qualitative terms the extent

of use and wear to be expected on various parts of the vehicle.

The necessity of providing heavy-duty parts and options is

stressed. Another example of more definitive service

requirements is that supplied for the California Highway

Patrol, Class "A" Special Service Vehicle.

"It is the intent of these specifications to describe an

automobile to be used in high speed highway traffic and law

enforcement work. The vehicle will at times be operated at

speeds considerably in excess of 100 miles per hour (160 km/h)

for both short and long durations. It will be driven on all

types of roads and road surfaces and at altitudes ranging from

approximately 200 feet (60 meters) below sea level to 10,000

feet (3050 meters) above sea level. Temperatures to which the

vehicle will be exposed will range from approximately minus

20°F (-29°C) to plus 120°F (+49°C).

"It is intended that the manufacturer in the selection of

components will use materials and design practices that are the

best available in the industry for the type of operating

conditions to which the vehicle will be subjected. Engine,

transmission, drive line, differential, brake, suspension,

wheel, tire, and other component parts of the vehicle shall be

selected to give maximum performance, service life, and safety

and not merely meet the minimum requirements of this

specification.

25.
"The term 'heavy duty' as used in these specifications shall

mean that the item to which the term is applied shall exceed

the usual quantity, quality, or capacity supplied with standard

production vehicles; and it shall be able to withstand unusual

strain, exposure, temperature, wear and use."

6.1 Design Specifications

The vehicle requirements are commonly soelled out in what

might be called "design" terms. This means the specifications

will list requirements such as the number of cylinders, cubic

inch displacement, and horsepower of the engine; the type of

alternator; the size of cooling fan; type of brakes; number of

doors, and the size of the wheelbase. In addition, the

accessories may be listed: air conditioning, spotlights,

remote-controlled outside mirrors, inside hood and trunk

releases, hand throttle, and others desired.

The "design" approach, describing a vehicle for patrol car

use by specifying the individual components, appears to have

developed from the practice of the automobile manufacturers

offering a large number of options and accessories for their

police patrol vehicles. Through experience and in consultation

with the manufacturers, patrol car users have apparently

reached reasonably effective vehicle "designs" for their

specific requirements.

There are serious disadvantages to using the "desian"

approach for specifying vehicles for patrol use. The majority

of persons responsible for developing specifications are police

officers, who have developed their knowledge of vehicles

largely through using them. Only a handful of the larger

departments have automotive engineers on their staffs. The use

of design specifications requires a thorouah understanding of

automotive design to provide the most satisfactory vehicle for

a given service.

Almost every model year, manufacturers offer new options

and new accessories. Although organizations should take

advantage of these new items whenever patrol performance would

be improved, few departments have the capability of evaluating

optional equipment to determine what benefits might be

provi ded .

26.
The lack of in-house expertise often results in

specifications being developed that cannot be met. Some

problem specifications develop v/hen there is an unawareness of

technological advances, certification procedures, or physical

design limitations.

Perhaps the most important disadvantage is that the

purchaser has no guarantee that the vehicle he "designed" and

purchased will provide the performance or the service desired,

and if it does not, he can do little to require the

manufacturer to correct the problem.

6.2 Performance Specification

Another approach to writing specifications is to specify a level of performance. Specified levels of performance and

tests for handling or roadability, braking, acceleration, and

top speed illustrate this type of specification. The city of

Los Angeles has been a leader in developing specifications

based on performance. The city and county of Los Angeles use

the same specifications, which include the following

roadability and brake test procedures:

"ROADABILITY TEST:

Vehicles will be tested for cornering, steering, and other road

handling characteristics at the Pomona Fair Grounds Sports Car

Track or other suitable place designated by the Sheriff's

Department. Vehicles will be evaluated by the driver and

passengers conducting the test and the opinions will be

considered in rating the vehicles for over-all suitability.

The actual test shall be conducted by two or more separate Los

Angeles County drivers who will take four practice laps of the

designated course to familarize themselves with the vehicle.

Following this, four additional laps will then be completed and

the roadability of the vehicle noted by the driver. The

drivers will evaluate the vehicle for ease of handling in

corners and turns, for ease of control at high speed and ease

of steering at slow speeds. Vehicles must accelerate from 0 to

60 mph (95 km/h) in not more than 9 seconds, and have a top

speed of not less than 115 mph (185 km/h).

BRAKE TEST:

The brake test shall consist of two parts as follows:

27.
1. Four stops of impending skid type from a speed of 90 miles

per hour (145 km/h) at two minute intervals followed by a panic stop from 60 miles per hour (95 km/h) will be made,

at which the ability of the vehicle to stop in a straight

line will be evaluated.

2. Five minutes after the panic stop has been completed, four

more stops at 90 miles per hour (145 km/h) of the impending

skid type at two minute intervals followed by a 60 mile per

hour (95 km/h) panic stop will again be performed, and the

ability of the vehicle to stop in a straight line will be

eva 1 uated

3. Cars equipped with a self-adjusting brake feature will be

subjected to the following test immediately following

conclusion of the above brake test:

There will be four (4) successive brake applications made

on the vehicle with the car being driven in reverse. If it

is found that the self-adjusting brake feature adjusts the

brakes to the extent that the wheels drag when the rear

drums cool down the vehicle will not be acceptable.

Vehicle deceleration rates will be recorded by the use of a decel erometer and pressometer to determine the brake fade

characteristics of the vehicles submitted for testing.

Vehicles failing to pass this test will not be considered

qualified for this bid."

More and more jurisdictions every year refer to the results

of the Los Angeles tests to guide their procurement. It should

be pointed out, however, that these tests have been developed

by the LAPD to meet their particular operational requirements

and driving conditions, and cover only i n termed i ate- s i ze

vehicles.

6.3 Acquisition Procedures

A general pattern is apparent in patrol car acquisition

procedures. Specifications are generally prepared on a model

year basis, shortly after information is released on the new

models. The development of written specifications varies

widely, but in most cases police agencies are given major

responsibility. Vehicles are normally purchased on low bid,

but in some cases specifications appear to be written to favor

a desired make or model. This latter approach has been used

when a department has had good performance and service from a particular vehicle, good service from the dealer on maintenance

and repairs, and so on. Bids are usually opened in November or

December, and delivery generally starts in January or February.

Quite often provisions are made to purchase replacements for

wrecked vehicles during the model year.

28.
Used vehicles are often traded in on the new vehicles.

Some agencies conduct their own sales of used vehicles,

claiming a better return. The North Carolina Hiqhway Patrol

over the years has extensively refurbished its used patrol cars

and sold them to smaller jurisdictions for police use, thereby

minimizing its net acquisition costs. A few agencies use their

cars until there is essentially no residual value; New York

City is one agency that follows this practice.

6.4 Life Cycle Costs

Although the initial cost and the maintenance cost of a vehicle may not be associated with patrol performance, high

costs for vehicles coupled with budget restrictions might limit

an agency's ability to meet its transportation requirements.

This, in turn, would presumably reduce the agency's

effectiveness.

