EVALUATION ON THE PERFORMANCE OF SIGNALISED …

EVALUATION ON THE PERFORMANCE OF SIGNALISED

ROUNDABOUT AT BULATAN SEKSYEN 15, BANDAR BARU

BANGI, SELANGOR

MUHAMMAD DANIAL BIN ROSLI

UNIVERSITI TEKNOLOGI MALAYSIA

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SIGNATURE OF STUDENT SIGNATURE OF SUPERVISOR

970627-14-5295

IR. DR. SITTI ASMAH BINTI

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MATRIX NUMBER NAME OF SUPERVISOR

Date: 30 MAY 2020 Date: 30 MAY 2020

“I hereby declare that we have read this thesis and in my

opinion this thesis is suffcient in term of scope and quality for the

award of the degree of Bachelor of Engineering (Civil)”

Signature : ________________________________

Name of Supervisor : IR. DR. SITTI ASMAH BINTI HASSAN

Date : 30 MAY 2020

EVALUATION ON THE PERFORMANCE OF SIGNALISED ROUNDABOUT

AT BULATAN SEKSYEN 15, BANDAR BARU BANGI, SELANGOR

MUHAMMAD DANIAL BIN ROSLI

A thesis submitted in fulfilment of the

requirements for the award of the degree of

Bachelor of Engineering (Civil)

School of Civil Engineering

Faculty of Engineering

Universiti Teknologi Malaysia

May 2020

ii

DECLARATION

I declare that this thesis entitled “Evaluation on The Performance of Signalised

Roundabout at Bulatan Seksyen 15, Bandar Baru Bangi, Selangor” is the result of

my own research except as cited in the references. The thesis has not been accepted

for any degree and is not concurrently submitted in candidature of any other degree.

Signature : ....................................................

Name : MUHAMMAD DANIAL BIN ROSLI

Date : 30 MAY 2020

iii

DEDICATION

To my parents.

Thank you for all the support and encouragement.

To my supervisor, Ir. Dr. Sitti Asmah binti Hassan.

Thank you for your guidance, advice, and support given in completing this

study.

To all my friends who assisted me in completing this study.

For all your assistance and support will always be remembered.

To all staff of Road Department at JKR Daerah Hulu Langat.

Thank you for the guidance and help given in completing this study.

iv

ACKNOWLEDGEMENT

First and foremost, all grateful and thanks to Allah S.W.T, the Lord of the

Universe, the most gracious and merciful on blessing.

I wish to express my sincere appreciation to my supervisor, Ir. Dr. Sitti

Asmah binti Hassan, for all the encouragement, guidance, and support. Without her

continued support, this thesis would not be the same as presented here.

My sincere appreciation also extends to all staff of Road Department and

Maintenance Department at JKR Daerah Hulu Langat, who have provided assistance

at various occasions. Their views and advices are useful in guiding me to finish this

thesis. Unfortunately, it is not possible to list all of them in this limited space.

And lastly, to my family members that always support me morally, I am

grateful to received such kind support from them.

v

ABSTRACT

Road network is really important in human daily life as they use it to access

from place to place. It is really important to make an assessment on road

performance to keep the traffic moving as smoothly as possible. In Bulatan Seksyen

15, Bandar Baru Bangi, drivers have to wait for a long time before they can enter the

roundabout due to traffic congestion. This study aims to evaluate junction

performance at signalised roundabout in Bulatan Seksyen 15, Bandar Baru Bangi.

Traffic volume and signal indication at the roundabout were obtained for two

weekdays for 14 hours from 6am to 8pm. The data was collected using manual

counting technique. Morning and evening peak volume were used in analysing the

level of service (LOS). The data was analysed to obtain control delay using

guidelines in Arahan Teknik Jalan 13/87. In this study, it was found that the traffic

approaches of the signalised roundabout experienced level of service in a range of D

and E which indicates unstable flow. It was suggested that the traffic signal system at

the roundabout to be changed to ramp metering or unsignalised system.

vi

ABSTRAK

Rangkaian jalan adalah sangat penting dalam penggunaan harian manusia

kerana penggunaannya untuk bergerak dari satu tempat ke tempat yang lain.

Penilaian ke atas prestasi jalan adalah sangat penting bagi memastikan trafik

bergerak selancar yang mungkin. Di Bulatan Seksyen 15, Bandar Baru Bangi,

pemandu perlu menunggu dengan lama sebelum mereka boleh memasuki bulatan

tersebut oleh kerana kesesakan yang berlaku. Kajian ini bertujuan untuk menilai

prestasi di bulatan berisyarat di Bulatan Seksyen 15, Bandar Baru Bangi. Jumlah

trafik dan petunjuk lampu isyarat di bulatan diperolehi untuk dua hari kerja selama

14 jam dari jam 6 pagi sehingga 8 malam. Pengumpulan data bagi kajian adalah

menggunakan pengiraan secara manual. Jumlah kenderaan pada waktu pagi dan

petang telah dipilih bagi menganalisa tahap perkhidmatan dalam rangkaian. Data

dianalisa untuk mendapatkan kelewatan kawalan menggunakan garis panduan yang

telah ditetapkan di dalam Arahan Teknik Jalan 13/87. Kajian ini telah mendapati

bahawa arah kemasukan trafik di bulatan berisyarat mengalami tahap perkhidmatan

di dalam skala D hingga E yang menunjukkan aliran tidak stabil. Adalah

dicadangkan supaya sistem isyarat trafik di bulatan ditukar kepada meter tanjakan

atau sistem tidak berisyarat.

