DEPARTMENT OF CE

TRAFFIC VOLUME STUDY

Course Title : Transportation Engineering Sessional II Course No : CE 452

Course Teacher : Minhajul Islam Khan

Nuzhat Azra

GROUP 2

Group members Student ID

ZOBAER SALEHEEN 11.01.03.100

IMRAN UDDIN MAHMUD 11.01.03.106

SIAM MOHAMMAD AZMIH 11.01.03.107

MD. KAMRUZZAMAN MAHFUZ 11.01.03.109

ZAKIRUL ISLAM 11.01.03.108

MAKSUD AL SHABIB 11.01.03.110

KAZI GOLAM MOSTOFA 11.01.03.116

MD. NAZMUL ISLAM 10.01.03.103

ABDULLAH IBNE FARUK 10.02.03.105

OUTLINE

1. Introduction

2. Objectives

3. Scope of The Traffic Volume Study

4. Key words for volume study

5. Methodology

6. Data Presentation

7. Discussion

8. Limitation of the study

9. Recommendation

INTRODUCTION

• Traffic volume study is the procedure to determine mainly the volume of traffic moving on roads on a particular section during a particular time.

• Volumes of a day or an hour can vary greatly, depending on the different day of the week or different time period of a day.

• Traffic Volume survey is a systematic way of collecting data which is used for various traffic engineering purposes.

OBJECTIVE

Counting is the most fundamental measurement in traffic engineering: vehicles, passenger etc.

Counting technique to produce estimates of volume, rate flow, demand and capacity.

The purposes of carrying out traffic volume count are designing, improving traffic system, planning, management etc.

Traffic volume study is used in plan.

GENERAL OBJECTIVES

• Design Purposes

Structural and geometric design of pavements, bridge, highway facilities, side-walks, pedestrian crossing , minimum turning path, channelization, flaring, and traffic control devices etc.

• Improvement Purposes

To improve the roadway operating condition, examine the existing service condition, check the need of traffic control devices etc.

• Planning Purposes

Accurate information on the amount of traffic on the roads for the planning of both road maintenance and improvement policies.

• Dynamic Traffic Management Purposes

Up to date and continuous flow/congestion information is essential for optimizing - Traffic signal design and thereby improving junction performance and Network productivity by providing information to the road user.

SPECIFIC OBJECTIVES

• To determine vehicle composition during survey period

• To determine service flow rate in PCU unit

• To determine Directional Distribution of traffic

• To estimate average daily traffic based on expansion factor

• To draw partial flow fluctuation curve

SCOPE OF THE TRAFFIC VOLUME STUDY

SOME KEY WORDS FOR VOLUME STUDY

• Volume: Volume on a road is the number of vehicles passing the measurement point during a specified time interval.

• ADT: Average daily traffic or ADT is the average number of vehicles (two-way) passing a specific point in a 24-hour period, normally measured throughout a year.

• AADT: Annual average daily traffic or AADT is the total volume of vehicle traffic of a highway or road for a year divided by 365 days.

• Service flow rate: The maximum hourly rate of a roadway section during a given period under prevailing roadway condition.

• Rate of flow: The equivalent hourly rate at which vehicles pass over a given point or section of a lane or roadway during a time interval less than 1hr, usually 15 min.

• Daily Traffic Expansion Factor:

HEF =

DEF =

MEF =

METHODOLOGY

Traffic volume study

Direct Method

Manual

Automatic

Indirect method

Video recording

Pass card

MANUAL COUNTING METHOD

Mainly 3 steps--

1. Prepare.

Determine the type of equipment to use, the field procedures to follow, and the number of observers required.

Label and organize tally sheets. Each sheet should include information about the location, time and date of observation, and weather conditions.

2. Select observer location .

Observers (data collectors) should be positioned where they have a clear view of traffic and are safely away from the edge of the roadway.

3. Record observations on site.

EQUIPMENTS USED FOR MANUAL COUNTING METHODS

Tally Sheets

Recording data onto tally sheets is the simplest means of conducting manual counts. The data can be recorded with a tick mark on a pre-prepared field form. A watch or stopwatch is necessary to measure the desired count interval

Mechanical Counting Boards

Mechanical count boards consist of counters mounted on a board that record each direction of travel. Common counts include pedestrian, bicycle, vehicle classification, and traffic volume counts.

