Welcome to the Presentationon

Traffic Volume Study

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DEPARTMENT OF CIVIL ENGINEERINGAHSANULLAH UNIVERSITY OF SCIENCE & TECHNOLOGY

COURSE TITTLE : CE 452

COURSE NAME : Transportation Engineering Sessional -2

Course Teacher : Mr. Minhajul Islam Khan & Ms. Nuzhat Azra

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Presented by group 1

Amit Chandra Barman Jyotiram Mallick Shibu

Mohammad SayemMuktarul Kabir

Rafid NewazRifat Ahmed

Sourav TalukderTasneef Ahmed

11.01.03.12511.01.03.10411.01.03.10211.01.03.12311.01.03.12011.01.03.07111.01.03.12411.01.03.098

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Contents• Introduction• General Objectives of Traffic Volume Study• Study Site• Methodology• Survey procedure• Data Collection• Analysis of collected data• Conclusion• Recommendations• Limitations of the Study

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Traffic Survey

Planning And Designing Traffic Facilities

Determining The Need For Traffic Control Devices

Studying The Effectiveness Of Introduced Schemes;

Diagnosing Given Situations And Finding Appropriate solutions;

Forecasting The Effects Of Projected Strategies;

Calibrating And Validating Traffic Models Etc.

Traffic Surveys Are Required To Transportation Engineers For :

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Introduction

Traffic volume studies are conducted to determine the volume of traffic moving on the roads and classifications of roadway vehicles at 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 the determination of the number, movement and classifications of roadway vehicles at a given location.

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Specific Objectives

To determine vehicle composition duringsurvey 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

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General Objectives

A. Design Purposes

B. Improvement Purposes

A. Planning Purposes

C. Dynamic Traffic Management Purposes

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A . Design Purposes

Structural and geometric design of pavements, bridge,

and other highway facilities.

Intersection design including minimum turning path,

channelization, flaring, and traffic control devices.

Pedestrian volume study is useful for designing side-walks, pedestrian

crossing etc.

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• To allocate limited maintenance budget rationally, it is important to know the traffic volume carried by a particular roadway section in order to decide the importance of the road and fixing its relative priority.

• In order to improve the roadway operating condition, it is important to know the traffic volume –

• To examine the existing operating/service condition of a roadway section.

• To check the need (warrant) traffic control devices.

• To determine the type of improvement measure need to be taken.

• To measure the effectiveness of a traffic control measure.

B. Improvement Purposes

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Planning Purposes

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

Traffic volume network analysis helps in deciding/planning if there is need for Improvement and Expansion in terms of construction missing links, by-pass, alternative road etc.

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.

C. Planning Purposes & D. Dynamic Traffic Management Purposes

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Estimation of highway usage andmeasurement of current demand of a facility.

Estimation of trend.

Economic feasibility evaluation.

Computation of accident rates.

Other Purposes

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Scopes of Volume Study

SCOPES

Design

Planning

Improvement

Dynamic Traffic

Management

Estimating Highway

Use

Computing Accident

Rates

Traffic Stream

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Keywords Related To Volume Study

Volume/flow

Rate of flow

Average Daily Traffic (ADT )

Average Annual Daily Traffic (AADT)

Design Hourly Volume

Service flow rate

Directional Distribution

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Methodology

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Main Methods of Counting

• 1. Direct Method

• 2. Indirect MethodManual Counting

Method

• 1. Contact System

• 2. Contact-less SystemAutomatic

Counting Method

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Manual Count Recording Method(Filled Data Sheet and Summary Sheets)

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Figure: Example Manual Intersection

Volume Count Tally Sheet

Tally Sheets

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Car

Bus

Motorbike

CNG

Microbus/

Pajero

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Mechanical Counting Boards

Mechanical count boards consist of counters mounted on a board that record

each direction of travel.

Figure : Manual Counting Board20

Electronic Counting Boards

Figure : Electronic Counting Boards 21

Electronic counting boards are lighter, more compact, and easier to handle. This

is battery-operated, hand-held devices that are light, compact, and easy to handle

compared to tally sheets and mechanical boards

Steps to a manual traffic volume count

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

2. Select observer location(s) :

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.22

Automatic Counting Method

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Automatic Counting Methods

An automatic survey involves placing a tube or loop across a road

which is connected to a box containing the means for storing the

information.

In this method, vehicles are counted automatically without any human

involvement.

There are two techniques of automatic counting:

a) Contact system based on pneumatic, mechanical, magnetic or

piezo-electric method

b) Contactless system based on electrical/optical, ultrasound/infrared

radar, micro wave, CCTV/video image processing method etc.24

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.

Figure : Bending Plate 25

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.

Figure : Pneumatic Road Tube 26

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.

Figure : Piezo-electric Sensor27

Selected Method

Manual Method using hand tally and manual counters

Reasons

• Simple and Direct

• Classified vehicle count can be obtained

• Data can be used immediately after

collection

• No special equipment required

• Not costly• Easy to collect data

Figure : Hand Tally Counter28

Data Collection

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Survey Location

Study Location:Panthapath Road Segment between Russell Square and

Green road-Panthapath Intersection30

Information about Data Collection

Survey Date : 16th January, 2014

Survey route : Pathapath to Russel Square

Method :Manual Method using hand tally and

manual counters

Equipment : Hand Counter , Pencil , Clip Board , Data

Sheets

No. of enumerator : 8 persons

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Equipment Needed

Hand Counter

Supply of blank field data sheets

Pencils , erasers and pencil sharpner

Clip boards.

