Transportation Engineering presentation Topic: 1.Roadway Condition Survey 2. Traffic Volume Study

2. Ahsanullah University of Science And Technology
Department of Civil Engineering
Course No: CE 452
Course Name: Transportation Engineering Lab-II
4th Year 2nd semester (Section: B)

3. A
Presentation
oN
Traffic Volume Study

4. Presented By: Group-03
Group members:
1. Tasrufa Tahsin (11.01.03.074)
2. Md. Salim Mia (11.01.03.075)
3. Faruk Patowary (11.01.03.079)
4. Rumana Samad (11.01.03.082)
5. Aqib Jishan (11.01.03.112)
6. Raqib Al Mahmood (11.01.03.115)
7. Mizanur Rahman Sharif (09.01.03.002)
8. Farhan Shihab (10.01.03.085)

5. Traffic Volume Study
What is traffic volume Study?
Traffic Volume Study: The term traffic volume study is also known as traffic flow
survey or simply the traffic survey. It is defined as the procedure to determine
mainly volume of traffic moving on the roads at a particular section during a
particular time. Volume is basically number of vehicles or persons passing a point
during a specified time period which is usually one hour but may be less than that. It
means during a period of time, it may be fifteen minutes, it may be half an hour, it
may be even sixty minutes or one hour and how many vehicles or persons are passing a
point during that particular time period is known as volume. Traffic volume study is
used for traffic planning of a particular road or area. Traffic stream composition of
a particular road can be known from traffic volume study.

6. Objectives of traffic volume study
General
Objectives
Geometric
Design Of
The Roadway
Dynamic
Traffic
Management
And Control
Traffic
Planning
Improvement
Of The Level
Of Service Of
The Roadway

7. Scope of traffic volume study
To Check The Existing Level Of
Service Of The Road
Magnitudes, Classification,
Proportion And Directional
Distribution Of Vehicular Flow
Study Of The Flow Fluctuation
Of Different Approaches
Traffic Design, Planning And
Control Measures
Scope

8. Some important definitions related to traffic volume study
Average Daily Traffic (ADT): Average daily traffic or ADT, and sometimes also mean daily traffic, is the average number of
vehicles two-way passing a specific point in a 24-hour period, normally measured throughout a year. ADT is not as highly
referred to as the engineering standard of AADT which is the standard measurement for vehicle traffic load on a section of
road, and the basis for most decisions regarding transport planning, or to the environmental hazards of pollution related to
road transport.
Annual Average Daily Traffic (AADT): Annual average daily traffic, abbreviated AADT, is a measure used primarily in
transportation planning and transportation engineering. Traditionally, it is the total volume of vehicle traffic of a highway or
road for a year divided by 365 days. AADT is a useful and simple measurement of how busy the road is. Newer advances
from traffic data providers are now providing AADT by side of the road, by day of week and by time of day.
Passenger Car Equivalent (PCE): Passenger Car Equivalent (PCE), is a metric used in Transportation Engineering to assess
traffic flow rate on a highway. A Passenger Car Equivalent is essentially the impact that a mode of transport has on traffic
variables (such as headway, speed, density) compared to a single car. Highway capacity is measured in PCE/hour daily.
Passenger Car Equivalent is also sometimes used interchangeably with Passenger car unit (PCU).

9. Some important definitions related to traffic volume study
Directional Distribution (DD): The directional distribution is simply the distribution or split of total traffic volume in two
opposite directions in particular time period. It is commonly expressed in terms of percentage of total traffic in the heavier
direction of travel.
Average Weekly Traffic (AWT): It is the average of 24-hour traffic volume which is occurring on weekdays for some period
less than one year.
Annual Average Weekly Traffic (AAWT): AAWT is the average 24-hr traffic volume occurring on weekdays over a full
365-day year.
Design Hourly Volume: It is the economic hourly flow of future year, which is used for designing geometric features of
roadway. It is chosen in such a way that during the design period it should not be exceeded too often or too much.
Rate of Flow: Rate of flow is used to express an equivalent hourly rate for vehicles passing a point along a roadway or for
traffic during an interval less than 1-hr (usually 15min).
Saturation flow: The maximum hourly rate of an approach at a signalized junction.