Electronic Counting Boards:

Electronic counting boards are battery-operated, hand-held devices used in collecting traffic count data. They are similar to mechanical counting boards, but with some important differences.

AUTOMATIC COUNTING METHOD

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

• There are two techniques of automatic counting Contact system based:-

It is based on pneumatic, mechanical, magnetic or piezo -electric method. Contactless system based:-

It is based on electrical/optical, ultrasound/infrared radar, micro wave,

CCTV/video image processing method.

EQUIPMENTS USED FOR AUTOMATIC COUNTING METHODS

Bending plate

A weight pad attached to a metal plate embedded in the road to measure axel weight and speed. It is an expensive device and requires alteration to the road bed.

Pneumatic road tube

Pneumatic road tube sensors send a burst of air pressure along a rubber tube when a vehicle's tires pass over the tube.

Piezo-electric sensor

A device that is placed in a groove cut into the roadbed of the lane(s) being counted. This electronic counter can be used to measure weight and speed.

Piezo-electric sensor

Inductive loops

Inductive loop detector consists of an oscillator, and a cable, which allows signals to pass from the loop to the traffic counting device. The counting device is activated by the change in the magnetic field when a vehicle passes over the loop.

Some others way Count Vehicles Using Hand-

Held Electronic Counter Boards

Vehicles numbers are recorder using ultrasound, light beam or other infrared technology.

INDIRECT METHOD

Video recording :

Video cameras are mounted to record the traffic condition on road. Traffic volumes can be counted by viewing videotapes recorded with a camera at a collection site.

Pass card

In this system every traffic have certain card. When passing a certain area the driver just use the card in a booth. Thus the traffic volume can be measured

DATA COLLECTION

SURVEY LOCATION

Survey Date 15th January 2014

Survey route Russell Square to Panthapath (near Envoy tower and Concord Regency)

Weather condition Nice sunny day with 24°C and 62% humidity

Method Direct count with manual method

Equipment Hand Counter , Pencil , Clip Board , Data Sheets

No. of enumerator 9

DATA ANALYSIS

• Vehicle Composition in Traffic Stream

• Service Flow Rate in PCU/ PCE unit

• ADT based on Expansion Factors

• Directional distribution

• Flow Fluctuation Curves

TRAFFIC VOLUME COUNTING DATA

Time 10.30-11.00

AM

Day Thursday

Date 22.11.2014

Direction of Flow Panthapath to Russell Square(East to West)

Surveyor Group Group 2

Vehicle Classification Observation in 30 min

Bus 5

CNG 90

Car 300

Jeep,Microbus,Ambulance 79

Motorcycle 88

Non-Motorized Vehicles ( NMV)

329

Utility 25

Truck 0

Total 916

VEHICLE COMPOSITION OF TRAFFIC STREAM

36%

1%10%

33%

3%

9%

10%

Vehicle Composition

Non-Motorized Vehicles ( NMV)( 35.92% )

Bus (.55 % )

CNG( 9.83% )

Truck( 0% )

Car( 32.75% )

Utility( 2.72% )

Jeep,Microbus,Ambulance( 8.62% )

Motorcycle( 9.61% )

SERVICE FLOW RATEVehicles

ClassificationNumber PCU Factor Converted

NumberBus 5 3 15CNG 90 .5 45

Car 300 1 300Jeep, Microbus,

Ambulance79 1.5 118.5

Motorcycle 88 .25 22NMV 329 .5 164.5

Utility 25 1.5 37.5Truck 0 3 0total 916   703

Level of Service ( LOS)

Service flow rate (PCU/hr.)

A 600

B 700

C 900

D 1200

E 1400

F >1400

From table A we can see, Traffic flow for time Duration (10.30 AM to 11.00 AM) is 703 PCU and Service Flow Rate for time Duration (10.30 AM to 11.00 AM) is 1406 PCU. Comparing our traffic flow value (PCU/hr.) with the table B we can say that the Level of Service of our road during 10:30 AM to 11:00 PM is Level ‘F’ which means forced or breakdown flow state.

Table B: Level of Service vs. Service Flow RateTable A: Conversion of Flow Rate in PCU

ADT AND AADT CALCULATION

• Estimating 24-hr volume using the Hourly Expansion Factors (HEF) for East to West (Panthapath to Russell Square) traffic flow direction we get the ADT is 26045 PCU/day.