Costs of new, full-size, four-door sedans equiDned for

police use vary from about $3300 to $4 or>0, denending upon the

options ordered. Trade-in values for two-year old cars in 1972

ranged from $900 to $1300. Net costs appear to range from

$2000 to $3100 per new car.*

A fuller discussion of patrol car economics can be found in

the section of this report on vehicle fleet management.

The LAPD procedure in acquirinq new vehicles varies from

the norm and is worth specific mention.

1. Specifications for vehicles are sent to the

manufacturers shortly after the new model information becomes

available each year.

2. Automobile manufacturers submit models eouinped

according to specifications of the LAPD for test in accordance

with the specified procedures.

3. Vehicles which pass the tests are imoounded until the

bidding procedure has been completed. Manufacturers whose

vehicles do not pass the tests are not eligible to bid.

4. Vehicles are purchased on low bid, after which the

impounded vehicles of unsuccessful bidders are released. The

vehicle of the successful bidder is retained for comparison

with the first fifty vehicles delivered by the contractor.

*Tnis survey was conducted in 1973-197 4. Costs do not reflect

current n.arket prices or trade- in values.

29.
This procedure, developed over a period of time in

conjunction with the automotive manufacturers, has resulted in

patrol cars which are considered by many to be among the best

in the country. The procedure has also provided the automotive

manufacturers with an independent evaluation of their police

car models.

7. VEHICLE PERFORMANCE TESTING

In order to provide a vehicle of optimum characteristics

for a particular police application, an evaluation procedure is

desirable. Criteria related to the user requirements, against

which the evaluation would be conducted, are also desirable.

There are no performance oriented tests available that have

been developed for the total patrol car, highway or urban.

There are some tests required by law that apply to certain

aspects of performance. For example, certain performance tests

are already required of all vehicles by the FMVSS. The FMVSS

cover brakes in Standards 105 and 106, tires in 109 and 110,

and bumper impacts in Standard 215, to mention a few. However,

while the test procedures adequately cover standard passenger

cars, no procedures include the conditions under which police

vehicles are expected to perform. For instance, many patrol

cars are specified for operation to 125 mph (200 km/h) , up to

45 mph (70 km/h) beyond the test range of the FMVSS. Handling

and maneuverability are critical to police usage, but high

stress maneuvers, such as lane changing, turns, and cornering

at high speeds, are not covered in the FMVSS. Controlled

stopping from high speeds is another patrol car performance

attribute not covered in the FMVSS.

Recently, the Highway Safety Research Institute (HSRI), Ann

Arbor, Michigan, completed a project for the U.S. Department of

Transportation (DOT ) to provide data on the effect of high

stress maneuvers on vehicle stability [7]. The HSRI study

developed some test procedures that could be highly relevant to

police patrol car requirements. HSRI developed reproducible

techniques for measuring the response of vehicles moving at 50

mph (80 km/h) to such things as lane changing, turning, turning

with braking, and turning with braking on a rough road surface.

While this work was performed on a variety of vehicles for

research purposes, the techniques appear quite applicable for

evaluating the performance of police vehicles.

30.
With au equate test procedures, it w o u 1 d be possible to

conduct annual performance tests of all the vehicles offered as patrol cars by the various manufacturers. These tests should

include acceleration through various speed ranges, braking

under varying conditions, cornering and lane changing at

various speeds, and off-road properties (curbs, median strips,

etc.)- Properly designee and expeditiously performed and

reported, the results coulu serve as a factual input to any law

enforcement organization purchasing new patrol cars. There are

a number of independent test centers which appear to be capable

of conducting patrol car performance tests, once the test

procedures have been developed.

£. VEHICLES IN CURRENT USE AS PATROL CARS

The Bunten/ Klaus survey provides a description of the

typical patrol car specified for purchase in 1972. A total of

530 police departments provided data concerning their patrol

car experiences. This survey included data from the police

departments of 47 of the 5C states, 46 of the 50 largest

cities, and representative samples of counties, smaller cities,

and townships. It should be emphasized that the data in the

survey are based on the specification last usea by each

reporting department to purchase patrol cars and hence does not

present a truly accurate picture of the total fleet in current

use

Oaseu upon survey data, the total number of police patrol

cars in use was estimated to be 160,000. However, this is

considered to be low since an estimated 10,000 to 12,000 snail

and part-time police departments were not included in the

survey. By including these small departments, the total could

easily be 1 0 ,000 to 20 ,000 higher. If the survey data are- applied to the estimated national patrol car fleet, it can be

estimated that of these 160,000 vehicles, 60 percent were

standard-size 4-door sedans, or 73 percent when 2-door sedans

are included, 21 percent were intermediate-size 4-door sedans,

or 23 percent when 2-door cars are included. The remainder

were station wagons and compact cars. A more detailed

breakdown is shown in table 2.

These vehicles were not all equipped with special policeoptions. About 80 percent, or about 127,500 cars, were found

to have heavy-duty suspensions. The other 32,000 vehicles were

apparently standard vehicles, i.e., without police heavy-duty

suspensions, or the other heavy-duty options associated with

the patrol car. Details arc given in table 3. The division by

vehicle type is substantiated by the estimate of 65-70,000 new

cars equipped with police options sold by the manufacturers in

the 197 3 model year.

31 .
4-J O

A3Q.Eoo

CTi O

CM

CICO

cr cn o CO

ro ro

•» CVl

toso

•r—

+-> TOOo

0Jc

to

CM

cn co c ci S P- o CO «* CM to co CC CM ro cm

+-> o- cr CM CM

10 LO CO LO <- OJ +J 15 n 00 CM LoOco

too

O- c

-o

CD to

OJN

r~

to o o LO CM CM CO o CO ID CO CO

•ai CO to tC to CO CO

«3- CM

CO CM CM

ro

CM

a; S- to E o LO 1 1 CM

C

fO S- o ro CM

O

CC te TJ1 CM

4-> c CM CM —I

i— CM

ro

i~ t- o r— cr cr CO c cr. CM re C o LO CM ro CM cr ro «* to o (O o vo CM CM a- to

OJ "O T3

OJ l LO Is* to CO CC CM CTi o to CM ro o

TO S- 1

Pat

Size S-o c cn LO co CM c CO "el- re o ro r— CTl ro ro c "O ro CC c to o n r- u. CM CM tc

•o

CJ

»-> r—

re re E •*-> i- o

-M I

to LU o to to ro c LO o

to cr> cn CM c LO r— c

CO CM CO CT>O ro

cn c to c c LO to cr. CM LO o to

t- -o to 0J to to

<D Su S- OJ -M +J QJ OJ - r- re c u o +J E CJ •r— 4- •I- •r- E o *t- O +-> -M OJ «4- to S- Q. o cn o +J UJ re >i D-|— c. cn

«d-i + es

OJ i o o cn +-> o >> x: p*—•

LO S- c

OJ •-> to re OJ +j c c >> >> _j re u

re =3 +j 4-> +->

M J- +j O o f— •r- o o OJ to o h- o O O LO 1—

re

to

OJcn

re

+->c

a;a

sQJC

+-> c

QJE

-M

S-rea.

