HAWASSA UNIVERSITY

INSTITUTE OF TECHNOLOGY

SCHOOL OF CIVIL ENGINEERING

MASTER OF SCIENCE IN ROAD AND TRANSPORTATION ENGINEERING

TRAFFIC SAFETY AND ENVIRONMENTAL IMPACTS

PROPOSAL ON:

ASSESSMENT OF SPEED AS ONE OF THE BEHAVIORAL RISK FACTORS

Submitted by;
Name of candidate ID. No.
1. Tola Aliyi………………………………………………..…….......................PGRo/041/09
2. Zerihun Belayneh…….…………………………. ………….……………... PGRo /049/09
3. Seid Diltata…………..………………………………….…………………. PGRo /033/09
4. Mohammed Mukter …………….……………………...…………………. PGRo /025/09
5. Mulugeta Regassa …………………………………...……………… PGRo /029/09

Submitted to: Dr. Ashenafi A.

: Mr. Mandefro

January, 2018.
 ABSTRACT

In theory, speed plays a role in every road crash: if everybody were to stand still, there would be
no traffic. However, it is very difficult to determine the number of crashes in which too fast
speeds was the main cause. In addition to speed, there often are various other factors involved
that play a role in a crash occurring. In any case: the risk of a crash occurring is greater as
speeds get higher; this is one of the reasons that speed limits are set. However, this does not
mean that ‘keeping to the limit’ is always safe. This proposal contain background, statement of
the study, objectives of the study, literature review, How does speed affect traffic crash and
injury, Factors affect speed, Relation between speed and crash severity, Measurement taken to
overcome the effects of speed, research methodology, Budget Estimation.
Keywords:-Cause, Control, Effectiveness

IV
 ACKNOWLEDGMENT

First of all we would like to thank Hawassa University Institute Of Technology school of Civil
Engineering. Next, we would like to send our deepest gratitude to our course Instructor Ashenafi
Aregawi (PhD) and seminar advisor Mr. Mandifro for their excellent advice and guidance with
professional approach by providing and helping us with their knowledge and an appropriate
information.

III
 TABLE OF CONTENTS

Title Pages

Acknowledgment……………………………………………………………………………I

Abstract…………………………………………………………………………….………..II

1. Introduction…………………………………………………………………….………...1

1.1 Background of the study……………………………………....…………….…….……..1

1.2 Statement of the problem…………………………………………………………....…...1

1.3 Research Questions………………………………………………………………………2

1.4 Objectives of the study……………………………………………………..…….………2

2. Review of Literature………………………………….………...…………….….……….3

2.1 Introduction………………. ………………………………………..…….….………...…3

2.2 How does speed affect traffic crash and injury?.................................................................5

2.3 Factors affect speed……………………………………………………………………….6

2.4 Relation between speed and crash severity………………….……………………………6
2.5 Measurement taken to overcome the effects of speed….…………………………………7

3. Methodology and procedure…………………………..……………….……….…….….9

3.1 study area…………………………………………………………………………………9

3.2 source of data……………………………..…..………….……………………...…..……9

3.3 procedure of data collection………………….………………………….………..………9

4. Budget Estimation………………………………………………………………………..10

List of Tables
Table1: Requested items and break downs………………………………………………….10

Table 2: Schedule of Activities………………………………………………...…………..11

i
List of Figures.

Figure 2.4.1 the relation between speed and crash rate ………………………………………7

Figure2.5.1 Conventional countermeasures to speed…………………………………………8

Reference…………..…………………………...……………………..…….…………….…12

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 CHAPTER ONE
INTRODUCTION
1.1 Background
Speed has been identified as a key risk factor in road traffic injuries, influencing both the risk of
a road crash as well as the severity of the injuries that result from crashes. Excess speed is
defined as exceeding the speed limit. Inappropriate speed is defined as driving at a speed
unsuitable for the prevailing road and traffic conditions [7].