10. Some important definitions related to traffic volume study
Service flow rate: The maximum hourly rate of traffic flow of a roadway section during a given period under prevailing roadway
condition.
Forced flow: When lane changing opportunity decreases with increasing traffic volume and drivers are forced to follow slow leaders.
Free flow: When drivers face no restriction in driving and can maintain their desired speeds.
Peak flow: Flow at peak periods.
Off-peak flow: Flow at off-peak/lean periods.
Stable/ Steady flow: When demands are well below the roadway capacity and the average rate of flow remains almost constant with
time.
Unstable flow: When demand is at or near or exceeds the roadway capacity and the average rate of flow fluctuates largely with time.
Contra flow: For repair works; an arrangement on a large road by which traffic going in both directions uses only one side of the
road. For bus priority; a special arrangement on one-way street by which only bus is allowed to go in opposite direction.
Tidal flow: When traffic flows in both direction exhibit unbalanced characteristics at peak periods viz. morning rush at in-bound lanes
due to commuter traffic and in the evening the same is true for the out-bound lanes.

11. Traffic Volume count
Traffic volume counts are basic to all phases of highway development and operation. No other single reference
tells an engineer as much about a road as the number of vehicles which use it.
Traffic counts are the major source of traffic data. Traffic counts are very specific in that they only apply to one
location and to the time period for which they have been obtained. Some of the major types of traffic counts in
general use by engineers are annual counts, peak hour counts, turning movement counts and classification
counts.
Methods of traffic volume count
1. Manual observation
2. Automatic recording

12. Manual observation
 Counting is done by trained personnel
 Used when the effort and expense of automated equipment are not justified
 Used to gather data for determination of vehicle classification, turning movements,
direction of travel, pedestrian movements, or vehicle occupancy
 Usually used for counting period less than a day

13. Manual Count Recording Methods
Manual counts are recorded by using one of the following three methods:
1. Tally Sheets
2. Mechanical Counting Boards
3. Electronic Counting Boards
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

14. 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. Typical counters are push button devices with
three to five registers. Each button represents a different
stratification of type of vehicle or pedestrian being counted.
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.
Electronic counting boards are lighter, more compact, and easier
to handle. They have an internal clock that automatically
separates the data by time interval. Special functions include
automatic data reduction and summary. The data can also be
downloaded to a computer, which saves time.

15. Automatic recording
 Counting is done by sophisticated electronic
devices and detectors
 Used for gathering large amount of traffic
data
 Used when the effort and expense of
automated equipment are justified
 Counting is usually done in 1 hour intervals
for each 24 hours period
 Counting may be done continuously for a
week, month or a year

16. Automatic Count Recording Method
Automatic counts are recorded using one of the following three methods:
1. Portable Counters
2. Permanent Counters
3. Videotape.
Portable Counters:
Portable counting is a form of manual observation. Portable
counters serve the same purpose as manual counts but with
automatic counting equipment. The period of data collection
using this method is usually longer than when using manual
counts. The portable counter method is mainly used for24-
hour counts. Pneumatic road tubes are used to conduct this
method of automatic counts.

17. Permanent Counters:
Permanent counters are used when long-term counts are to
be conducted. The counts could be performed every day for
a year or more. The data collected may be used to monitor
and evaluate traffic volumes and trends over a long period
of time. Permanent counters are not a cost-effective option
in most situation. Few jurisdictions have access to this
equipment.
Videotape:
Observers can record count data by videotaping traffic.
Traffic volumes can be counted by viewing videotapes
recorded with a camera at a collection site. A digital clock
in the video image can prove useful in noting time
intervals. Videotaping is not a cost-effective option in most
situations. Few small jurisdictions have access to this
equipment

18. commonly used detectors in automatic counting
Pneumatic Tubes
These are tubes placed on the top of road surfaces at
locations where traffic counting is required. As vehicles
pass over the tube, the resulting compression sends a
burst of air to an air switch, which can be installed in any
type of traffic counting devices. Air switches can provide
accurate axle counts even when compressions occur more
than 30 m from the traffic counter.
Inductive Loops
Inductive loop detector consists of embedded turned wire
from which it gets its name. It includes 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. Inductive loops are cheap, almost
maintenance-free and are currently the most widely used
equipment for vehicle counting and detection.