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RECONNAISSANCE SURVEYS

Reconnaissance survey and route

alignment survey was carried out to acquire

generalized idea about the survey area.

This survey ensures the physical

properties of location which cannot be

authenticated by Google Earth Maps.

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RECONNAISSANCE SURVEYS

Two private hospital, Square Hospital and Shomorita Hospital, is situated alongside

the road . So that traffic attraction is huge in this area.

No foot over bridge in this road .

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Geometric Layout of Intersection

Russel Square Intersection (Units in meter)

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Survey Procedure

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Data Analysis

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Vehicle Composition in Traffic

Stream

Service Flow Rate in PCU/ PCE unit

ADT based on Expansion Factors

Directional distribution

Flow Fluctuation Curves

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Traffic Volume Count DataVehicle Classification Observation in 30 min

Bus 8

CNG 76

Car 329Jeep, Microbus,

Ambulance 78

Motorcycle 89

NMV 245

Utility 20

Truck 0

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Vehicle Composition of Traffic

Stream

1%

9%

39%

9%

11%

29%

2% 0%

Vehicle Composition

Bus

CNG

Car

Jeep

Motorcycle

NMV

Utility

Truck

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Service Flow Rate

Flow Rate

The equivalent hourly rate at which vehicles pass over a given point or

section of a lane or roadway during a given time interval less than 1 hour

usually 15 minutes

Service Flow Rate

It is the equivalent hourly rate at which vehicle pass over a given point or

section of a lane or roadway during a given time interval less than 1 hr,

usually 15 min while maintaining a designated level of service.

Importance of Flow Rate

A short duration count (for e.g. 15 minutes count) can be converted into an

equivalent hourly rate

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Service Flow Rate SERVICE FLOW RATE IN (PCU)

VEHICLE PCU FACTOR FLOW TOTALVEH. IN 30

MINFLOW pcu IN 30

MINSERVICE

FLOW RATEPCU IN 1

HOURBUS 3 8 24 48

CNG 0.5 76 38 76

CAR 1 329 329 658JEEP,

MICROBUS,AMBULANCE

1.5 78 117 234

MOTORCYCLE(MC) 0.25 89 22.25 44.5

NMV 0.5 245 122.5 245

UTILITY 1.5 20 20 40

TOTAL 1345.5

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Service Flow Rate

Service Flow Rate (09:00-09:30AM) 1346 PCU/hr

From calculation it is found that the service flow rate of this corridor at 09:00am to

09:30 am was 1346 PCU/hr. Again, level of service of a road can be determined

from service flow rate. Level of service of a road can be classified according to

service flow rate as below

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LEVEL OF SERVICE VS SERVICE FLOW RATE

According to this table the level of service of Panthapath road was, “E” at 09:00 am-

09:30 am in Thursday.

LOS Service Flow Rate (PCU/hr)A 600B 700C 900D 1200E 1400F >1400

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Directional Distribution (DD)

Directional Distribution

The directional Distribution is defined as the percentage of heavier

volume over the total highway volume.

Importance of Directional Distribution

• Accounts for the directional distribution of traffic

• Used to convert average daily traffic to directional peak hour traffic

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Directional Distribution

Direction Time PCU/hr AveragePCU/hr

DirectionalDistribution

PanthapathTo

Russell Square

9:00 - 9:30 am 13461433 45%

10:30 – 11:00 1405

11:00-11:30 am 1546

Russell SquareTo

Panthapath

9:00 - 9:30 am 18221725 55%

10:30 – 11:00 1672

11.00 – 11.30 1682

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Flow Fluctuation Curve

Flow-fluctuation Curve

Graph of %ADT versus Time usually for a 24 hour period

Importance of Flow-fluctuation Curve

24 hour flow fluctuation curve gives

• Peak Hour Factor (PHF)

• Design Hourly Volume (DHV)

DHV = PHF x ADT

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Flow Fluctuation Curve ( PCU/hr)F

low

Rate

PC

U/A

DT

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Flow Fluctuation Curve (% of ADT vs Time)

Flo

w R

ate

PC

U/H

R

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Flow Fluctuation Curve

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Our analyzed curve is so far different from what a

actual curve looks like. Here, in Figure 5.2

we can see that, usually we get 2 two peak values of

ADT. From the analysis value we get the

maximum ADT from East to West is 5.93% and

maximum ADT from West to East is 5.81% ADT.

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Conclusions

Recommendations

Limitations

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Conclusions

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Scope for Further Study

This volume study was practiced by un-skilled enumerators, which may lead to

some error in data collection process. values are not amenable to easy analysis

by computers

Data collected by manual method of counting, which is unreliable and

irreversible, more representatives and reliable data could be obtained if

automatic data collection method were followed.

For continuous and long term study , maual metod is not suitable.for authentic

value, automatic device is needed.

The composition of traffic stream varies from site to site. Specific vehicular

movements such as left turns, right turns, sraight- aheads etc are not recorded.

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.

The ADT and AADT value are not analysed . Short term variations occuring in the

course of a day , and especially the peaking situations in the morning and

evening rush hours are needed for design of traffic control systems are

complicated intersections.54

Limitations of the study

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.

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Recommendations

This road mainly served the purpose of collector road. Collector roads should

be designed for a level of service C or better.From the data analysis , we can

see the Level of Service is C

The traffic flow is stable with marked restriction

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

Manual count method required trained enumerators, which was not available

in this case

For more reliable data automatic data collection process should be used.

Data were collected for 20 minutes by each group, which may not represent

the hourly fluctuation of traffic, so for more allegorical data one hour data

should be taken.

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Thank you.

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