vii

TABLE OF CONTENTS

TITLE PAGE

DECLARATION ii

DEDICATION iii

ACKNOWLEDGEMENT iv

ABSTRACT v

ABSTRAK vi

TABLE OF CONTENTS vii

LIST OF TABLES x

LIST OF FIGURES xi

LIST OF ABBREVIATIONS xii

LIST OF SYMBOLS xiii

LIST OF APPENDICES xiv

CHAPTER 1 INTRODUCTION 1

1.1 Background of Study 1

1.2 Problem Statement 2

1.3 Aim and Objectives of the Study 3

1.4 Scope of Study 3

CHAPTER 2 LITERATURE REVIEW 4

2.1 Introduction 4

2.2 Traffic Volume 4

2.2.1 Method to Determine Traffic Volume 5

2.2.1.1 Manual Counting 5

2.2.1.2 Automatic Count Devices 5

2.2.1.3 Video Recording 6

2.3 Type of Junction 7

2.3.1 Signalised Junction 8

2.3.2 Unsignalised Junction 8

viii

2.3.2.1 Two Way Stop Controlled (TWSC) 8

2.3.2.2 All Way Stop Controlled (AWSC) 10

2.3.2.3 Roundabout 11

2.4 Delay 12

2.5 Level of Service 13

2.5.1 American Approach 13

2.5.2 Australian Approach 13

2.5.3 Malaysian Approach 14

2.6 Ramp Metering 15

2.7 Analytical and Simulation Delay 18

2.7.1 Analytical Delay 18

2.7.2 Simulation Delay 20

2.7.2.1 SIDRA INTERSECTION 20

2.7.2.2 VISSIM 21

2.8 Summary 21

CHAPTER 3 RESEARCH METHODOLOGY 23

3.1 Introduction 23

3.2 General Framework 23

3.2.1 Site Selection 25

3.2.2 Identification of the Required Data 26

3.2.2.1 Field Geometry 26

3.2.2.2 Traffic Data 26

3.2.2.3 Traffic Signal Indication 26

3.2.3 Data Collection 27

3.2.4 Data Extraction 28

3.2.5 Data Analysis 29

3.2.6 Result and Discussion 30

CHAPTER 4 RESULT AND ANALYSIS 31

4.1 Introduction 31

4.2 Traffic Volume 31

4.3 Traffic Composition 41

ix

4.4 Delay and Level of Service 45

4.5 Chapter Summary 51

CHAPTER 5 CONCLUSION AND RECOMMENDATION 52

5.1 Introduction 52

5.2 Findings 52

5.2.1 Objective 1: To determine the traffic characteristic in

term of volume and composition 52

5.2.2 Objective 2: To determine the control delay at

signalised roundabout 53

5.2.3 Objective 3: To determine the level of service

(LOS) of each approaches 53

5.3 Recommendation for Future Works 53

REFERENCES 54

x

LIST OF TABLES

TABLE NO. TITLE PAGE

Table 2.1 LOS criteria for signalised junction 14

Table 2.2 LOS criteria for signalised roundabout 15

Table 2.3 LOS criteria for signalised junction 15

Table 2.4 Minimum requirement LOS for Malaysia Road 16

Table 3.1 Level of Service 29

Table 4.1 Vehicle volume per 1 hour interval from Persiaran Kemajuan to

Persiaran Pekeliling 33


Roundabout 34

Table 4.3 Vehicle volume per 1 hour interval from Persiaran Pekeliling to

Persiaran Wawasan 35


Roundabout 36

Table 4.5 Vehicle volume per 1 hour interval from Persiaran Wawasan to Tol

Bangi 37

Table 4.6 Vehicle volume per 1 hour interval from Persiaran Wawasan to

Roundabout 38

Table 4.7 Vehicle volume per 1 hour interval from Tol Bangi to Persiaran

Kemajuan 39

Table 4.8 Vehicle volume per 1 hour interval from Tol Bangi to Roundabout 40

Table 4.9 Summary of traffic composition 44

Table 4.10 Summary of current delay for AM peak hour 46

Table 4.11 Sumary of current delay for PM peak hour 46

Table 4.12 Actuated signal timing for Persiaran Pekeliling 46

Table 4.13 Actuated signal timing for Persiaran Wawasan 46

Table 4.14 Actuated signal timing for Tol Bangi 47

xi

LIST OF FIGURES

FIGURE NO. TITLE PAGE

Figure 2.1 Traffic stream at a four-leg TWSC junction 10

Figure 2.2 Traffic stream at a T-leg TWSC junctionError! Bookmark not defined.

Figure 2.3 Difference between freeway with ramp metering and

freeway without ramp metering 16

Figure 2.4 Ramp metering at roundabout 17

Figure 3.1 General Framework 24

Figure 3.2 Study Area 25

Figure 3.3 Manual traffic count at Bulatan Seksyen 15, Bandar Baru Bangi 27

Figure 3.4 Excel Form 28

Figure 4.1 Junction layout 32

Figure 4.2 Traffic composition at Bulatan Seksyen 15, Bandar Baru Bangi 41

Figure 4.3 Traffic composition from Persiaran Kemajuan to the roundabout 42

Figure 4.4 Traffic composition from Persiaran Pekeliling to the roundabout 42

Figure 4.5 Traffic composition from Persiaran Wawasan to the roundabout 43

Figure 4.6 Traffic composition from Persiaran Tol Bangi to the roundabout 43

Figure 4.7 Traffic volume at morning peak hour 44

Figure 4.8 Traffic volume at evening peak hour 45

Figure 4.9 Current level of service for signalised roundabout 47

Figure 4.10 LOS for unsignalised approaches for AM peak hour by using

SIDRA INTERSECTION 48

Figure 4.11 LOS for unsignalised approaches for PM peak hour by using

SIDRA INTERSECTION 49

Figure 4.12 LOS for ramp metering by using SIDRA INTERSECTION 49

xii

LIST OF ABBREVIATIONS

ATJ - Arahan Teknik Jalan

LOS - Level of Service

AWSC - All-Way-Stop-Controlled

TWSC - Two-Way-Stop-Controlled

HCM - Highway Capacity Manual

xiii

LIST OF SYMBOLS

d - Delay

S - Saturation flow

λ - Proportion of the cycle that is effectively green for the phase

x,X - Degree of saturation

C - Cycle length

g - Effective green

P - Proportion of vehicles arriving on green

𝑓PA

T

k

I

Q

c

𝑥0

sg

-

-

-

-

-

-

-

-

Supplement adjustment factor for platoon arriving during

green

Duration of analysis period

Incremental delay factor that is dependent on controller

settings

Upstream filtering/metering adjustment factor

Lane group capacity

Capacity

Degree of saturation below which the second term delay is

zero

Capacity per cycle

xiv

LIST OF APPENDICES

APPENDIX TITLE PAGE

Appendix A Data Collection Table 54

1

CHAPTER 1

INTRODUCTION

1.1 Background of Study

The analysis of transportation system is an important research as it concerns

the daily activities of millions of people moving within the city (Fancello, 2014). An

evaluation of transport network functionally has been widely studied. In general, the

studies quantify road network performance by means of key performance indicator

that represents the functionality of the network from a specific aspect. Some

investigation focuses on the quality of the traffic flow such as the ability to keep

traffic moving as smoothly as possible, using indicators that depend on the

geometrical characteristic: travel time, delay at junction and traffic flow (TRB,

2010).

Junction performance can be measured by determining the volume of

vehicles in certain period, identifying the level of service and the signal indication to

figure out the period of delay at road junction. In the transportation system, traffic

light is the vital component for the effectiveness of the traffic movement. The design

of the red, amber and green time must consider the volume, delay, accident

experience and geometrics. Increase of traffic intensity leads to situation when it

becomes impossible to provide a satisfactory level of traffic servicing with the help

of only traffic light signaling means. Congestion at a section of the road traffic

network with traffic signals is a situation when the average duration of the vehicle

delay exceeds the length of the traffic signaling cycle.

Signalised junction indicate to drivers when to enter the junction, thus

removing the problem for intuitive selection of safe gaps in the traffic flow. This in

turn minimizes the probability of crashes between the turning vehicles and oncoming

through traffic. Signalised junctions work on the premise that motorists at the stop

line are given right of way at the onset of effective green. However, when

approaching a signalised junction at high speeds and the light turns yellow it may be

difficult for the driver to discern whether they should run the yellow light or brake to

2

be safe. If the inter-green time is too short, only those vehicles that are close to the

junction will be able to continue through the junction safely. Signalised junction

should allow any vehicle, regardless of its location, to be able to safely stop or,

alternatively, safely proceed during the inter-green period.

This is done by making sure that any vehicle closer to the intersection than its

minimum braking distance can safely proceed through the junction without

accelerating or speeding. As an alternative, signalised roundabout can be installed.

However, roundabout is not the ultimate solution for road congestion. The quality of

service will started to decline as the traffic volume keep increasing by years until the

capacity of the roundabout cannot accommodate the traffic.

Highway Capacity Manual (HCM) developed by the transportation research

board of USA provides some procedure to determine level of service. The level of

service have been divided into six classes which is class A to class F. class A

represents the best performance of traffic where the traffic density will be low, with

no interruption flow speed control by driver desire, low volume, and the drivers

maintain their desire speed with little or no delay. Level F shows the worst quality of

traffic where the demand exceeded the capacity of the road.

1.2 Problem Statement

Due to the traffic growth, major problem which is traffic congestion started to

take place on several roads around Bandar Baru Bangi especially during peak hour

where people drive to work and back from work. One of the congested area is

Bulatan Seksyen 15 where it connects the main road from the residencies area and

Plaza Tol Bangi. Bulatan Seksyen 15 has shown a poor performance in term of

traffic movement where the traffic inside the roundabout moves very slowly thus

creating a long queue length from approaching lanes during peak hour. Even though

the roundabout has already been installed with traffic signal system which is semi-

actuated traffic lights at 3 approaches, it still cannot solve the congestion problem.

Thus, an assessment needs to be done on the roundabout in order to identify this

congestion problem.

3

1.3 Objectives

The aim of the research is to evaluate the signalised roundabout performance at

Bulatan Seksyen 15, Bandar Baru Bangi. To achieve the aim, this study is based on

the following objectives:

1. To determine the traffic characteristic in term of volume and composition.

2. To determine the control delay at signalised roundabout.

3. To determine the level of service (LOS) of each approaches.

1.4 Scope of Study

The scope of the study includes the process of determining the performance

at the signalised roundabout at Seksyen 15 Bandar Baru Bangi. The parameters that

were determined to assess the roundabout performance are traffic volume, signal

indication, and delay time. This study only takes into consideration of the signalised

approaches which is from Persiaran Kemajuan, Persiaran Pekeliling, and Tol Bangi

approaches of the Bulatan Seksyen 15.

4

CHAPTER 2

LITERATURE REVIEW

2.1 Introduction

In order to fulfill the objectives requirement, problem statement, and scope of

study, this chapter will describes several literature reviews. This literature review

will go through different methods to conduct data collection as well as all the

variables used in order to estimate the capacity and delay of the signalised

roundabout.