Excess and inappropriate speeds are responsible for a high proportion of the mortality and
morbidity that result from road crashes. In high-income countries, speed contributes to about
30% of deaths on the road, while in some low-income and middle- income countries, speed is
estimated to be the main contributory factor in about half of all road crashes. Controlling vehicle
speed can prevent crashes happening and can reduce the impact when they do occur, lessening
the severity of injuries sustained by the victims [2].

Severity is particularly critical for vulnerable road users such as pedestrians and cyclists. For
example, pedestrians have been shown to have a 90% chance of survival when struck by a car
travelling at 30 km/h or below, but less than 50% chance of surviving an impact at 45 km/h.
Pedestrians have almost no chance of surviving an impact at 80 km/hr. Pedestrian fatality risk as
a function of the impact speed of a car [3].

Speed is also dangerous if it is higher than the circumstances at that moment allow (e.g. because
of rain, fog or large traffic volume). In general, this inappropriate speed in particular is difficult
to determine objectively. Therefore the police rarely register speed as the crash cause. It is
generally assumed that about one third of fatal crashes are (partly) caused by speeding or by
inappropriate speed (OECD/ECMT, 2006) [5].

1.2 statement of the problem

The aim of Studying speed as behavioral risk factors is that to reduce the traffic injuries and
death concerning it. Speed is one of the leading behavioral risk factors which cause traffic
accidents that face to different crash types (fatal crash, serious crash, slight crash and damage).
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1.3 Research Questions
The research study tries to address the following research questions.

How does speed affect traffic crash and injury?

What factors affect speed?
What can be done to manage the adverse effects of speed?
What is the relation between speed and crash severity?

1.4 Objective of the Study

1.4.1 General objective

 Investigating behavioral risk factors particularly effects of speed on traffic accidents
which lead to different crash types
1.4.2 Specific objective
 How does speed affect traffic crash and injury
 Factors affect speed.
 Relation between speed and crash severity.
 Measurement taken to overcome the effects of speed

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 CHAPTER TWO
LITERATURE REVIEW
2.1 Introduction
There is an acute need for an economic system for remotely controlling and limiting the speeds
of vehicles traveling at speeds above the road's speed limit. The related art of interest describes
various speed control systems, but none discloses the present invention.

The related art will be discussed according to its perceived relevance to the present invention.

U.S. Pat. No. 5,135,295 issued on May 24, 1994, to Yutaka Fujii describes a vehicle speed
control system used with a vehicle navigation system that provides information relating to the
road being traveled on, including curves on the road. Sign-mounted transmitting devices send
signals to the vehicle navigation system that will activate throttle and brake controls to
automatically slow the vehicle if it is traveling at an unsafe speed to handle the upcoming curve
or if the vehicle is above the posted speed limit. The intricate system is distinguishable for its
automatic braking control, temperature sensors, magnetism sensors, alarms, and reliance on
global positioning satellite system access.

U.S. Pat. No. 5,771,007 issued on Jun. 23, 1998, to Toshiaki Arai et al. describes an auto-cruise
system for a vehicle comprising transmitters placed along a highway that take control of a
vehicle's cruise control system. The transmitters detect the oncoming vehicle's speed and
activates an audible warning and brake and throttle control circuits to slow the vehicle to the
posted speed until the vehicle travels out of the transmitter's range. The system is distinguishable
for its reliance on the vehicle's auto-cruise system for the transmitted control of an audible
warning and brakes control of a speeding vehicle.

Japan Patent No. 6-36187 issued on Feb. 10, 1994, to Hiroshi Sekine describes a speed controller
system which is a self-contained road navigation system for a vehicle that provides an alarm and
automatic braking/throttle control when a vehicle is approaching a curve in the road at an unsafe
speed. The system is distinguishable for its alarm and automatic braking system limited to
curved roads.

U.S. Pat. No. 5,819,198 issued on Oct. 6, 1998, to Gilboa Peretz describes a dynamically
programmable automotive-driving monitoring and alarming device and system, wherein the
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transmitters mounted on a corner of traffic signs, not traffic lights as in the present invention,
transmit the encode speed limit to the vehicle's alarm system which records and sounds an
audible alarm with a library of digitized voice messages. The system is distinguishable for its use
of transmitters on traffic signs, the recording of speed in the vehicle's computer and sounding an
audible descriptive alarm in the vehicle.