QJ T3

cncc

re

=o XI

T3

OJ • >

•r- I S- <

OJ CM O

QJ • JD

>, re

aj 4-> >

s- « ^ i—

to re

4-> to O

re i— *o ^ QJ \ 4-> c re QJ E

+-> ••- £Z 4-> 3 V) CO QJ

QJ(J

S-3o

to
to

+-> c C tc (£5 CO o tn o in cr CT> cr CM cr in c

QJ co CM CO cr. cr oo

re cr cr to c cr ur cr. E cv in

4-1

IO

a;u

r— -C

CD "O > S_

CVJ re o

CT s- c

da ta

C c oo

rta

to OO co

CO

at

00>

CJu

•f

<4- 0)c

1—

U Dl c

o> • r— o

Cl =1 •r- 00 cr

LlI

+-> CL

s- o

c_; on ce o 4-> s- C_ o

»-)

O Q.

re

CL- CJ

CO cr in IC

m c o

CO CO on CJ CM m <xj ir IX, CO m CO

CM CM r— CM

CM CO

cr IC CM

m cr r-- c

cr IC 00 c tn CTi CO in CJ m CM co CO

CO CO

m CO CO CO

CM CM c

•r— >>

QJ to +J c c

re 5 o o

00 CJ 1

00

Sto OJ I/) i- o $- <U QJ o *4- O

•r— <4- O M-

<4- o cn o

cr. i + c om

>> >> >>

-M +-> 4-> •rC_) O o

to

O)

4-> •r— O

4-> to

CUCD +j

f~ c

re a; _i re u

+j i_ o o a* m 1— I <

CM S-QJ to re S- a- rs i— o ±j -O 4-> u

re re

4-> -cs *«- CD Z5 c -t-> C

•i- re reE

re c

-t-> a; QJ re TD = E O O •!- -Q

S- O0 fr C T3

CJ QJ -O Cl S» CU 10 QJ

+-> =5 «4- re to «*-c 3 > U 4-> QJ r— =3

re "O

U

O 1

QJ > a

i- re >

a- cu S jc re c 0% o re QJ jc jr

to 4-> »f—

to c ^> a> o QJ $- -r- 3 -M U

CTi

C

•<- E JC s_ 4- 3 QJ re

</) > o

QJ to j= re "O QJ h- QJ O

0)

C r~ c • 4-> t— C

>> Cl

cr > o QJ re i-3 -o to to CJ c re to o

to re r— >> 3 .a +j i—

re Q-r—

i— -ore ^ CM U \ i cu c cm <j M—

QJ <-—•— •—

-M i—

O

C "O

O QJ 3 C D- CL

CO re = 00

QJO

S-o

CO
The optional equipment specified by the departments studied

in the Bunten/Klaus survey is shown in table 4. Of the

thirteen options listed, six were specified for over 80 percent

of all vehicles: automatic transmission, 8-cylinder engine,

power steering, power brakes, front disc brakes, and heavy duty

suspension. A comparison of these 1972 options with the police

vehicle specifications of 1974 model year vehicles offered by

the four domestic manufacturers, tables 5 and 6, shows that all

of the first six listed options are now standard equipment for

full-size police vehicles. Of the other seven options listed

in the survey, the interior hood latch release has become

standard on full-size cars and on some intermediate-size cars.

Certain features that are options to the general public have

become standard features in a police vehicle for the 1974

model. The features in the so-called "police package" listed

for the 1974 model year include:

Automatic transmi s s i on

Power brakes (front disc)

Special handling package (heavy-duty suspension)

Special radiator cooling package (heavy-duty)

Power steering

Interior hood latch release

Heavy-duty front seats

Calibrated speedometer

Heavy-duty wheels

Police special tires

Higher capacity alternator

Higher capacity battery

In addition to these features, manufacturers nay add other

equipment which is deemed necessary to provide the performance

required of patrol cars. Quite often, for instance, vehicles

equipped with the largest engines will have auxiliary

transmission oil coolers and external engine crankcase oil

cool ers

.

Generally, all of the optional equipment available to any

car buyer is also available for inclusion in a patrol car. The

lower part of table 4 shows air conditioning, tinted glass, an interior hood release, a light in the trunk and an interior

trunk release included on large percentages of patrol cars.

The rationale for including these items is that they improve

the effectiveness of the patrolman. Air conditioning is

provided to reduce fatigue. Tinted glass reduces the effect of

solar heat and improves the efficiency, but reduces night

vision. The interior hood release is intended to prevent theft

and preserve the integrity of the vehicle. The interior trunk

release and the light in the trunk speed access to equipment

stored in the trunk. Some features may have an additional

justification based on improving the resale value of the patrol

car. From table 4 it would appear that state agencies lead in

adding options.

34.
inc

o

•r—

4-> <C

(J

o

a

C- CO

C\J

cr.c

c

T3

<D

in

TJ COm

S-<a o

CLC

o

s-c

on

in

<D

(JO

<

4J

a:<£

Cl.

or

4-> in

ai

cr. c

^_ LO

1/1 i-ai +

u c

LP,

t|_

<3

in

S-a; c-. o «=}-

1 i

j

in

Scuu cr

4-

4-

Lonun^-i^^i— cm r^ r-^ «3- cn cr- cr cccocONicq-nro

CO^^J-COCvil^CTit— n c\i cc co m

racrcococoLn^^<a-cn

ir m lt c s n i— r^^-i— cr-. c\j

3

co

+-> co

i— tr- ee ai O

Cf'Of^fomocMu-jL.ocriCMOc:

C^CTiC^COOTCriLn^^rLOCC

r^incric\jcrccrocrir^i£>c\JcO'* cccor^cor^ic in n

cocoi— id co co (- Or— ioor^

craiCiciCTiccor^coiflitrir: o id ^- co c cvjcr. mso^-

c^cricricocccOLnLn«^-«c-fOi

a

c

ro c <D o C on in •r— I/) rc c in <o CD c in 0)

•r— •i- a; QJ

-t-> E = cr. CD Q£

D- in "i— c a: c

o •f— Jx£ f0

ro c c: c c "O c

S_ LU •!- 00 O O in o =3 3 in

I— s- CJ in •i- •!- in c S- S- in •*-> J- o OJ in +-> (O 1— 1— f0 f0 U <U CJ c: -r- r— C3 CD

•r- T3 +-> i_ CJ-DC s_ c s- CO

4-3 C CO CC a. c o o cr.

(13 T- CQ "r- e +-> E — 5- S_ 3 O CJ +-> s- •r- OJ O >> OJ 0) U(/l +-> <v QJ +-><_> 2 3 in i. E 4-> cr 4-> (J o

3 1 O O O T- -r- c C O 3

<CCQ- CL 31 <C H- 1—_j __I ca o CSJ CO

r— CNJ CO «3- lt) id r-. co cti

CNJ

CJ .a

a

>

c

CD

4-> c

3

ca

aio

i-3o

CO
Table 5

Typical Full-Size 4-Door Sedans Offered for Police Patrol by the Manufacturers 1174 Model Year

MANUFACTURER

MODEL NAME ENGINE SIZE (1) Displacement, CID (2) AUTOMATIC TRANSMISSION

Lowgear Lockout

Auxi 1 i ary Cool er ELECTRIC SYSTEM Alternator, AMP Generator, AMP Battery, AMP Electronic Ignition

BRAKES, Front Disc Power STEERING, Power

Oil Cooler

HEAVY DUTY HANDLING PKG. Springs, Front and Rear Shock Absorbers, F&R Stabilizer Bar, Front

Rear Front Strut Bushings

Upper Suspension Arm Bush Control Arm Bushings

Front Spindles

Reinforced Frame SPECIAL COOLING

High Capacity Fan Fan Shroud

High CaDacity Radiator

Coolant Recovery System

External Crankcase Oil Cooler

HEAVY DUTY WHEELS, 15x6.5

1 5x6.0

TIRES

Bias, 4 Ply Nylon

Bias Belted, 4 Polyester

and 2 Fiberglass Belts

P.adial , 2 Polyester and

4 Rayon Belts OTHER ITEMS

IID Front Seats

HD Floor Mats

HD Flasher Unit Interior Hood Release

Interior Trunk Lid Release

Single Key Locking System

Calibrated Speedometer

Automatic Parking Brake Release

Ameri can Ambassador

Med. Max

.