2.2 Traffic Volume

Traffic volume studies are conducted to determine the number, movements,

and classification of roadway vehicles at given location. These data will be used to

help determine the influence of large vehicles or pedestrian on vehicular traffic flow,

identify critical flow time period, or document traffic volume trends. The duration of

the sampling period depends on the type of count being taken and the intended use of

the data recorded. However, the count duration should avoid special event or

compromising weather condition (Sharma, 1994). Count duration typically are 15

minutes or 2 hours for peak periods, 4 hours for morning and afternoon peaks, 6

hours for morning, midday, and afternoon peaks, and 12 hours for daytime periods

(Robertson, 1994). These data can be used to determine the traffic composition, as

well as predicting the future traffic volume. This is essential for many applications,

including planning for maintenance and real-time traffic control improvements.

5

2.2.1 Method to Determine Traffic Volume

2.2.1.1 Manual Counting

Manual counting method is the most common method of collecting traffic

flow data which consist of assigning a group of people to record traffic as it passes.

Manual counts are typically used for duration of less than a day, and is not suitable if

it exceed a day. By using this method, it is possible to obtain data which cannot be

collected by mechanical counters, such as vehicles classification, turning

movements, and number of vehicles at intersections. However, field observations

require large group of people depending on the size of the study data needed. The

size of data collection team depends on the length of the counting period, the type of

count being performed, the number of lanes or crosswalk being observed, and the

volume level of traffic (Robertson, 1994). A manual count study includes three key

steps:

i. The aim of the manual count will be reviewed during the preparation.

This will help to determine the number of observers required, the field

procedure to follow, and the type of equipment need to be used.

ii. Observers must be positioned where they have a clear view of the traffic

but at the same time provide safety during the manual counting. The

observers may have the best point if they are positioned above the ground

level and clear of obstructions.

iii. Manual counts may produce a large number of data forms. If order to

keep the data forms organized, labelling must be done on all the data

forms. On each tally sheet, the observers should record the location, time

and date of the observation, and weather conditions.

2.2.1.2 Automatic Count Devices

Automatic count is deployed in cases where manual count method cannot be

implemented. In this method, vehicles are counted automatically without any human

involvement. Due to its function, this method can gather a large amount of data for a

6

longer period of time which may extend up to a week, month, or year (Chakravorty,

2015). Various instruments or equipment can be used for automatic count, which has

their own benefits and barriers. Some of the most widely used instruments are:

i. Pneumatic tubes

These are tubes that are mounted on top of road surface at location where

traffic counting is required. As vehicles pass over the tube, the resulting

compression sends a burst of air to an air switch, which will then be send

to a recorder that was installed by the road side.

ii. Inductive loops

Inductive loop detector consists of embedded turned wire. It includes an

oscillator, and a cable, which allows signals to pass from the loop to the

traffic counting device. Inductive loops are cheap, almost maintenance-

free and are currently the most widely used equipment for vehicle

counting and detection.

iii. Micro-millimeter Wave Radar detectors

Radar detectors actively emit radioactive signals at frequencies ranging

from the ultra-high frequencies (UHF) of 100MHz to 100GHz, and can

detect vehicular presence and speed. Thus, it can detect vehicular

volumes and classifications in both traffic directions.

iv. Piezo-electric cable

A sensing strip made from a metallic cable which responds to a vertical

loading from vehicle wheels passing over it by producing a corresponding

voltage. The cable is very good for speed measurement and axle-space

registration, and is relatively cheap in maintenance.

2.2.1.3 Video Recording

Video recording in traffic count refers to a method where a video recorder is

set up at the study area where the traffic is visible to the recorder. Video recording

has the perks to greatly simplify traffic data collection, saves time, reduce

requirement for field staff, and accurately record traffic without missing a movement

(Davies, 2011). Data collection methods using manual counting and automatic

counting devices are generally single-purposed, while video-based systems are much

7

more adaptable to different study types. Video-based systems are more efficient for

data collectors due to its versatility of data that can be extracted from the video.

Video recording method could produce a more accurate and detailed data

collection. This is because data collectors can count vehicles from pre-recorded

videos taken from traffic-monitoring cameras. Data collectors can pause, stop, and

replay the video at their convenience. This would reduce the probability of missing

data such as vehicles miscount which can happen when observing on the field due to

fatigue of the observers. This method also allows cross-checking where a different

data collector can review the video and correct any mistake made from the previous

users. This would reduce the error in the data counting that would have exist in

manual counting method where cross-checking could not be done unless two

counters were deployed at the observation point.

Despite the notable benefits of using video recording for traffic counting,

there have been some issues of using this method. One of the issues is the convenient

location to set up the video recorder. A consideration that should be taken during the

setup of the video recorder is not only focus on getting a good view but also security,

access, and in case of long survey, availability of power supply (Taylor et al., 2000).

2.3 Types of Junction

According to Arahan Teknik (Jalan) 11/87, junction is defined as area where

two or more roads cross or meet. Junctions are an important part of the road system

where their capacity controls the volume of traffic within the network system. When

more than one movement interacts, maneuver will occurs. Multiple maneuvers

should be avoided as they confuse drivers. Generally, there are two types of junction

which are used in design:

i. Signalised junction

ii. Unsignalised junction

8

2.3.1 Signalised Junction

At individual junction, a safe and efficient traffic flow must be provided by

allocating a traffic signal to ensure the traffic can run smoothly. On a network where

conflicts usually occur, a traffic signal is essential to eliminate the conflicting traffic

movements. Three signal indications are displayed (red, green and yellow). Red

indication means the road user should stop to give way to other approaches to pass

through the junction.

2.3.2 Unsignalised Junction

Unsignalised junction is the most common intersection type. Although their

capacities may be lower than other intersection types, it plays an important part in the

control of traffic in a network (Troutbeck, 1997). There are three types of

unsignalised junction which is two way stop controlled (TWSC), all way stop

controlled (AWSC), and roundabouts.

2.3.2.1 Two Way Stop Controlled (TWSC)

This junction is commonly used in the United States and abroad. To control

vehicles movement, stop signs were used at the junction. At TWSC junction, the stop

signs are located at the minor road approaches. If the junction is not controlled by a

stop sign, it is considered as major street approaches.

The priority of right-of-way given to each stream as stated by the Highway

Capacity Manual is used to mitigate conflicting traffic problems. Some streams have

absolute priority, whereas others have to give way or yield to higher-order streams.

Figure 2.1 and Figure 2.2 below show the relative priority of streams at both T-leg

and four-leg junctions. The figures illustrate traffic system of the United States of

America which is based on the left-hand drive. By convention, subscripts 1 to 6

define vehicle movements on the major street, and subscripts 7 to 12 define

movement on the minor street. Subscripts 13 to 16 define the pedestrian movements.

9

Figure 2.1 Traffic stream at a four-leg TWSC junction (HCM2000)

Figure 2.2 Traffic stream at a T-leg TWSC junction (HCM2000)

10

Movement of Rank 1 gives right-of-way to any through or right-turning

vehicle on the major street. Through and right-turning movements from the major

street have the highest priority at the TWSC junction. Movement of Rank 2 includes

vehicles turning left from the major street to the minor street and also right-turning

from the minor street to the major street. Movement of Rank 3 includes through

traffic from the minor street (in case of four-leg junction) and left-turning traffic

from the minor street (in case of T-leg junction). Lastly, movement of Rank 4

includes traffic turning left from the minor street.

2.3.2.2 All Way Stop Controlled (AWSC)

This junction, like TWSC junction, is widely used in the United States of

America and other countries in North America. All-ways stops function best when

the traffic volume at the intersection is high enough that vehicle conflicts are

common and when the traffic volume is evenly split between the intersecting streets

(Celniker, 1989). At this junction, the stop sign are located at all four approaches

which require all vehicles to stop.

While stopping at the stop line, drivers need to make judgement whether to

proceed into the junction according to the rules of AWSC junction. The rules of

AWSC junction are as follow:

1. The first vehicle to arrive at the junction receives the right-of-way. The

vehicles arriving after the first vehicle needs to wait for the first vehicle to

proceed.

2. When two vehicles arrive at the junction at the same time and are located

side-by-side, the vehicle on the right has the right of way.

3. When arriving at the junction head-to-head with another vehicle, the vehicle

going straight has the right of way than the vehicle turning left or right.

4. When two vehicles arrive head-to-head at the junction at the same time, and

both of the vehicles intend to turn to the same direction, the vehicle turning

right has the right of way.

According to FHWA, approximately 72 percent of fatal crashes occur at

unsignalised junction, and the most often factor of these crashes are due to drivers’

failure to yield the right of way.