U.S. Pat. No. 5,420,794 issued on May 30, 1995, to Robert D. James describes an automated
highway system for controlling the operating parameters of a vehicle. A vehicle is detected by
the highway system by a transponder on the vehicle responding to an omni-directional radio
frequency transmission from a highway control facility. The highway control facility interrogates
the vehicle transponder for identification, destination, inter alia, to route the vehicle, schedule
maintenance and provide user services. The facility calculates the location of the vehicle and
energizes vehicle mounted actuators to steer, accelerate and brake the vehicle as necessary. The
vehicle has a user interface unit whereby the driver can be informed of road, weather and traffic
conditions. The user interface unit also permits communications by voice (microphone and
loudspeaker), keypad, and CRT. The automated highway system is distinguishable for
automating the steering, acceleration and braking of the vehicle.

U.S. Pat. No. 5,742,240 issued on Apr. 21, 1998, to Nobuyoshi Asanuma et a. describes a travel
control unit for a vehicle passing through a curved road comprising a map information outputting
device, a vehicle position outputting device, a travel control device for controlling the speed, and
an alarm device which when activated would stop the travel control device when the vehicle
deviates from the set course in a curve. A deviatable course determining device and the travel
control device can then control the speed in negotiating the curve. The travel control unit is
distinguishable for its emphasis on negotiating a curved road automatically.

U.S. Pat. No. 5,784,005 issued on Jul. 21, 1998, to Eisaku Akutsu et al. describes a
communications infrastructure system for vehicles comprising a plurality of beacons on a road
transmitting repeated series of at least three kinds of signals. The vehicle has a receiver for
receiving the beacon's signals, a unit for discriminating the kind of signal, a memory for
recording a past record of the kind of signal, and a signal generator generating a signal
corresponding to the past record. The system is distinguishable for emphasizing a system for

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identifying the vehicle's position on an up lane or a down lane for resolving traffic problems
during an accident.

U.S. Pat. No. 5,805,057 issued on Sep. 8, 1998, to Firooz B. Eslaminovin describes a remote
vehicle disabling and distress indicator system for a vehicle activated by an external telephone
call or internally by a switch. The telephone call sends a signal which is received by the vehicle's
modular telephone and the vehicle is disabled by deactivating the ignition coil or closing the fuel
valve. A distress sign on the vehicle top is illuminated and a tape machine plays a prerecorded
distress message. The system is distinguishable for its disabling function.

Japan Patent No. 54-55923 issued on May 4, 1979, to Hiroyasu Fukaya describes an apparatus
for safety control of a vehicle negotiating a curved road. A road transmitter communicates with
the vehicle's microcomputer to signal the vehicle of the allowable speed for negotiating the
curve. The microcomputer sounds an alarm buzzer if the posted speed limit is exceeded by the
vehicle. The apparatus is distinguishable for being limited to an audible warning signal in the
vehicle.

None of the above inventions and patents, taken either singularly or in combination, is seen to
describe the instant invention as claimed. Thus, an economical speed limit control system which
utilizes existing illuminated traffic signs is desired.

2.2 How does speed affect traffic crash and injury?

The higher the speed of a vehicle, the shorter the time a driver has to stop and avoid a crash.
A car travelling at 50 km/h will typically require 13 metres in which to stop, while a car
travelling at 40 km/h will stop in less than 8.5 metres. An increase in average speed of 1 km/h
typically results in a 3% higher risk of a crash involving injury, with a 4–5% increase for crashes
that result in fatalities. Speed also contributes to the severity of the impact when a crash does
occur. For car occupants in a crash with an impact speed of 80 km/h, the likelihood of death is 20
times of 30 km/h. An average increase in speed of 1 km/h is associated with a 3% higher risk of
a crash involving an injury[7].