360-2 401-4 STD(3) STD STD STD

SO

62 62

80 80

STD STD

STD STD OPT OPT

STD STD STD STD

STD STD

STD STD

STD STD

STD STD

STD STD STD STD

STD STD

STD STD

STD STD

SO SO

STD STD

OPT OPT

OPT OPT

STD STD

OPT OPT

STD STD OPT OPT

OPT OPT

STD STD

Chrysl er Fury/Monaco

Med. Max.

Ford Custom 500/Galax.y General M o t. o r s

360-2

STD S0(4)

OPT

65

70STD

STD

STD

STD

STD STD

STD

STD

STD

STD

STD

STD

STD

STD

STD

STD

SO

SO

STD

STD

STD OPT

OPT

STD

440-4

STD

SOOPT

65

70STD

STD

STD STD

STD

STD

STD

STD

STD

STD

STD

STD

STD

STn

STD

STD

SO

SO

STD

STD

STD

OPT OPT

STD

Med. Max. 100-2 460-4 400-2 4 54 STD STD STD STD

STD STD 0PT(5) OPT

STD

70 00

42 42 80 80 80 80 STD STD

STD STD STD STD

STD STD STD STD

STD STD STD STD

STD STD STD STD STD STD STD STD

STD STD STD STD STD STD STD

STD STD

STD STD

STD STD

STD STD STD STD STD STD

STD STD

STD STD STD STD OPT STD

STD STD

STD STD

STD STD OPT STD

STD OPT

OPT OPT OPT OPT

STD STD STD STD OPT OPT STD STD

STD STD STD STD STD STD

SO SO OPT OPT SO SO STD STD STD STD STD STD

NOTES: (1) Data on models with different size engines gives some indication of diversity in equipment

offered

.

(2) Displacement data also shows number of barrels in carburetor( s ) in the figure after the dash, "440-4." Usually 4 barrels indicate the use of 2 carburetors. Metric equivalents of CID are

as follows in liters: 360 (5.9), 401 (6.6), 360 (5.9), 440 (7.2), 400 (6.6), 46C (7.5),

400 (6.6) , and 4 54 ( 7.4 ) .

(3) "STD" means standard equipment on vehicles offered for police use. May or may not be standard

on regular production models.

(4) "SO" means available only on special order; sometimes only if a minimum number are ordered.

(5) "OPT" means available as regular production option.

Source: Specifications released by manufacturers in August 1974.

3 6
Table 6 Typical Intermediate Size 4-0oor Sedans Offered for Police Patrol by the Manufacturers, 1974 Model Year

MANUFACTURER American Chrysl er Ford General Motors

MODEL NAME Matador Satellite/Coronet Ton no Chevelle

cur tuc c t 7 c f 1 ) t 1 j 1 .1 t b i L L \ \ } Med

Man v a a . Marl Mn a v a X . Mori n eo May n a X . Ma v i a x .

J 1 SD 1 aCci ic" L , LIU ; C JUU"t HU 1 -H 7 n a A A n A H H U - 4

7. E 1 9 o b I - c a £ n. d 4 D U TM 4

a on 9 Hull" C AU 1 Unn I 11 1 K Mil J il 1 J j 1 U li CTn / •> \ J I j I J J bCTn1 U CTn bCTn1 U MA / it \ m n nil CTn b 1 u Lowgear Lockout o i U cth bu ' b

c n b U CTn b 1 U CTn b 1 Uc n bU Auxiliary Cool6r co un cJ Vn npT / f \ riUrDTI Tl FPTDTT CVCTFfl Alternator, - - Milr AMD D C K9 D 3 d b / U 90 b 1 Generator, AMP

RDaa *-LtLcry a r* \i , HPir AMP 80 80 70 70 7 7 7 7 Electronic Ignition CTn j 1 u CTn HPT U r 1 CTn b 1 U

Q n i l' C C C r n n t n i' e r CTn j 1 J CTn CTn CT h o 1 U

C T n b 1 U CTn b 1 u CTn b 1 u

P owe r STD CTn CTn CTn CTn b 1 u bCTn1 u C Tli b 1 U

j i L L k i n u , rower OPT OPT fiDT Ur 1 UrHPTI un CTn b 1 LI

:j

I 0 Oil Cooler bCTnI J bCTn1 U ntnVT ucai/y nilTV UU1T UANHI nMHULlitU TUG P" KNu,G STD STD STD CTn bCTn1 u CTn b I u CTn Springs, Front and Rear STD STD CTn J 1 u STD CTn

STD STD STD STD STD Stabilizer Bar, Front STD CTn CTn OCTn1 u CT O Rear STD STD CTn CTn CTn Front Strut Bushings cm CTn j 1 u Upper Suspension Arm Bush. j 1 u CTn Control Arm Bushings CTn CTn Front Spindles

Reinforced Frame STD CTn CTn CTn b 1 u CTn

c pft t ai rnni t ng STD STD STD STD STD STD STU High Capacity Fan STD CTn STD STD STD

Fan Shroud CTn j 1 U

c Tn CTn CTn b 1 U CTn b 1 V Hich Capacity Radiator cxn j 1 u CTn j 1 LI CTn CTn j 1 u CTn b 1 u bCTni j CTn b l u Coolant Recovery System cyn o I Lf CTn CTn bCTn1 u bCTn1 l) cth b I J CTn b l u External Crankcase Oil Cooler

L1CAWV nilTV iinrrt f 1 C w 7 f\ HtAVY UUIY vinttLb, IbX/.l' n d t 15x6.5 bCTni u CTn b 1 U 15x5.0 STD CTn b 1 u

1 4 x F . 0 ST" TTDCC 1 IKt j Bias, 4 Ply Nylon bCTn1 U cth b I J OPT STD 0 PT

o 1

- a- s- t>e i leu A Dn 1 in c far , 1 "uiyester

and 2 Fiberglass Belts OPT OPT SO SO OPT

Non Police STD Radial, 2 Polyester and

4 Rayon Belts OPT OPT Fabric OPT OPT OPT OTHER ITEMS

HD Front Seat STD STD STD STD STD STD SO

HD Floor Mats OPT OPT STD STD OPT OPT SO

HD Flasher Unit Interior Hood Release OPT OPT OPT OPT STD STU STD Interior Trunk Lid Release OPT OPT OPT OPT OPT OPT SO Single Key Locking System OPT OPT OPT OPT SO Calibrated Speedometer STD STD STD STD STD STD STD

:.0TES: (1)

(2)

(3)

(4)

(5)

(6)

Data on models with different size engines gives some indication of diversity in equipment offered.