11

2.3.2.3 Roundabout

At roundabout, traffic travels clockwise around a central raised island, and

entering traffic must yield to circulating traffic. According to ATJ 11/87, a

roundabout may be applicable as an option for intersection when the total traffic

volume from all directions is up to 6000 vehicles/hour. The size of roundabout varies

depending on the traffic demand at the intersection.

i. Mini – less than 20m in diameter of inscribed circle, less than 4m in

diameter of center circle

ii. Small – 20m to 50m in diameter of inscribed circle, 4m to 15m in

diameter of center circle

iii. Conventional – more than 50m in diameter of inscribed circle, more than

25m in diameter of center circle

However, roundabout design requires a larger land space in order to cater for

approaches of every intersection. But since the approaches are free flow

unsignalised, roundabout can have more than four legged intersection. The

roundabout can be signalised once it exceeds the capacity of 6000 vehicle/hour per

leg, if it is so required (ATJ 11/87 Amendment 2016). A roundabout design can also

accommodate for future expansion or upgrade if any of it approaches reach its

saturation capacity level, that is by converting the roundabout into an interchange

such as flyover or ramp to relief the traffic congestion for the particular approach

inside the roundabout.

12

2.4 Delay

Delay is one of the parameter to measure the operational quality or

effectiveness of signalised junctions. According to AASHTO, delay is defined as the

additional travel time experienced by a driver, passenger, or pedestrian due to

circumstances that impede the desirable movement of traffic. According to Mathew

T. V. in his journal Signalised Intersection Delay Model, the most frequently used

forms of delay is defined as follows:

• Stopped Time Delay

Stopped time delay is defined as the time a vehicle is stopped in queue while

waiting to pass through the intersection. It begins when the vehicle is fully

stopped an ends when the vehicle begins to accelerate. Average stopped time

delay is the average for all vehicles during a specified time period.

• Approach Delay

Approach delay includes stopped time delay but adds the time loss due to

deceleration from the approach speed to a stop and the time loss due to re-

acceleration back to the desired speed. Average approach delay is the average

for all vehicles during a specified time period.

• Travel Time Delay

It is the difference between the drivers’ expected travel time through the

intersection (or any roadway segment) and the actual time taken. To find the

desired travel time to traverse an intersection is very difficult. So this delay

concept is rarely used except in some planning studies.

• Time-in-queue Delay

Time-in-queue delay is the total time from a vehicle joining an intersection

queue to its discharge across the stop line on departure. Average time-in-

queue delay is the average for all vehicles during a specified time period.

Time-in-queue delay cannot be effectively shown using one vehicle, as it

involves joining and departing a queue of several vehicles.

• Control Delay

Control delay is the delay caused by a control device, either a traffic signal or

a stop-sign. It is approximately equal in time-in-queue delay plus the

acceleration-deceleration delay component.

13

2.5 Level of Service

Level of service (LOS) is a quality measure describing operational conditions

within a traffic stream, in terms of such service measures as speed and travel time,

freedom to maneuver, traffic interruptions, and comfort and convenience (TRB,

2000). There are six LOS defined for each type of facility that has analysis

procedures available. Letters designate each level. From A to F, with LOS A

representing the best operating condition and LOS F the worst. Each level of service

represents a range of operating condition and the driver’s perception on those

conditions.

2.5.1 American Approach

The average control delay per vehicle is estimated for each lane group and

aggregated for each approach and for the intersection as a whole. LOS is directly

related to the control delay value. According to HCM2000, Table 2.1 shows the

classification of level of service for signalised junction as follow:

Table 2.1 LOS criteria for signalised junction

LOS Control Delay per Vehicle (s/veh)

A ≤ 10

B > 10-20

C > 20-35

D > 35-55

E > 55-80

F > 80

2.5.2 Australian Approach

The classification of this approach is similar to American approach for

signalised intersection. However, SIDRA which is originated from Australia

highlighted the level of service classification for signalised roundabout (Akcelik,

2009). Table 2.2 shows the level of service classification for signalised roundabout

as follow:

14

Table 2.2 LOS criteria for signalised roundabout


A ≤ 10

B > 10-20

C > 20-35

D > 35-50

E > 50-70

F > 70

2.5.2 Malaysian Approach

According to Arahan Teknik (Jalan) 11/87, the control delay per vehicle is

used as a measure of the level of service and this is a measure of driver discomfort,

frustration, fuel consumption, and lost travel time. The traffic forecast for any

junction design must fulfill the minimum requirement of level of service according to

the type of road and maintained throughout the forecasted year as mentioned in ATJ

11/87 in Table 2.4. Table 2.3 shows the level of service classification for signalised

junction as follow:

Table 2.3 LOS criteria for signalised junction


A < 5

B 5.1 to 15.0

C 15.1 to 25.0

D 25.1 to 40.0

E 40.1 to 60.0

F > 60.0

15

Table 2.4 Minimum requirement LOS for Malaysian Road

Areas Category of Road Level of Service

Rural

Expressway

Highway

Primary

Secondary

Minor

C

C

D

D

E

Urban

Expressway

Arterial

Collector

Local Street

C

D

D

E

2.6 Ramp Metering

Ramp meters are traffic signals which can be found on freeway on-ramps to

regulate the rate or frequency of vehicles entering the freeway (Yang, 2019). Ramp

meter is a simple traffic signal where there is only two indication, red and green. At

metered ramps and under normal ramp metering control condition, the approaching

vehicles have to stop at the metering signal before the metering signals turns green.

The vehicles are then released individually into the mainline, often at a rate that is

dependent on the mainline traffic volume and speed at that time.

Ramp metering reduces overall freeway congestion by managing the amount

of traffic entering the freeway and by breaking up platoons that make it difficult to

merge onto the freeway (FHWA, 2017). In high traffic volume, ramp meters can

reduce stopped time delay even when considering time in queue on the ramp. By

allowing for smooth merging maneuvers, collision on the freeway can be avoided.

Without ramp meters in operation, multiple vehicles merge in tightly packed

platoons, causing drivers on the mainline to slow down or even stop in order to allow

vehicles to enter. This condition would lead to potential congestion and collision on

the mainline. Sensors are installed on both the freeway and the ramp to observe the

traffic stream condition and provide information to the metering system.

16

Sensors on the freeway consist of detector loop which will detect the gap

between vehicles and provide a green light indication on the ramp meter controller to

allow a vehicle to pass through and merge smoothly into the mainline. There are two

types of sensors that are installed on the ramp which is the demand sensor and end of

queue sensor. Demand sensor feed information to the ramp meter controller on

vehicle presence on the ramp while the end of queue sensor is placed at the entrance

of the ramp to prevent backups onto local streets by releasing the queue when the

ramp reaches maximum capacity. Figure 2.3 shows the difference on freeway when

ramp metering is placed.

Figure 2.3 Difference between freeway with ramp metering and freeway without

ramp metering

Other than freeway, ramp metering can also be installed at roundabout that is

having traffic congestion. A metering signal is a traffic light, used in high volume

areas, which regulates the number of vehicles passing a certain point (Mosslemi,

2008). In the case of roundabouts, the metering signal is the signal that is being

17

controlled to create gaps in flowing traffic. The traffic output can be greatly

improved by operating metering signals at roundabouts which have uninterrupted

entry flows from some approaches.

The problem of unbalanced traffic flows can be resolved by a metering signal

installed on a high-volume roundabout approach by momentarily detaining drivers at

the entrance. It offers motorists the opportunity to enter the flowing highway at the

other approaches. Roundabout metering signals are often built on a part-time basis on

selected approaches, because they are only needed during heavy demand situations

during peak hour (Akçelik, 2006). It is important to consider the selection of the

metered approach and controlling approach correctly.

Metered approach is the entry at which red signals stop the traffic. This is the

approach that creates problems because of an uninterrupted traffic flow for its

preceding entrance. The preceding approach is commonly called the controlling

approach. Detectors are typically mounted in the controlled approach and are

attached to the metering signal for real-time monitoring. Figure 2.4 shows the typical

ramp meter installation at a roundabout.

Figure 2.4 Ramp metering at roundabout

18

2.7 Analytical Delay and Simulation Delay

Delay is the most important measure of effectiveness at a signalised junction

because it relates to the amount of lost travel time, fuel consumption, and the

frustration and discomfort of drivers (Akgungor & Bullen, 2014). Delay also can

compare the performances of an intersection under different control, demand and

operating conditions. The accurate prediction of delay is, therefore, very important,

but its accurate estimation is difficult due to random traffic flows and other

uncontrollable factors. Delay can be estimated by measurement in the field,

simulation, and analytical models. Of these methods, analytical estimation is the

most practical and convenient.