• Estimating 24-hr volume using the Hourly Expansion Factors (HEF) for West to East (Russell Square to Panthapath) traffic flow direction we get the ADT is 31494 PCU/day .

• From the both direction avg. ADT , we get the Annual Average Daily Traffic, (AADT) is 100944 PCU/day.

DIRECTIONAL DISTRIBUTION

• The Directional distribution is defined as the percentage of heavier volume over the total highway volume.

• This directional distribution is relevant only when designing or analyzing highways with two or more lanes in one direction.Direction Time PCU/hr. Average

PCU/hr.Directional

Distribution DD% of total

traffic volume

From Panthapath To Russell Square

9.00 am – 9.30 am 1345    

1432

   

45%

31.5

10.30 am – 11.00 am

1405 32.7

11.00 am – 11.30 am

1546 36

From Russell Square to

Panthapath

9.00 am – 9.30 am 1822    

1732

    55%

35

10.30 am – 11.00 am

1690 32.6

11.00 am – 11.30 am

1682 32.4

PIE CHART OF DIRECTIONAL DISTRIBUTION OF FLOW

45%

55%

Directional Distribution of Traffic Flow

From Panthapath to Russel SquareFrom Russel Square to Panthapath

According to directional

distribution most of the vehicle

travel towards Panthapath, as

this road leads to the city center

and the survey was made in the

work going phase of the day, so

directional distribution was

justified.

FLOW FLUCTUATION CURVE

• Flow Fluctuation Curve: Graph of %ADT versus Time usually for a 24 hour period.

• 24 hour flow fluctuation curve gives

• Peak Hour Factor (PHF)

• Design Hourly Volume (DHV) = PHF x ADT

FLOW FLUCTUATION CURVE

1000

1100

1200

1300

1400

1500

1600

1700

1800

1900

1583.51548

1614

[Y VALUE]

16901682

13451405

1546

Flow Fluctuation Curve

From Panthapath to Russell SquareFrom Russell Square to PanthapathAverage

Observation time

P C

U/h

r

9.00-9.30 AM 10.30-11.00 AM 11.00-11.30 AM

DISCUSSION ON VEHICLE VOLUME

Vehicle composition shows that 36% of the total vehicle is NMV (Non-motorized Vehicle). Due to the development of the nearby land (Hospital, Food Court etc.) and increased in residential building the use of NMV for short distance has increased. The second most vehicle composition was Private car (33% of total vehicle composition). People from residential buildings were using private car for their journey to work place or any other destination which has increased the number of private car use.

DISCUSSION ON DIRECTIONAL DISTRIBUTION

55% of traffic flow was towards Panthapath which indicates tidal flow towards west-north. It was morning rush hour. And there are also some residential area in morning they rush to commercial area like Motijheel , Firmgate through this path. Since Panthapath has linked with the city center, so the rush towards Panthapath is high.

DISCUSSION ON FLOW FLUCTUATION

To draw flow fluctuation curve, it was assumed that volume for three continuous hours were counted, although all vehicles were counted within one hour. Flow rates were calculated from that short count data and plotted. The graphs we obtain do not signify anything because we only take data for three hour. If we take 24-hr reading and then plot in the graph we may develop a relation between the previous data and the data we obtained.

LIMITATIONS OF THE STUDY

• This volume study was practiced by un-skilled enumerators, which may lead to some error in data collection process.

• Direct Manual method being less accurate.

• More representative results of service flow rate would be obtained if 24 hours volume is counted and the flow-fluctuation curve would show two distinct peaks around morning and evening rush hours.

• Expansion factors used for the calculation of ADT were developed for a rural primary road.

• Proper enforcement of traffic regulation is not obtained.

• Data were collected for short-term (20 minute), which was not representative to the flow characteristics of the road. If 3days continuous data were collected, that would me much more representative than this short count of traffic volume.

RECOMMENDATIONS

• This road mainly served the purpose of collector road. Collector roads should be designed for a level of service C or better. However, level of service D is acceptable, where unusually high traffic volumes exist. But as it found from the traffic volume survey that the level of service was “F”, even during off-peak hour. This handicaps the serviceability of the road.

• Driver’s selection of speed and reduced ability to pass is reduced. The volume count must contain more than one cycle to get more authentic value

• More public transport facility should be provided to support the need of inhabitants living the residential area near the road.

• NMT should be prohibited in this road which will help to increase the Level of Service and Travel Speed.