Sj^n 1 ?

C

n ment data a1so shows nurcfcer of barrels in ca rbure to r ( s ) in the figure after the dash 440-4 Usually 4 barrels indicates the use of 2 carburetors. Metric equivalents of CID are as follows in liters: 360 (5.9), 401 (6.6), 360 (5.9), 440 (7.2), 351 (5.C), 460 (7.5) and 400 (6.6).

"STD" neans standard equipment on vehicles offered for police use. f'ay or may not be standard

on regular production models.

"M0" means an option that must be ordered (mandatory for a police car).

"SO" means available by special order, sometimes only if a minimum quantity is ordered.

"OPT" means available as regular production option.

Source: Specifications released by manufacturers in August 1974.

3 7
An analysis of the A. L. Craig survey of highway patrols

[8] completed in July 1973, table 7, shows that vehicle

specifications changed only slightly from the Bunten/Kl aus

survey. These changes reflect an increase in specifications of

the options, many of which have become standard on police

pursuit cars in 1974: automatic transmission, 8-cylindcr

engine, power steering, power brakes, front disc brakes, and

heavy-duty suspension (sec tables 5 and 6). The number of

departments specifying air conditioning did not change. This

is understandable since the states not specifying air

conditioning are located in the northern part of the country.

The picture that emerges of patrol cars in current use is as follows:

1. Standard-si ze 4 -door sedan with 8-cylinder engine,

automatic transmission, power steering, power brakes (front

disc), and heavy-duty suspension as standard equipment. Air

conditioning, tinted glass, and an interior hood release are

standard equipment for most departments. State agencies equip

most of their vehicles with trunk light and interior trunk

release. These larger vehicles, ''fully-equipped," are used

almost universally by State agencies and are largely preferred

by other departments except counties. Standard-size vehicles

account for only about 52 percent of county police cars.

2. Intermediate-size 4-door sedan equipped similarly to

the full-size sedan. While they represent over 20 percent of

the total fleet, the largest users are county and larger city

departmen ts

.

3. Station wagons appear to be largely special purpose,

i.e., emergency, rural patrol vehicles. They represent about 3

percent of the total fleet.

4. Compact-size cars appear to be used mostly by counties

and larger cities, but not the 50 largest. They represent

aijout one percent of the total fleet.

5. A trend to the use of s ub- compacts , i.e., 100-inch (254

wheel base or less, is under way, judging by news media

articles. The emphasis on fuel economy may accelerate this

trend. Indications are that some smaller residential

jurisdictions are having success with sub-compacts.

38.
Table 7 National Survey State Patrol Pursuit Cars

1972 - 1973

1 972 B!

%

1 973 [8]

%

Automatic Transmission 1 00 98

8-Cyl l nder Engi ne 1 00 94

Power Steering 100 90

Power Brakes 1 00 86

Disc Brakes 1 00 84

Heavy Duty Suspension 100 83

Air Conditioning 80 81

Tinted Glass 70 52

39.
While the preceding tabulation miqht indicate some

agreement on vehicle "design" which corresponds to the

requirements of a particular type of department, such is

definitely not the case. It is quite possible that no two

departments in the United States order exactly the same

vehicles for patrol purposes. These variations could be

interpreted in a number of ways:

1. Agencies know their performance requirements very well

and are tailoring the vehicle specifications to these

requi rements

,

2. Agencies do not know their requirements well and are

being "sold" certain vehicles,

3. Agencies use what ever information, data, or expertise

is available and specify based on exoerience,

4. Agencies are restricted in some measure by Dolicy,

funding, opinion, etc. to specifications and/or purchase

without regard to police requirements.

5. Trade-in value, low cost, maintenance cost, etc.,

rather than functional performance, may be over-riding

considerations in purchasing police vehicles.

Whatever the reason, the Bun ten/ Kl aus survey indicates that

patrol cars were considered to be the primary police equiDment

problem. Interviews and conversations with representatives of

police agencies and vehicle producers across the country tend

to confirm that confusion regarding a department's functional

requirements, and a lack of definitive data on vehicle

oerformance, are the real problems in obtaining the

functionally optimum patrol car for a particular jurisdiction.

For instance, the type of vehicle which apoears most suitable

for patrolling high speed highways hour after hour may not be

optimum for use in low speed patrolling of congested urban

areas or residential areas. Top sneed and acceleration are two

characteristics that should differ. Enaine cooling and

electricity generation under idle conditions are other

characteristics that may need to differ. Vehicle size nay be

another differentiating characteristic. While there is an

indication that some agencies are optimizing vehicle

configuration for functional patrol reoui rements , most are not.

40.
9. NEW DEVELOPMENTS

No industry is static--the automotive industry least of

all. In addition to i ndus try-qenera ted developments,

environmental considerations, safety, and energy conservation

are factors affectinq automobile development. In this section

we list some impacts, large and small, that may affect the

automobile in its role as a patrol car.

9.1 Pollution Control

Currently used approaches for meeting EPA standards are

going to continue to decrease horsepower. A study of the

literature and discussions with automobile industry

representatives reinforce the conclusion that the current

pollution control devices which have been added to the

reciprocating gasoline engine are interim measures which have

degraded the power output, dri veabi 1 i ty , and fuel efficiency of

the vehicle. Manufacturers are studying other annroaches to

meeting EPA emission requirements. Some of the potential

solutions under study include:

9.1.1 Stratified Charge Enqine

This is an internal combustion engine in which the

combustion chamber is divided into two parts. In the smaller

first chamber, the fuel to air ratio is high and combustion is

initiated. In the larger second chamber, the fuel to air ratio

is lowered by adding more air and combustion is completed. A

current example of this type of engine has been developed by

the Honda Motor Company of Japan, licensed to Ford and

Chrysler, and is being studied by General Motors. See fiqure

1 . 9.1.2 Wankel Rotary Engine

This engine, widely described in the literature, reportedly

can pass 1975 EPA standards, and with the addition of a relatively simple exhaust reactor can pass 107^ EPA standards.

This engine is currently proven in use but anoears at a disadvantage on fuel economy when compared with similar size

reciprocating engines. Rotary engines are relatively new and

improvements are likely to be made. See figure 2.

41 .
STRATIFIED CHARGE

o

Combustion in a stratified charge engine is much like cupping your hands to light a cigarette in the wind. A pre- combustion chamber tightly encloses all the elements necessary to start combustion: fuel delivered by an

injector, a small pocket of air and a spark from the nearby sparkplug. The initial mixture is very rich and easy to

ignite. As the charge burns, it moves out across the piston driving it down. Some unburned fuel is also driven

out of the small pocket and it mixes with additional air in the cylinder. This forms a fuel-air mixture that is pro- gressively leaner with increasing distance from the precombustion chamber. Hence the charge is "stratified"

(varying in fuel-air ratio). All other aspects of the engine are typical of current piston powerplants.