2.7.1 Analytical Delay

Many stochastic steady-state delay models use the assumptions that arrivals

are random and departure headways are uniform but these assumptions are

impractical in general (Akgungor & Bullen, 2014). Stochastic steady-state delay

models are only valid for under-saturated conditions and predict infinite delay when

the power exceeds the arrival flows. The deterministic models for this are more

practical for predicting delay for over-saturated conditions, but these models ignore

the effect of randomness in traffic flow.

Time-dependent delay models were developed to overcome the shortcomings

in both stochastic steady state and deterministic delay models. Using the coordinate

transformation method, these models combine stochastic steady state and

deterministic models. They have models of delay which are more practical.

There are three different time dependent delay models (Australian, Canadian

and the Highway Capacity Manual (H.C.M.)) commonly used to estimate delay at

signalised junctions. There is a delay parameter k in all of these models that is fixed

but this k parameter and does not account for the effects of variable traffic demands

and variable time periods of analysis.

The H.C.M. delay model provides reasonable results for under-saturated

conditions but predicts higher delays for over-saturated conditions compared with

19

other delay models. With increasing degree of saturation the difference between the

H.C.M. delay model and other delay models increases. Hence it is not advised to

delay calculations for higher values. The H.C.M. delay model has been derived for a

time period of 15 minutes and hence, the estimation of delay using this model is

limited to time periods of 15 minutes duration.

The level of delay at a signalized intersection is a function of many

parameters including the capacity, the traffic volume, the amount of green time

available, the degree of saturation, the analysis time period, and the arrival patterns

of vehicles. H.C.M. prescribes delay per vehicles (s/veh) as;

……Equation 1

Akcelik has derived the Australian delay model which is an approximation to

Miller’s delay model. The Australian delay model predicts zero overflow delay

before the overflow delay term is applied for low degrees of saturation. The

minimum degree of saturation value depends on capacity per cycle, and a symbol 𝑥𝑜

is given. The Australian model for delay is expressed as follows:

𝑑 = C(1−λ)2

2(1−λ𝑥)+ 900𝑇[ (x-1)+√(𝑥 − 1)2 + 12(

𝑥−𝑥0

𝑐𝑇) ] …………………… Equation 2

and

𝑥𝑜 = 0.67 + 𝑠𝑔

600 ………………………………………………………….. Equation 3

The Canadian delay model which was derived by Whiting is commonly

applied to predict delay at signalised junction. Like other time-dependent delay

models, the model consists of two terms that have uniform and overflow delay

terms.. The Australian and Canadian delay models have a similar structure, but

different coefficients in the overflow delay term. After some revision, the Canadian

delay model is expressed as follows:

20

𝑑 =C(1−λ)2

2(1−λ𝑥)+ 900𝑇[ (x-1)+√(𝑥 − 1)2 + (

4𝑥

𝑐𝑇) ] ………………….……. Equation 4

2.7.2 Simulation Delay

Road traffic congestion comprises of several complex procedures and

incorporates numerous components cooperating simultaneously. Improving traffic

signal timing and coordination is one of the most widely used method to relieve

congestion and enhance mobility of traffic. In such problem condition, a simulation

model can be a very effective tool as it provides evaluations for various traffic

condition (Ismael et al., 2018).

Simulation models are useful tools that enable the traffic engineer to model

real-life traffic conditions without disrupting everyday operations. Simulation

models are also a low cost alternative to actual field implementation of traffic

improvement measures. Theoretical improvements can be modeled before they are

introduced in highway applications to obtain the best course of action in a given

scenario. In a sense, they enable the traffic engineer to improve driving conditions

by a trial and error method that will reduce delay to a minimum.

One of the issues that can arise from using traffic modeling packages is how

well does the package model a given traffic condition (Benekohal et al., 2001).

Some users may prefer a specific modeling program in all cases, others may use a

different program because it has a user-friendly interface. In either case, the results

obtained from the simulation may not be what actually occurs in the field. It may be

true that software previously accepted as able to provide accurate modeling may in

truth not be applicable to a particular traffic situation. There are several software for

traffic performance analysis such as Highway Capacity Software, Synchro,

SimTraffic, VISSIM, and SIDRA.

2.7.2.1 SIDRA INTERSECTION

SIDRA INTERSECTION is a software used as an aid for design and

evaluation of individual intersections and networks of intersections. It can be used to

21

analyse signalised intersections (fixed-time / pretimed and actuated), signalised and

unsignalised pedestrian crossings, roundabouts (unsignalised), roundabouts with

metering signals, fully-signalised roundabouts, two-way stop sign and give-way /

yield sign control, all-way stop sign control, single point interchanges (signalised),

freeway diamond interchanges (signalised, roundabout, sign control), diverging

diamond interchanges. It can also be used for uninterrupted traffic flow conditions

and merge analysis.

SIDRA INTERSECTION was first released in 1984 and has been under

continuous development in response to user feedback. In February 2017, the latest

versions of the software were in use by about 1930 organizations with about 8200

licenses in 84 countries. The countries where SIDRA INTERSECTION was used

most extensively were USA, Australia, Europe, New Zealand, South Africa, Canada,

Malaysia and Singapore.

2.7.2.2 VISSIM

VISSIM is a microscopic, behavior-based multi-purpose traffic simulation to

analyze and optimize traffic flows (Barcelo, 2010). It offers a wide variety of urban

and highway applications, integrating public and private transportation. VISSIM was

developed by PTV Planung Transport Verkehr AG in Karlsruhe, Germany in 1992. It

can be used for the analysis and evaluation of road traffic.

At present, in the fields of the urban roads, highways, and integrated transport

system, VISSIM is one of the most common software (Zhou et al., 2014). VISSIM

simulation software includes individual vehicles, and has a detailed definition of the

vehicle travel behavior, tracking and record. Therefore, it can more accurately

calculate the vehicle delay.

2.8 Summary

Junction performance is an important measure as it is part of traffic system

components. In this study, the signalised roundabout will be evaluated in order to

ensure whether it serve a good performance or otherwise. The parameter that is

22

needed to measure the performance of the signalised roundabout is traffic volume,

signal indication, and delay. Manual counting was chosen as the method to carry out

traffic count. Level of service based on Arahan Teknik Jalan 11/87 was used to

estimate delay at the roundabout based on the parameters stated.

23

CHAPTER 3

RESEARCH METHODOLOGY

3.1 Introduction

This chapter describes the method to carry out the study. The main objective

of the study is to evaluate the performance of signalised roundabout by determining

the level of service of the road. The study was started with identifying the problem,

which is expressed as problem statement. The second step was setting the objectives

of the study. Then, based on the targeted objectives, literature review of the study

was extracted from different resources and reviewed. In this chapter, the rest of the

steps required for conducting this study are going to be explained.

3.2 General Framework

The general framework shown in Figure 3.1 illustrates the main steps

required to be followed for carrying out the study. After the problem was stated and

the objectives were set at the beginning of the study, the rest of the steps that is

needed to be followed in order to acquire the results and findings were established

and organized in the form of flowchart. Components of the general framework are

described in the following section of this chapter.

24

Figure 3.1 General Framework

Problem Statement

Site Reconnaissance & Pilot

Study

Field Data Collection

Data Extraction

Data Analysis

Result and Discussion

Conclusion

Aim and Objective

Literature Review

Study Method Formulation

Defining Required Data

25

3.2.1 Site Selection

Bulatan Seksyen 15, Bandar Baru Bangi was selected as the location for the

case study after observation and discussion with the local authority which is Jabatan

Kerja Raya Daerah Hulu Langat, Selangor. Bulatan Seksyen 15 is a roundabout

connecting Tol Bangi, Persiaran Wawasan, Persiaran Pekeliling, and Persiaran

Kemajuan. Bandar Baru Bangi is a township situated in Hulu Langat region, in

southeastern Selangor. It is named after the small town of Bangi situated further

south. Figure 3.2 shows the roundabout for the study area, where three approaches of

the roundabout are signalised with semi-actuated traffic signal system which is from

Persiaran Wawasan, Persiaran Pekeliling, and Tol Bangi while approach from

Persiaran Kemajuan is unsignalised. Each approaches of the roundabout composed of

three lanes both ways with one lane situated for left turning. Each signal timing is

independent with each other, which means they are not synchronize. The area is

commercial and residential.