In severe crashes, the increased risk is even greater. In such cases, an average increase in speed

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of 1 km/h leads to a 5% higher risk of serious or fatal injury. Travelling at 5 km/h above a road
speed limit of 65 km/h results in an increase in the relative risk of being involved in a casualty
crash that is comparable with having a blood alcohol concentration of 0.05 g/dl. For car
occupants in a crash with an impact speed of 80 km/h, the likelihood of death is 20 times what it
would have been at an impact speed of 30 km/h. Pedestrians have a 90% chance of surviving car
crashes at 30 km/h or below, but less than a50% chance of surviving impacts at 45 km/h or
above. The probability of a pedestrian being killed rises by a factor of 8 as the impact speed of
the car increases from 30 km/h to 50 km/h [4].

2.3 Factors affect speed

Drivers’ speed choice is influenced by a number of factors that can be considered as; driver
related factors (age, gender, alcohol level, number of people in the vehicle); those relating to the
road and the vehicle (road layout, surface quality, vehicle power maximum speed); traffic and
environment related (traffic density and composition, prevailing speed, weather conditions) [7].

The speed of motor vehicles is at the core of the road traffic injury problem. Speed influences
both crash risk and crash consequence. The physical layout of the road and its surroundings can
both encourage and discourage speed [1].

2.4 Relation between speed and crash severity

The relation between speed and safety rests on two pillars. The first pillar is the relation between
Crash speed and the severity of a crash; the second pillar is the relation between speed and the
risk of a crash. The higher the crash speed, the more serious the consequences in terms of injury
and material damage. This is a law of physics that involves the quantity of kinetic energy that is
converted in an instant into e.g. heat and matter distortion. In addition, the human body is
physically very vulnerable in comparison with the enormous forces released in a collision.
During the past decades, vehicles have become ever better equipped (with crush areas, airbags
and seatbelts) to absorb the energy released in a crash, thus protecting the occupants. However,
the collision speed still is very important for the crash outcome [2].

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The second pillar of the relation between speed and safety concerns the risk of a crash. The faster
a car is driven, the higher the risk of being involved in a crash. This is partly due to the longer
braking distance and partly to the fact that the human being is limited in its capacity to process
information and act on it. It must be noted, however, that the relation between speed and crash
rate is much less direct and much more complicated than the relation between speed and crash
severity. Relatively many studies have examined the relation between absolute speed and crash
rate. Irrespective of the research method used, practically all the studies concluded that the
relation between speed and crash rate can best be described as a power function: the crash rate
increases more rapidly when the speed increases and vice versa (Figure 2).

Figure 2.4.1 Diagram showing the relation between speed and crash rate, © SWOV,
Leidschendam, the Netherlands April 2012

2.5 Measurement taken to overcome the effects of speed

Speeding has been long recognized as a major factor in severity of car accidents and it can be
considered as primary contributor to fatal crashes [6].In an attempt to reduce speeds on
roadways, engineering methods as well as enforcement, education have assisted in reducing
speeds at urban section of the roads[6].Engineering methods includes road facilities like speed
cameras, regulatory signs, warning signs, flagging control for speed reduction, pavement
markings and dynamic variable message sign for speed reduction have been used[4].

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Responsive to local conditions and traffic circumstances, and are therefore more likely to be
kept. The speed limit for cars and motorcycles in towns and villages is 30-50 km/h and outside
towns 100 km/h [3]. Pavement markings as a perceptual countermeasure have been used to
reduce driver’s speeds. It’s one of the methods to help road users to slow down at relatively low-
cost and its more effective on curves [6].

Dynamic variable message sign can be either post mounted or placed on a trailer. The sign is
equipped with radar to determine the speed of approaching vehicles and consequently displays
input messages. For example, a driver who complies with the posted speed limit will receive a
“Thanks” message. The sign, however, displays a “You are speeding” message to a speeding
vehicle [6].

This paper proposed some perceptual techniques for speed reduction on urban streets and this
proposal will contribute toward safe road environment in the near future. However, speed
cameras are very expensive and dynamic variable message sign method is also difficult to apply
in urban streets. So we proposed regulatory signs, warning signs and flagging control and they
can be effective in urban sections of the road.