Figure 1

.

42.

Reprinted with permission

of "Car and Driver."
WANKEL

ROTOR

Instead of pistons and valves, the Wankel engine has one or more triangular rotors. They move through a combination of sliding and rotating motion determined by both an eccentric shaft and a reaction gear fixed to the

chamber's end plate. The true relationship between the rotor, the fixed gear and the eccentric shaft is shown

cutaway in view 2. The gear set is shown alone in view 1 . The eccentric shaft is illustrated separately in views 3

and 4. As the rotor moves to uncover the intake port, a fuel-air mixture isdrawn in (1,2,3,4) and the compressed

(5,6) before being ignited by the spark plug (7). The rapidly expanding gases created by combustion (7,8,9) drive

the rotor around the chamber, while delivering power to the eccentric shaft. The spent gases are then swept out

the exhuast port by the rotor (10,11,12,13). The process is continuous on all three sides of the rotor.

Figure 2,

43.

Reprinted with permission

of "Car and Driver."
9.1.3 Stirling Cycle Engine

This is an external combustion engine. Fuel is burned

outside the cylinders in which a working gas is sealed. The

heat expands the gas, which drives a piston to the opposite end

of the cylinder on the power stroke. On the return stroke, the

hot gas is pushed through a regenerator which removes some heat

to the lower chamber of an adjoininn cylinder. The cooled gas

is compressed by this second piston on its power stroke and

returned through the regenerator to the upper section of the

original cylinder where the gas is reheated and the cycle

repeated. See figure 3.

9.1.4 Diesel Engine

The only currently available di esel -nowered cars easily

pass 1975 EPA standards, but fail to meet the proposed 1976

standards. However, even Mercedes-Benz does not regard the

diesel as a viable alternative to the conventional gasoline

engine; the weight-to-power ratio and the cost of the diesel

are too high when compared to a gasoline engine of equal

horsepower. Diesel technology, however, has remained

essentially unchanged for many years, and it is unrealistic to

believe that further advances will not be made. See figure 4.

9.1.5 Gas Turbine

The gas turbine has been installed and tested primarily by

the Chrysler Corporation. The turbine dnes not oass 1975

emission standards and is on the lower side on fuel economy and

acceleration, important to patrol operations. Production costs

are a deterrent to broad acceptance. Chrysler Corporation has

recently reported improvements in turbine design which may

change the picture significantly. See figure 5.

9.1.6 Electric Engine

Small vehicles which operate on electric power are

available. Pollution, of course, is no problem, but speed and

range (50 mph [80 km/h] and 80 miles [130 km] per charge) make

the electric motor unacceptable for patrol use, except in

limited situations.
STIRLING CYCLE

The Stirling cycle engine is an example of external combustion: fuel is burned outside the engine to heat a working fluid sealed inside. A series of chambers are formed by the volume above one piston, interconnected to the volume below the next piston. These chambers are independent of one another and the working fluid re- mains sealed in each one. The two pistons move to change the total volume of the chamber and transfer the

fluid from the cold side below one piston to the hot volume above the next piston. As the gas is transferred, it passes through a regenerator that adds heat to the cold gas or removes it from the hot gas. But the bulk of the

heat flows from the continuous hot source above each piston. The axial reciprocating motion of the pistons is transformed into rotary motion by a "swash plate" that is solidly attached at an angle to the output shaft. Atotal

of four pistons produce the power and the following sequence of events occurs in one revolution of the Stirling

engine:

Between views 1 and 2, the pistons move from positions where the chamber volume is a maximum to the point

where the volume is a minimum, compressing the working fluid. Between 2 and 3, the cold, compressed fluid is pumped from beneath the right side piston through the regenerator, where it is heated, and into the volume

above the left piston. There has been no change in total chamber volume but heat from the source quickly raises

the pressure of gases above the left piston. This causes the gas to expand, driving the left piston down (between

views 3 and 4). This is the power stroke and the piston's downward motion forces the swash plate to rotate. Between views 4 and 1, the left piston pumps the working fluid through the regenerator, where some heat is removed, and back into the volume under the right piston. The cycle is then ready to repeat itself.

Figure 3.

Reprinted with permission

of "Car and Driver." 45.
DIESEL CYCLE

FUEL INJECTOR

O

Envision a conventional spark ignition engine with the spark plugs replaced by fuel injectors. The intake valve

delivers only air and the upward moving piston compresses it to such a high pressure and temperature that combustion is spontaneous the instant fuel is delivered by the injector. This combustion drives the piston down in the normal manner to deliver power to a crankshaft. The spent gases are then pumped out through a standard

exhaust valve.

Figure 4.

Reprinted with permission

of "Car and Driver."

46.
GAS TURBINE

OUTPUT SHAFT

In the gas turbine, a compressor wheel draws in air, compresses it and then pumps it through a regenerator

section. This rotating device is like a "heat sponge"- -it soaks up waste from the exhaust and delivers it to the air flowing in. A combustion chamber encircles the turbine's central shaft and here the compressed, heated air mixes with fuel and is ignited by a single spark plug device. Combustion is continuous with the exiting burning

gas displaced by additional air flowing in. The outgoing gases leave at temperatures near 1 700° F. to first drive a compressor turbine and then the main power turbine. The compressor turbine is connected directly to the compressor wheel, while the power turbine is linked only to the output driveshaft. After the hot gases have done their

work against the power turbine, they exit through the hot side of the regenerator. Here the spent gases relin- quish their heat prior to discharge into the atmosphere.

Figure 5.

Reprinted with permission

of "Car and Driver." 47.
9.1.7 Intake Valve Throttled Engine

In this internal combustion engine, there is no throttle

valve in the carburetor or intake manifold. Throttlinq is

obtained by varying the size of the intake valve opening by

means of a mechanical linkage. Extremely lean fuel-air

mixtures have been found to burn well over a wide range of

conditions. Consequently, this engine might be developed to

meet emission standards. Principal considerations appear to be

the complicated valve controlling mechanism and some loss in

fuel economy. See figure 6.

9.2 Fuel Efficiency

The need to conserve gasoline has prompted some departments

to experiment with fuel saving devices. One fuel savino

approach is the use of fuel additives designed to keen the

engine surfaces clean. Oil additives also fit in this

category. While such approaches to fuel saving have been

promoted for many years, the results in practice have often

appeared to fall short of the claims made. However, there is

no question that an engine operates more efficiently if it is

free of carbon and metallic deposits. The oil companies,

automobile manufacturers, and others continue to work on the

engine cleanliness problem.

Another approach to fuel conservation is to install screens

or other devices in the carburetor to improve the fuel/air

mixture and promote better combustion. Again, the claims for

these devices usually exceed the actual results. What are

lacking are valid methods of evaluation to provide guidance on

use of such additives and devices.

9.3 Brakes

The use of disc brakes on all four wheels is one

development that is expected to improve the performance of

patrol cars and possibly reduce one of the major areas of

complaint. Installation of disc brakes on the front wheels,

where 55 to 60 percent of the braking effort is accomplished,

has provided significant improvement in brake performance.