Figure 3.2 Study Area

26

3.2.2 Identification of the Required Data

Before starting any study, a set of parameters and required data should be

identified in order to carry out the analysis systematically without any missing

variables and re-doing the data collection. To avoid interruption in the analysis stage,

the following sets of parameters were defined.

3.2.2.1 Field Geometry

This includes all the existing and required on information about the layout of

the junction such as junction of approaches, number of lanes, lane widths, and

roundabout size. These data were collected by measurement achieved in field.

3.2.2.2 Traffic Data

The traffic data includes all the necessary information about the

characteristics of the traffic stream. They were classified into:

• Traffic volume: Number of vehicles crossing the stop line of each approach

in unit of time

• Type of vehicles: Traffic stream are not composed of identical vehicles, and

each type of vehicle has a different impact on the traffic characteristics.

Therefore, traffic volume was classified into different vehicle groups.

3.2.2.3 Traffic Signal Indication

This includes all the information about the traffic signal provided at the

junction such as cycle time, green time, extended green time, and clearance interval

for each phases.

27

3.2.3 Data Collection

In order to do an evaluation of the performance at the junction, traffic volume

and signal indication at the roundabout were obtained. The data was obtained with

the help from JKR Hulu Langat staff using manual counting technique. Two

observers were positioned at each approach where one observer counted the vehicles

going into the roundabout while the other observer counted the vehicles left turning

to next junction. The data was collected for two days which is on Tuesday and

Wednesday, from 6am until 8pm. Based on the collection of the two days data, only

the highest traffic flow was used to evaluate the current signalised roundabout

performance.

Figure 3.3 Manual traffic count at Bulatan Seksyen 15, Bandar Baru Bangi

28

3.2.4 Data Extraction

The recorded data was then extracted and summarized into the required

forms. Traffic data volume was converted into pcu/hour to obtain the total traffic

composition for each approach as the data was used as an input in calculation of

control delay.

Figure 3.4 Excel form

29

3.2.5 Data Analysis

The data was then analysed by using guideline in Arahan Teknik (Jalan)

13/87 based on the input data determined in the data collection. Input data is from

traffic volume that have been converted into pcu/hour for each approach based on the

highest peak time and signal indication during data collection. The equation of

control delay is written as below:

d =9

10[

𝑐(1−𝜆)2

2(1−𝜆x)+

𝑥2

2(𝑞

3600)(1−𝑥)

] sec…………………………………… Equation 5

Where

q = traffic volume, pcu/sec

S = saturation flow, pcu/sec

λ = effective green, g/c

c = cycle time

x = degree of saturation, q/λs

From the control delay obtained from the Equation 5, the level of service

from each approach was determined by referring to Table 3.1 which has been

discussed in Chapter 2.

Table 3.1 Level of Service


A < 5

B 5.1 to 15.0

C 15.1 to 25.0

D 25.1 to 40.0

E 40.1 to 60.0

F > 60.0

30

3.2.6 Result and Discussion

The final step of the operation analysis process was interpreting the results. If

the result does not meet the requirement according to ATJ 11/87 which stated the

minimum allowable level of service, the roundabout needs to be upgraded. SIDRA

INTERSECTION software was used to model the new traffic signal control for the

roundabout.

31

CHAPTER 4

RESULT AND ANALYSIS

4.1 Introduction

The aim of this study is to evaluate the road performance of a signalised

roundabout. In this chapter, detailed analysis of the evaluation process is presented.

The analysis process starts from traffic volume studies, signal indication, control

delay measurement, and level of service.

4.2 Traffic Volume

The site is a signalised roundabout which consists of four approaches namely

Persiaran Kemajuan, Persiaran Pekeliling, Persiaran Wawasan, and Tol Bangi. Each

approaches are composed by three lanes each direction with one lane situated for left

turning, with each lane is 3.5m wide. Persiaran Kemajuan, Persiaran Pekeliling, and

Tol Bangi approaches have a 2.5m wide built out median while Persiaran Wawasan

has a 4m wide built out median. Figure 4.1 shows the layout of the junction.

32

Figure 4.1 Junction layout

Manual counting technique was used for traffic volume studies of Bulatan

Seksyen 15, Bandar Baru Bangi. Table 4.1 to Table 4.8 shows the summary of traffic

volume for all eight directions of the junction respectively. The traffic volume count

was conducted for 14 hours which is from 6am until 8pm. Based on the data

collected, it was found that the traffic data collected on Wednesday has the highest

traffic flow compared to the traffic data collected on Tuesday. The total number of

observed vehicles on Wednesday was 61,690 vehicles. From the previous Chapter 3

in data collection, it was highlighted that the highest peak time volume between

morning peak and evening peak will be chosen to determine the current performance

of the signalised roundabout. Based on data extraction, it is found that the peak hour

in the morning is from 7am until 8am while the peak hour in the evening is from 5pm

until 6pm.

33

Table 4.1 Vehicle volume per 1 hour interval from Persiaran Kemajuan to Persiaran

Pekeliling

Time Motocar and Taxi

Small van and utility

(Light - 2 axle)

Lorry and Big

Van (Heavy - 2 axle)

Lorry with 3 axle or Trailer (Heavy

and exceed 2

axle)

Bus Motorcycle Total

0600-0700 72 14 7 4 17 73 187

0700-0800 335 66 3 3 4 139 550

0800-0900 49 29 10 1 4 63 156

0900-1000 143 73 22 17 14 102 371

1000-1100 126 58 8 4 2 43 241

1100-1200 177 36 16 1 3 51 284

1200-1300 207 68 19 4 4 76 378

1300-1400 202 32 15 2 3 57 311

1400-1500 213 40 12 1 3 60 329

1500-1600 193 97 22 7 4 83 406

1600-1700 304 137 15 2 3 153 614

1700-1800 418 160 20 3 3 227 831

1800-1900 323 59 15 1 31 289 718

1900-2000 317 142 37 19 12 254 781

Total 3079 1011 221 69 107 1670 6157

34


Roundabout



(Light - 2 axle)

Lorry and Big



and exceed 2

axle)


0600-0700 80 19 5 3 15 83 205

0700-0800 524 153 8 6 1 92 784

0800-0900 233 76 27 17 3 75 431

0900-1000 305 64 49 39 0 71 528

1000-1100 236 75 61 42 0 83 497

1100-1200 282 55 49 17 0 62 465

1200-1300 272 62 31 20 0 71 456

1300-1400 312 124 65 29 3 75 608

1400-1500 341 172 42 40 0 58 653

1500-1600 276 113 39 34 1 61 524

1600-1700 307 109 71 66 0 79 632

1700-1800 224 72 27 20 4 120 467

1800-1900 210 56 17 12 0 87 382

1900-2000 190 41 10 7 0 77 325

Total 3792 1191 501 352 27 1094 6957

35

Table 4.3 Vehicle volume per 1 hour interval from Persiaran Pekeliling to Persiaran

Wawasan



(Light - 2 axle)

Lorry and Big



and exceed 2

axle)


0600-0700 110 10 4 1 4 54 183

0700-0800 128 8 3 0 6 112 257

0800-0900 270 6 3 3 2 132 416

0900-1000 137 8 14 2 2 86 249

1000-1100 154 20 12 0 1 169 356

1100-1200 116 11 7 0 1 29 164

1200-1300 217 20 9 2 3 53 304

1300-1400 198 15 7 0 6 67 293

1400-1500 163 18 4 0 2 69 256

1500-1600 137 15 7 2 5 53 219

1600-1700 193 4 9 2 5 107 320

1700-1800 70 3 2 0 1 49 125

1800-1900 157 7 3 0 2 121 290

1900-2000 142 15 9 0 5 93 264

Total 2192 160 93 12 45 1194 3696

36


Roundabout



(Light - 2 axle)

Lorry and Big



and exceed 2

axle)


0600-0700 1121 37 8 2 24 178 1370

0700-0800 1515 77 11 1 6 685 2295

0800-0900 1272 73 17 8 17 475 1862

0900-1000 911 80 39 7 4 214 1255

1000-1100 731 96 40 9 2 176 1054

1100-1200 900 30 36 6 6 127 1105

1200-1300 1168 77 48 6 9 220 1528

1300-1400 1087 64 46 8 4 167 1376

1400-1500 978 57 23 5 17 152 1232

1500-1600 764 71 37 4 1 149 1026

1600-1700 970 94 34 2 3 164 1267

1700-1800 1250 13 19 6 34 237 1559

1800-1900 872 39 13 1 8 204 1137

1900-2000 884 61 6 3 5 194 1153

Total 14423 869 377 68 140 3342 19219

37

Table 4.5 Vehicle volume per 1 hour interval from Persiaran Wawasan to Tol Bangi



(Light - 2 axle)