19. commonly used detectors in automatic counting
Weigh-in-Motion Sensor
A variety of traffic sensors and loops are used world-wide to count,
weigh and classify vehicles while in motion, and these are collectively
known as Weigh in Motion (WIM) sensor systems. Whereas sensor
pads can be used on their own traffic speed and axle weighing
equipment, they are trigged by “leading” inductive loops placed before
them on the roadbed.
Radar Detectors
Radar detectors actively emits radio-active
signals at frequencies ranging from the
ultra-high frequencies (UHF) of 100 MHz to
100 GHz and can register vehicular presence
and speed depending upon signals returned
upon reflection from the vehicle.

20. Types of volume count
1. Cordon Counts:
When information is required on vehicle accumulation
within an area, such as the central business district (CBD)
of a city, particularly during a specific time, a cordon count
is undertaken. The area for which the data are required is
cordoned off by an imaginary closed loop; the area
enclosed within this loop is defined as the cordon area.
2. Screen Line Counts:
In screen line counts, the study area is divided into large
sections by running imaginary lines, known as screen
lines, across it. In some cases, natural and man-made
barriers, such as rivers or railway tracks, are used as
screen lines. Traffic counts are then taken at each point
where a road crosses the screen line. It is usual for the
screen lines to be designed or chosen such that they are
not crossed more than once by the same street.

21. Types of volume count
3. Cordon and Screen Line Counts:
Both Cordon and Screen Line counting methods are done
simultaneously
4. Intersection Counts:
Intersection counts are taken to determined vehicle
classification through movements and turning
movements at intersections. These data are used mainly
in determining phase lengths and cycle times for
signalized intersections, in the design of channelization
at intersections, and in the general design of
improvements to intersections.

22. Types of volume count
5. Pedestrian Volume Counts:
Volume counts of pedestrians are made at locations
such as subway stations, mid-blocks, and crosswalks.
The counts are usually taken at these locations when
the evaluation of existing or proposed pedestrian
facilities is to be undertaken. Such facilities may
include pedestrian overpass or underpasses.
6. Periodic Volume Counts:
In order to obtain certain traffic volume data, such as AADT, it is necessary to obtain data continuously.
However, it is not feasible to collect continuous data on all roads because of the cost involved. To make
reasonable estimates of annual traffic volume characteristics on an area-wide basis, different types of
periodic counts, with count durations ranging from 15 min to continuous, are conducted; the data from
these different periodic counts are used to determine values that are the used to estimate annual traffic
characteristics.
The periodic counts usually conducted are continuous, control, or coverage counts.

23. Key steps of Manual and Automatic Count
Perform Necessary Office
Preparations
Select Proper Observer Location
Label Data Sheets And Record
Observations
Perform Necessary Office
Preparations
Deploy And Calibrate Data
Collection Equipment
Check Data And Retrieve Equipment
Manual Method Automatic Method

24. Traffic volume study location
Panthapath to Russel Square Link Road

25.  Method of Counting : Manual
 Equipment Used for Counting
 Stopwatch
 Handmade Data Sheets
 Pencil
 Clipboard
 Hand Tally Counter
 Number of Enumerator
There were 8 enumerators in the group. Individual was appointed to count one or more than one classified
vehicles.