Figure2.5.1 Conventional countermeasures to speed (source MUTCD, 2001).

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 CHAPTER THREE
METHODOLOGY AND PROCEDURE

This proposal is conducted by Hawassa University Road and Transport Engineering Masters of
Science students to investigate speed as one of behavioral risk factors which cause traffic
accidents that lead to different types of crash (fatal crash, serious crash, slight crash and
property damage).

3.1 Study Area

We are not requested to specific area to do this proposal. For this reason we had done our
proposal depending on policy implementation by different bodies or scholars on the speed, which
is one of the behavioral risk factors that cause traffic accidents.

3.2 Sources of Data

Data used for this proposal is secondary data ( i.e by browsing different scholars those well
discussed about speed, which cause crash above speed limit.

3.3 Procedure of Data Collection

First, identifying the source of data required.

Then, collecting the information required from the source.
Finally, analyzing the data and making general conclusion and inferences based on collected
data.

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 4. BUDGET ESTIMATION

Table1: Requested items and break downs.

Items Unit of Quantity Unit Total Cost

cost(Birr)
Measurement (Birr)
1. Main costs
1.1. Payment for flagging man Number 10 2,500.00 25,000.00
1.2. Circular steel posts, 50mm Dia, Number 65 600.00
1.5mm thick 39,000.00
1.3. Iron sheet, 1.5mm thick Number 10 1,000.00 10,000.00
1.4. Printing press Number 130 250.00 32,500.00
1.5. Uniform cloths for flagging man Number 30 200.00 6,000.00
1.6. Flag made of clothes and wooden Number 30 50.00
post 1,500.00
1.7. Payment for traffic police Number 4 5,000 20,000.00
Sub-total 134,000.00
2. Stationary and other supportive expenses
2.1. Papers Pad 5 150.00 750.00
2.2. Pens/pencils Number 50 5.00 250.00
2.3. CD/Flash disk Number 5 100.00 500.00
2.4. Communication expenses Day 30 125.00 3,750.00
2.5. CDMA router Number 1 950.00 9,50.00
2.6. CDMA recharge balance Number 5 200.00 1,000.00
2.7. Transportation cost Day 30 50.00 1,500.00
2.8. Photocopy, print and document Number 5 100.00
binding 500.00
Sub-total 9,200.00
Total Sum(I & II) 143,200.00
Contingency (10%) 14,320.00
Grand Total 157,520.00

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 SCHEDULE OF ACTIVITIES

Table 2. Schedule of Activities

September

November
October
August
March

April

June
May

July
S/No Research activity
1. Searching of related literatures books
journals, internet browsing and others

2. Collection of questionnaire, Data

collection and Data processing (tabulation
of collected data)
3. Deciding where regulatory signs, warning
signs and flagging control for speed
reductions are needed.
4. Posting regulatory and warning signs and
positioning of flagging mans and traffic
police.
5. Combine all results and writing 1stdraft of
final paper
6. Writing final draft of the research thesis

7. Presentation of the paper

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References;

1. Getu Segni, Causes of Road Traffic Crash and Possible Counter Measures on Addis
Ababa-Shashemene Roads, April 2007
2. Mercy JA et al. Public health policy for preventing violence. Health Affairs, 1993:7–
29.5. Haddon Jr W. Advances in the epidemiology of injuries as a basis for public
policy. Public
3. Muhlrad N, Lassarre S. Systems approach to injury control. In: Tiwari G, Mohan D,
Muhlrad Health Report, 19[80, 95:411–421.
4. MUTCD, Application of the Manual on Uniform Traffic Control Devices for Streets and
Traffic Control Devices for Streets and Highways, 2001.
5. N, eds. The way forward: transportation planning and road safety. New Delhi,
Macmillan India Ltd., 2005:52–73 Organization, 2004.
6. Proposal of Pavement Markings by Jonghak Lee, 2311, Daehwa-dong, Ilsan-gu, Goyang-
si, Gyeonggi-do, 411-712, Republic of Korea.
7. World Health Organization (Who), Global Status Report on Road Safety: Time for
Action, 2009

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