Lorry and Big



and exceed 2

axle)


0600-0700 102 10 3 0 0 11 126

0700-0800 187 16 0 1 0 72 276

0800-0900 126 16 1 3 0 61 207

0900-1000 69 17 4 1 0 23 114

1000-1100 79 12 5 9 0 15 120

1100-1200 88 27 6 14 0 21 156

1200-1300 89 17 9 3 0 20 138

1300-1400 84 20 3 5 0 19 131

1400-1500 98 17 5 2 0 14 136

1500-1600 87 12 10 6 0 11 126

1600-1700 193 17 3 4 0 31 248

1700-1800 442 90 6 2 1 57 598

1800-1900 499 75 5 1 0 40 620

1900-2000 170 12 2 2 0 22 208

Total 2313 358 62 53 1 417 3204

38

Table 4.6 Vehicle volume per 1 hour interval from Persiaran Wawasan to

Roundabout



(Light - 2 axle)

Lorry and Big



and exceed 2

axle)


0600-0700 167 20 5 0 6 43 241

0700-0800 573 33 0 0 5 93 704

0800-0900 305 19 10 1 2 44 381

0900-1000 196 13 9 3 3 35 259

1000-1100 198 21 19 1 3 52 294

1100-1200 256 27 15 0 1 59 358

1200-1300 360 30 16 0 6 71 483

1300-1400 329 23 15 1 3 68 439

1400-1500 282 51 10 1 3 60 407

1500-1600 298 29 8 1 2 91 429

1600-1700 347 38 6 0 3 107 501

1700-1800 610 25 13 1 6 103 758

1800-1900 378 14 6 1 6 136 541

1900-2000 197 13 3 0 4 48 265

Total 4496 356 135 10 53 1010 6060

39

Table 4.7 Vehicle volume per 1 hour interval from Tol Bangi to Persiaran Kemajuan



(Light - 2 axle)

Lorry and Big



and exceed 2

axle)


0600-0700 235 18 24 5 0 142 424

0700-0800 673 101 6 4 1 186 971

0800-0900 846 40 14 10 3 304 1217

0900-1000 431 48 13 6 1 116 615

1000-1100 172 9 22 19 1 29 252

1100-1200 146 21 10 5 0 35 217

1200-1300 179 56 35 18 0 34 322

1300-1400 193 74 25 19 0 8 319

1400-1500 185 55 14 8 1 27 290

1500-1600 161 40 9 9 2 16 237

1600-1700 191 30 23 25 1 26 296

1700-1800 180 55 26 13 0 47 321

1800-1900 202 5 9 10 0 120 346

1900-2000 85 26 4 3 0 31 149

Total 3879 578 234 154 10 1121 5976

40

Table 4.8 Vehicle volume per 1 hour interval from Tol Bangi to Roundabout



(Light - 2 axle)

Lorry and Big



and exceed 2

axle)


0600-0700 205 48 11 2 4 27 297

0700-0800 795 194 7 13 4 173 1186

0800-0900 771 186 22 12 2 275 1268

0900-1000 482 120 28 11 2 92 735

1000-1100 296 6 22 10 3 85 422

1100-1200 571 41 49 14 4 62 741

1200-1300 430 78 19 14 3 67 611

1300-1400 425 54 27 9 2 54 571

1400-1500 641 47 18 2 0 123 831

1500-1600 618 97 24 17 0 66 822

1600-1700 565 121 22 14 4 70 796

1700-1800 563 79 18 7 1 133 801

1800-1900 465 51 6 2 2 175 701

1900-2000 370 120 15 2 2 130 639

Total 7197 1242 288 129 33 1532 10421

41

4.3 Traffic Composition

Each type of vehicle has a different impact on traffic characteristic of a traffic

stream. Therefore, traffic volume observed during the study time was classified into

six main categories of vehicles. Figure 4.2 illustrate the distribution of the traffic

volume based on the vehicle types at Bulatan Seksyen 15, Bandar Baru Bangi. Figure

4.3 to Figure 4.6 illustrate the traffic composition at Bulatan Seksyen 15 according to

each approaches into the roundabout. From the traffic composition pie chart, it can

be concluded that the majority of the traffic volume is composed of passenger cars

with 67% (41,371 vehicles), and the second highest is motorcycles with 19% (11,380

vehicles).

Figure 4.2 Traffic composition at Bulatan Seksyen 15, Bandar Baru Bangi

67%9%

3%

1%

1%19%

TRAFFIC COMPOSITION AT BULATAN SEKSYEN 15, BANDAR BARU BANGI

Motocar and Taxi

Small van and utility (Light - 2axle)

Lorry and Big Van (Heavy - 2axle)

Lorry with 3 axle or Trailer(Heavy and exceed 2 axle)

Bus

Motorcycle

42

Figure 4.3 Traffic composition from Persiaran Kemajuan to the roundabout

Figure 4.4 Traffic composition from Persiaran Pekeliling to the roundabout

55%

17%

7%

5%

0%

16%

TRAFFIC COMPOSITION FROM PERSIARAN KEMAJUAN

Motocar and Taxi




Bus

Motorcycle

75%

5%2%

0%1%

17%

TRAFFIC COMPOSITION FROM PERSIARAN PEKELILING

Motocar and Taxi




Bus

Motorcycle

43

Figure 4.5 Traffic composition from Persiaran Wawasan to the roundabout

Figure 4.6 Traffic composition from Tol Bangi to the roundabout

74%

6%2%

0%

1%

17%

TRAFFIC COMPOSITION FROM PERSIARAN WAWASAN

Motocar and Taxi




Bus

Motorcycle

69%

12%

3%

1%

0%

15%

TRAFFIC COMPOSITION FROM TOL BANGI

Motocar and Taxi




Bus

Motorcycle

44

After the data was extracted according to each approaches, it was converted

into pcu/hour to obtain total vehicle for that approach. Table 4.9 shows the summary

of the traffic composition according to peak time. From Table 4.9, it is found that the

morning peak time has the highest volume compared to evening peak time. Based on

Figure 4.7 and 4.8, Persiaran Pekeliling was recorded with the highest number of

vehicles during both morning and evening peak hour, followed by Tol Bangi.

Table 4.9 Summary of traffic composition

Direction Veh/hour pcu/hour

AM PM AM PM

Persiaran Kemajuan

784 467 852 491

Persiaran Pekeliling

2295 1559 1911 1474

Persiaran Wawasan

704 758 673 726

Tol Bangi 1186 801 1242 795

Figure 4.7 Traffic volume at morning peak hour

0

500

1000

1500

2000

2500

PersiaranKemajuan

Persiaran Pekeliling Persiaran Wawasan Tol Bangi

Traffic Volume at AM peak hour

45

Figure 4.8 Traffic volume at evening peak hour

4.4 Delay and Level of Service

Control delay was calculated based on the formula mentioned in Equation 5

in Chapter 3. Table 4.10 and Table 4.11 summarise the calculation for control delay

for the signalised approaches which is from Persiaran Pekeliling, Persiaran

Wawasan, and Tol Bangi. Table 4.12 to Table 4.14 shows the actuated signal system

timing for current signal indication where F1 indicates the phase for approaching

lane entering the roundabout and F2 indicates the phase of the circulating traffic

inside the roundabout. The results from the calculation of the level of service has

shown that the LOS for the traffic stream is in category E and D (Figure 4.9). This

level of service can be categorised as unstable flow where the waiting time exceeds

the cycle time before proceeding the stop line.