Conversion of the rear wheel drum brakes to disc brakes appears

to be under development by all manufacturers. While a few 1975

luxury models offer four wheel disc brakes, manufacturers claim

they are not satisfied with the current desinn for nroviding

the parking brake function. At present the arrangement

generally provides for a drum-tyne oarkinq brake inside the

rear disc brake rotors.

48.
INTAKE VALVE THROTTLED

In the intake valve throttled engine, there is no throttle valve in the carburetor or intake manifold. Instead, the

amount of fuel-air charge that enters the cylinder is controiled by varying the size of the intake valve opening. A

movable fulcrum connected to the throttle linkage slides along a rocker lever. This rocker lever transfers motion

from a camshaft and a pushrod to open the intake valve. The amount of motion transferred becomes intake valve

lift and depends solely on the position of the movable fulcrum. This engine is identical to current piston engines

in every other respect.

Figure 6.

49.

Reprinted with permission

of "Car and Driver."
Brake lining material is also under continuous development

to find better ways to dissipate the heat generated in braking.

Functionally, the brakes convert the kinetic energy of the

moving vehicle to heat energy. The effect of high temperatures

on organic brake lining is to reduce the coefficient of

friction of the surface of the lining in contact with the brake

drum or disc. This causes the brake to fade. However,

metallic linings become more effective at high temperatures

because their coefficient of friction increases as the brake

temperature increases. On the other hand, at low temperatures

the coefficient of friction between the organic material and

the brake surface is higher than that of the metallic material.

An additional factor, which is considered objectionable for

police operations, is the noise generated by the sliding

contact of the metallic lining on the metallic brake surface.

These factors have led to general use of so-called semimetallic brake linings for patrol cars. This material consists

of metal particles bonded with resin and appears to represent a satisfactory compromise between the desirable and undesirable

properties of the other two materials.

The most effective braking is obtained when the tire-toroad friction is the greatest, which occurs at approximately 15

percent wheel slip between the tire and the road surface. This

may be visualized as the condition existing when the road speed

of a vehicle is 100 mph (160 km/h) and the wheels are turning

at a rate equivalent to 85 mph (135 km/h). This means that of

the energy being absorbed in stopping the vehicle, 85 percent

is absorbed in the brakes and 15 percent is absorbed at the

tire-road interface. Locking the wheels to prevent their

rotation forces all the stopping energy to be absorbed at the

tire-road interface, making braking performance highly

dependent on road surface condition and effectively eliminating

steering control. These relationships can be seen in figure 7,

where the braking effectiveness (curve A) is seen to peak at

about 15 percent wheel slip. Controllability (curve E) is

shown to approach zero as the vehicle nears 100 percent wheel

slip ( 1 ocked wheels).

One system that is designed to improve brake action is the

antilock brake which acts to limit or prevent wheel lock-up.

The device works by sensing wheel lock-up and immediately

reducing line pressure on the brake shoe or pad to permit wheel

rotation to resume. For a reasonably proficient driver, in a car with well-balanced brakes, antilock provides an advantage

on all roads, but especially on wet or icy road surfaces,

according to a study funded by DOT. [11] It should be pointed

out that a number of current police specifications for patrol

cars require that the brakes can be locked, which automatically

rules out use of antilock brakes, even though the feature may

be desirable.

50.
1.0

7. Relationship of wheel slip to braking and controllability.

51 .
Another approach that is being studied is variable

proportioning of braking pressure. In this system, the braking

load is sensed by a mechanical measurement of the distance

between the axle and the body, or by measuring the deceleration

of the vehicle. From this measurement, the pressure can be

proportioned between the front and rear brakes to better

balance total braking action.

9.4 Tires

New developments in tires for patrol cars appear to center

on improvements in tire construction and the use of new

materials. Tires made with Kevlar are being put on the market

in 1975. The specifications for these Kevlar belted tires call

for a high speed capability of 125 mph (200 km/h) for sustained

periods. The use of radial tires appears to be increasing

because of the improved handling, gas mileage and tread wear

which they seem to provide.

9.5 Safety Regulations

While the intent and effect of the Federal Motor Vehicle

Safety Standards have been to reduce the risk of injury to

automobile occupants, some of the newer standards appear to

pose some problems in police use of vehicles. The National

Highway Traffic Safety Administration is becoming aware of the

problems posed by some of the standards in police patrol

operations, but little has been done so far to alleviate these

problems. Police agencies are beginning to make their special

problems and requirements known and actions have been proposed

to provide relief from certain standards which appear to

excessively restrict police vehicle operations.

On the other hand, there is mounting evidence that police

vehicles may require special consideration under Federal motor

vehicle safety standards. It should be evident to anyone who

has ever ridden in a patrol car that the special equipment

mounted in the front seat area exposes the occupants to

additional risk during a collision. Knobs, buttons, and

handles protrude from radios, speed measuring instruments and

spotlights; shotguns are often mounted vertically in special

racks; radio control heads and lamps present sharp, unpadded

edges. These potential hazards require additional evaluation

and special attention.

52.
9.6 The Special Police Vehicle

A subject of recurring discussion is the so-called "super

police car." The concept generally suqgests that all of the

best existing automotive technology be incorporated into a vehicle that would provide the most desirable characteristics

for all the functions required of patrol cars. While

automotive engineers and designers might come close to

designing such a vehicle, a great deal of difficulty can be

anticipated in providing in one vehicle the varying

requirements perceived by different types of police

departments. In fact, the urban and the highway patrol

reauirements appear so different that possibly at least two

designs might be required.

Tne greatest deterrent to the "super police car" is

probably cost. The present market for "police enuipped" cars

is about 65,000 per year at an average of about $3500 each, or

a net cost of $2500 with trade-in. If these vehicles were

produced in a special factory instead of on the standard

automotive production lines, the cost estimates range from

$20,000 to $40,000 per vehicle, with the possibility there

would be no trade-in value because of the special

characteristics of the vehicles. Moreover, repair and

maintenance of these vehicles miqht present serious problems

for most departments.

The potential advantages of a specially designed patrol

car, as well as some of the disadvantages cited above, seem to

dictate that at least a feasibility study should bp made. This

study should develop quantitative criteria, explore alternate

approaches to meeting the criteria, and provide a cost/benefit

analysis.

10. VEHICLE FLEET MANAGEMENT

Much has been written about the acquisition, maintenance,

and disposition of vehicles that are operated as a fleet.

While it is important that the patrol car fulfills as nearly as possible the patrolman's functional requirements for

transportation, it is equally important that the vehicle be

available to the patrolman when he needs it. This availability

perhaps can be loosely described as the function of fleet

management. The important function of police fleet management

is thoroughly discussed in a study by Rosalie T. Ruegg prepared

for the Law Enforcement Assistance Administration by the Law

Enforcement Standards Laboratory of the National Bureau of

Standards [9].

53.
11. SUMMARY

Considering that the basic function of a patrol car is to

provide transportation for the patrolman, the vehicles

currently available are reasonably adequate, particularly if

the law enforcement agency elects to use the vehicles offered

by the manufacturers as "police cars."

Problems do exist in using currently available automobiles

for patrol purposes. Some of the more apparent problems

include the following:

1. The automobile industry seems to be headed to the

production of smaller vehicles. While some departments are

converting a portion of their fleets to these smaller cars,

others are reluctant to depart from the use of the full-size

sedan, in spite of the economic advantages involved.