0

200

400

600

800

1000

1200

1400

1600

1800

PersiaranKemajuan

Persiaran Pekeliling Persiaran Wawasan Tol Bangi

Traffic Volume at PM peak hour

46

Table 4.10 Summary of current delay for AM peak hour

Approach Persiaran Pekeliling

Persiaran Wawasan

Tol Bangi

Traffic Volume (veh/h)

2295 704 1186

Traffic Flow, q (pcu/h)

1910.8 672.69 1242.09

Cycle time, c 150 123 125

Green time, g 60 70 65

Effective green, ge 40 46.667 43.333

λ 0.267 0.379 0.347

s 3675 3675 3675

x 1.950 0.482 0.975

delay, d 76 26 36

LOS E D D

Table 4.11 Summary of current delay for PM peak hour

Approach Persiaran Pekeliling

Persiaran Wawasan

Tol Bangi

Traffic Volume (veh/h)

1559 758 801

Traffic Flow, q (pcu/h)

1474.21 726.24 794.64

Cycle time, c 150 123 125

Green time, g 60 70 65

Effective green, ge 40.000 46.667 43.333

λ 0.267 0.379 0.347

s 3675 3675 3675

x 1.504 0.521 0.624

delay, d 61 27 31

LOS E D D

Table 4.12 Actuated signal timing for Persiaran Pekeliling

GAP MIN MAX FLASH AMBER RED

F1 3.5 10 60 5 3 2

F2 5 10 70 5 3 2

Table 4.13 Actuated signal timing for Persiaran Wawasan


F1 5 10 70 4 2 3

F2 3.5 10 35 4 2 3

47

Table 4.14 Actuated signal timing for Tol Bangi


F1 5 10 65 5 3 2

F2 4 10 40 5 3 2

Figure 4.9 Current level of service for signalised approaches

In the previous Chapter 2, the minimum required level of service for the

signalised junction according to ATJ 11/87 is category D. If such level of service

cannot be sustained throughout the design life of the projected forecast the designer

has to propose a mitigation measure. Current level of service in the study area does

not fulfill the minimum requirement since the level of service at Persiaran Pekeliling

approach has a LOS of E. Therefore, we need to propose a mitigation measure for the

signalised roundabout.

According to Jabatan Kerja Raya Hulu Langat, the local authority in charge

for the road in the study area, several changes have been made on the traffic signal

D (D)

D (D)

E (E)

AM (PM)

48

timing in order to gain a smooth traffic stream for the approaching lanes. However,

they could not find a traffic signal timing that could maintain the smooth traffic

stream for a long period of time because congestion keep happening after several

months the changes is made. Thus, a different method need to be propose other than

redesigning the signal indication for the roundabout.

By using SIDRA INTERSECTION software, two methods has been proposed

which are installing ramp metering and changing the signalised approaches to

unsignalised approaches. Based on the proposed method, the level of service for

some approaches are slightly improved after implying the changes. Figure 4.10 and

Figure 4.11 shows the level of service for the roundabout if the signal control system

is removed, while Figure 4.12 shows the level of service for the roundabout if ramp

meter replaced the existing vehicle actuated signal system.

Figure 4.10 LOS for unsignalised approaches for AM peak hour by using

SIDRA INTERSECTION

49

Figure 4.11 LOS for unsignalised approaches for PM peak hour by using

SIDRA INTERSECTION

Based on Figure 4.10, Persiaran Pekeliling and Tol Bangi has shown a good

performance with LOS A while Persiaran Wawasan has shown a poor performance

with LOS F. In Figure 4.11, all approaches has shown a good performance with LOS

A. This result indicates that turning the signalised roundabout into unsignalised

roundabout could improve the level of service for the roundabout. However, the level

of service for Persiaran Wawasan approach for evening peak hour has poor

performance with LOS F. Thus, an improvement need to be done in order to improve

the level of service for the respective approach.

50

Figure 4.12 LOS for ramp metering by using SIDRA INTERSECTION

Based on Figure 4.12, Persiaran Pekeliling is the metered approach while

Persiaran Wawasan is the controlling approach. At controlling approach, detector

loops were installed to detect incoming vehicles while at the metered approach, a

traffic signal is installed to provide signal indication. The sensor at the controlling

approach will have a setback distance from the stop line which will detect the

presence of vehicles after several vehicles have started to queue at the approach.

When the sensor is triggered, it will send information to the traffic signal at the

metered approach to indicate a red light. This will allow the vehicles at the

controlling approach to enter the roundabout with less interruption from the metered

approach.

After a minimum or maximum red time is reached, the traffic signal will turn

green again. In a situation where the queue at the controlling approach is short and

51

does not trigger the sensor, the traffic signal at the metered approach will always be

green. However, another detector loops will be installed at the metered approach

with certain setback distance. After this sensor is triggered, the traffic signal will turn

green while neglecting the queue at the controlling approach. This is to avoid a very

long queue at the metered approach which may cause a serious traffic congestion.

Several other options have been tested and this arrangement provides the best

level of service among others options. Persiaran Kemajuan and Tol Bangi

approaches have shown a good performance with LOS A, Persiaran Wawasan

approach shows a LOS C and Persiaran Pekeliling approach shows a poor

performance with LOS F. Tol Bangi and Persiaran Wawasan has shown an improved

LOS from the signalised signal system from LOS D to LOS A and C. However,

Persiaran Pekeliling has dropped in performance from LOS E to LOS F.

4.5 Summary

Based on the results presented in this chapter, the following conclusion can

be made:

i. Traffic volume at the junction for 14 hours observation was 61,690

vehicles. It was found that the highest traffic composition is passenger car

and the second highest is motorcycle. Based on all four approaches,

Persiaran Pekeliling has the highest volume of vehicles with 22,915

vehicles along the period of data collection.

ii. From the data collection, control delay was determined by using

guidelines in ATJ 11/87. Current level of service for the junction are LOS

D and LOS E which does not comply with the minimum requirement for

the junction performance which is LOS D. Therefore, converting the

signalised approaches into unsignalised approaches or ramp metering

have been proposed as the mitigation measures.

52

CHAPTER 5

CONCLUSION AND RECOMMENDATIONS

5.1 Introduction

This research presents the evaluation of road performance at signalised

roundabout in Bulatan Seksyen 15, Bandar Baru Bangi. From the study, it was found

that the level of service for the traffic stream is on category D and E. The problem

can be seen in the Persiaran Pekeliling approach where it indicates LOS E. This is

due to high traffic volume but having a short green period. Therefore, in can be

concluded that the approaches experience unstable flow. A mitigation measure need

to be done to solve the congestion problem. Thus, converting the signalised

approaches to unsignalised approaches or ramp metering were suggested as the

method to mitigate the problem.

5.2 Findings

5.2.1 Objective 1: To determine the traffic characteristic in term of volume

and composition

The volume of vehicles at signalised roundabout was determined for two

weekdays from 6am to 10pm and the highest volume between the days was used for

data analysis. Manual counting technique was used to obtain the traffic volume. It

was found that the highest traffic composition is passenger car, followed by

motorcycle. Based on the four approaches at the roundabout, Persiaran Pekeliling

approach shows the highest number of vehicles with 22,915 vehicles. The total

number of vehicles at the roundabout is 61,690 vehicles for 14 hours duration.

53

5.2.2 Objective 2: To determine the control delay at signalised roundabout

Control delay was determined in order to identify the performance of the

signalised roundabout. Control delay was determined by using Equation 1 as

mentioned in Chapter 3. It was found that the average delay time for the roundabout

is between 20 and 80 seconds (76 sec, 26 sec, 36 sec, 61 sec, 27 sec, and 31 sec).

5.2.3 Objective 3: To determine the level of service (LOS) of each approaches

Level of service was obtained by calculating the control delay by using

guidelines in Arahan Teknik Jalan 11/87. By referring the table for level of service in

the guideline, it was found that the level of service for the traffic stream is between

category D and E. The problem can be seen in Persiaran Pekeliling approach where it

recorded LOS E.

5.3 Recommendation for Future Works

The mitigation measures of this study was modeled by using SIDRA

INTERSECTION and was only used to determine the level of service of the

signalised roundabout if it is converted into unsignalised system. Therefore, to obtain

other alternative method to mitigate the congestion problem, it is recommended that:

1) Collect the traffic volume of vehicles entering each approaches to

determine the vehicles journey and proportion of vehicles entering each

approaches. This data can be used to model the roundabout using VISSIM

software to get a detailed level of service considering the trip journey of

each vehicles on the roundabout.

2) Redesign the traffic signal timing to obtain a satisfactory control delay of

each signalised approaches by using available guidelines.

54

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Appendix A Data Collection Table

Negeri : Seksyen :

Daerah : Jalan :

Tarikh : No. Laluan :

Hari : KM :

0600-0700

0700-0800

0800-0900

0900-1000

1000-1100

1100-1200

1200-1300

1300-1400

1400-1500

1500-1600

1600-1700

1700-1800

1800-1900

1900-2000

2000-2100

2100-2200

Jumlah

JumlahMasaMotokar

dan Teksi

Van kecil &

Utiliti

(Ringan - 2

gandar)

Lori & Van

Besar

(Berat - 2

gandar)

Lori

dengan 3

gandar

atau Treler

(Berat -

Bas Motosikal

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