2. Police agencies need vehicles that provide certain

performance characteristics. The agencies lack performance

criteria, hence they write design specifications to indirectly

specify the performance requirements when purchasing patrol

cars

.

3. Many of the needed test methods for measuring performance

are lacking, or at best rudimentary.

4. Information on tires, specifically oriented to police

requirements, is not readily available to departments, except

from tire companies.

5. Certain aspects of patrol car performance are being

reduced, i.e., speed, acceleration, and gasoline mileage, while

at the same time maintenance costs are increasing.

6. Some of the Feoeral Motor Vehicle Safety Standards appear

to run counter to the operational needs for police patrol. For

instance, the seat belt interlock system probably served

to increase the emergency response time. On the other hand,

special safety standards for patrol cars appear to be justified

for protection against the many additional handles, knobs, and

other sharp or protruding objects commonly found in a police

car

.

In summarizing the state of the patrol car art, one could

very well come to the conclusion that there is no such special

vehicle; that police are driving, as one patroln.an claimed,

"the same cars that are used in taxi cab fleets." Perhaps some

patrolmen are; some patrolmen are also using standard passenger

vehicles.

54.
Upon closer scrutiny, however, one reaches the conclusion

that vehicles specifically intended for the patrol car function

are available and are widely used. These vehicles are found to

be structurally reinforced and equipped with heavy duty

subsystems deemed necessary by the manufacturer to better

endure police patrol use. It seems fair to say these changes

and modifications have been developed primarily to imnrove the

capability of these vehicles for high speed pursuit. This, of

course, has led to large engines, a need for special, high

speed tires, and a sacrifice in operating economy and

maintenance costs.

Whether the user requirements of the many and varied police

agencies have been adequately met by the vehicles provided is

open to question, and the manufacturers would be the first to

agree. When one considers that there are between 19,00 n and

24,000 police agencies, each with its own set of purchase

specifications, buying from essentially only four automobile

manufacturers, one might ask how the patrol car has achieved

any distinct characteristics at all. To the extent this has

been accomplished, credit must be given to those

representatives of the automotive manufacturers and the police

community who have recognized the problems and attempted to

solve them over the years.

Despite these efforts to provide a "patrol car," the

conclusion is inescapable that currently available products arp

not adequately meeting all police renin remen ts . About 2^

percent of vehicles used for patrol are not those the

manufacturers offer as "patrol cars." There are problems with

the inability of users to quantify their needs and to

communicate them to the producer. Production technology has

not yet provided solutions to the user's unique reaui remen ts

Herein lies the challenge: can performance-oriented

guidelines, tests, and standards be developed for police patrol

cars that will satisfy the functional requirements of

individual agencies and that, at the same time, can be met by

vehicle manufacturers at a reasonable cost?

55.
APPENDIX- -REFERENCES

1. Brostron, C . , "Strategy and Tactics," Police Patrol

Readings, Samuel G. Chapman, editor, (Thomas, Springfield,

Illinois, 1970) p. 151.

2. Ludwig, H. G., "Study of the Police Patrol Vehicle," Wayne

State University, College of Engineering, February 1971.

3. Wynne, G. R. , "Police Transportation Management," (Coda,

Studio City, California, 1965).

4. Bunten, E. D. and Klaus, P. A., LESP-RPT-0007 . 00 , "LEAA

Police Equipment Survey of 1972, Volume VII: Patrolcars,"

Department of Justice (in press).

5. Planek, T. W. , et al . , "The Development of an Injury and

Damage Reduction Function for Municipal Police," National

Safety Counci 1 , 1971 .

6. Baumeister, Theodore, "Standard Handbook for Mechanical

Engineers," 7th edition, (McGraw-Hill, 1967).

7. Ervin, R. D., et. al., "Vehicle Handling Performance,"

Highway Safety Research Institute, Ann Arbor, Michigan,

November 1972.

8. Craig, A. L., "National Survey State Patrol Pursuit Cars,"

North Carolina Highway Patrol, Raleigh, North Carolina,

1973.

9. Ruegg, Rosalie T. , LESP-RPT-0402 . 00 , "Life Cycle Costing of

Police Patrol Cars," U. S. Department of Justice, October

1974 ( i n press )

10. Pfefferkorn, R. G., "Patrol Car Vehicle Emission Control,"

Problem Investigation Report, ID Number ILEAA-01, Mitre

Corporation, May 1973.

11. Murphy, Ray W., "A Procedure for Evaluating Vehicle Braking

Performance, Highway Safety Research Institute, Ann Arbor,

Michigan, October 1971, DOT HS 800 628.

12. Collard, Jared J., "Report on an Investigation of the ligh

Speed Hazards of Steel Belted Radial Tires on Police

Patrol Cars," National Bureau of Standards, May 1975

(in press).

56.
NBS-114A (REV. 7-73)

U.S. DEPT. OF COMM. BIBLIOGRAPHIC DATA

SHEET

1. PUBLICATION OR REPORT NO. NBS IR 75-960

2. Gov't Accession

No.

3. Recipient's Accession No.

4. TITLE AND SUBTITLE

rPKf» Pol 1 PP P = -t-rTtl far • Q+- a ^ -f J-U,-. A v+-

5. Publication Date NOVEMBER 1975

6. Performing Organization Code

7. AUTHOR(S)

R. G. Masssy

8. Performing Organ. Report No.

9. PERFORMING ORGANIZATION NAME AND ADDRESS

NATIONAL BUREAU OF STANDARDS

DEPARTMENT OF COMMERCE

WASHINGTON, D.C. 20234

10. Project/Task/Work Unit No. 4409380

11. Contract/Grant No.

12. Sponsoring Organization Name and Complete Address (Street, City, State, ZIP)

National Institute of Law Enforcement and

Criminal Justice, LEAA

Department of Justice

Washington, D.C. 20531

13. Type of Report & Period Covered

Final

14. Sponsoring Agency Code

15. SUPPLEMENTARY NOTES

16. ABSTRACT (A 200-word or less factual summary of most significant information. If document includes a significant

bibliography or literature survey, mention it here.) This report, entitled "The Police Patrol Car: State of the Art" describes the functional requirements of police agencies for patrol

cars, the manner in which these requirements are met, or not met, by vehicles currently in use, and a discussion of new automotive

technology which might affect patrol car performance in the future.

17. KEY WORDS (six to twelve entries; alphabetical order; capitalize only the first letter of the first key word unless a proper name; separated by semicolons) Functional requirements; patrol cars; performance of patrol cars; police patrol cars; problems with patrol cars; state of the art survey

18. AVAILABILITY r_2 Unlimited 19. SECURITY CLASS

(THIS REPORT)

21. NO. OF PAGES

1 X For Official Distribution. Do Not Release to NTIS

UNCLASSIFIED

56

1 Order From Sup. of Doc, U.S. Government Printing

Washington. D.C. 20402. SD Cat. No. C13

Office 20. SECURITY CLASS

(THIS PAGE)

22. Price

[ ! Order From National Technical Information Service

Springfield, Virginia 22151

(NTIS)

UNCLASSIFIED

USCOMM-DC 29042-P74