26. Collected Data
Date : 30 January, 2014
Day : Thursday
Time: 11:00-11:30 am
Counting Period: 30 min
Group No : 3
Direction: Panthapath to Russell Square
Location : Russell Square Intersection
Weather Condition: Mild and sunny
Vehicle Classification Observed Vehicle No
Bus 3
CNG 112
Car 240
Jeep, Microbus, Ambulance 145
Motorcycle (MC) 145
NMV 350
Utility 20
Truck 3
Total = 1018

27. Traffic Stream Composition
(Panthapath to Russel Square link Road)
Number of Different Vehicles Percentage of Different Vehicles

28. Service flow rate
(Panthapath to russel square link road)
Service Flow Rate = 1545.5 PCU/hr ≈ 1546 PCU/hr

29. Level of service (LOS)
Group: 03
Level Of Service (LOS) Service Flow Rate (PCU/Hr)
A 600
B 700
C 900
D 1200
E 1400
F >1400
Service flow rate of different groups

30. ADT and AADT (East to West)
Provided Values:
HEF (9:00-10:00 am) = 18.80
HEF (10:00-11:00 am) = 17.11
HEF (11:00-12:00 pm) = 18.52
DEF (Thursday) = 7.012
MEF (January) = 1.756
Estimated 24-hr volume for Thursday using HEF = (1346*18.80+1405*17.11+1546*18.52)/3
= 25992.09 PCU/24-hr
≈ 25992 PCU/24-hr
Adjust the 24-hr volume for Tuesday to an average volume for the week using the daily expansion factors.
Total Weekly Volume = 25992*7.012
= 182255.9 PCU/week
≈ 182256 PCU/week
Average 24-hr volume or Average Daily Traffic, ADT (East to West) = 182256/7
= 26036.57 PCU/24-hr
≈ 26037 PCU/24-hr
Annual Average Daily Traffic, AADT (East to West) = 26037*1.756
= 45720.97 PCU/day
≈ 45721 PCU/day

31. ADT and AADT (West to east)
Estimated 24-hr volume for Thursday using HEF = (1822*18.80+1672*17.11+1682*18.52)/3
= 31337.39 PCU/24-hr
≈ 31337 PCU/24-hr
Adjust the 24-hr volume for Tuesday to an average volume for the week using the daily expansion factors.
Total Weekly Volume = 31337*7.012
= 219735.04 PCU/week
≈ 219735 PCU/week
Average 24-hr volume or Average Daily Traffic, ADT (West to East) = 219735/7
= 31390.71 PCU/24-hr
≈ 31391 PCU/24-hr
Annual Average Daily Traffic, AADT (West to East) = 31391*1.756
= 55122.59 PCU/day
≈ 55123 PCU/day

32. Directional distribution
From the π-Diagram it is seen that 54.64% vehicles of total
traffic volume go from West to East while 45.36% vehicles
go from East to West. It signifies that in a day more
vehicles travel from Dhanmondi residential area to
Panthapath and Sonargaon commercial area than from
opposite direction. Directional distribution also varies
during morning and evening due to commuter traffic.
Direction Time PCU/hr Avg.
PCU/hr
Directional
Distribution
E to W
9:00-9:30 am 1346
1432.33 45.36%10:30-11:00 am 1405
11:00-11:30 am 1546
W to E
9:00-9:30 am 1822
1725.33 54.64%10:30-11:00 am 1672
11:00-11:30 am 1682

33. Flow fluctuation
On a given roadway, the volume of traffic fluctuates widely with the time. Such variations during a day, week or year
tend to be cyclical and to some extent predictable. The nature of the pattern of variation depends on the type of road
facility. Urban arterial flow is, for example, characterized by pronounced peaks during the early morning and late afternoon
hours, due primarily to commuter traffic. Rural roads tend to experience less pronounced daily peaks, but they may
accommodate heaviest traffic flow on weekends and holidays because of recreational travel. Flow fluctuation curve of a road
represents the variation of flow throughout a day. 24-hr traffic volume data is required to develop a flow fluctuation curve.
Flow fluctuation analysis
Time East to West
(Flow Rate, PCU/hr)
West to East
(Flow Rate,
PCU/hr)
East to West
(ADT)
West to East
(ADT)
East to West
( % of ADT )
West to East
( % of ADT )
9:00-10:00 am 1346 1822
26037 31391
5.17% 5.80%
10:30-11:00 am 1405 1672 5.40% 5.33%
11:00-12:00 pm 1546 1682 5.94% 5.36%

34. Flow fluctuation curve
(Panthapath to Russel Square link road)
5.10%
5.20%
5.30%
5.40%
5.50%
5.60%
5.70%
5.80%
5.90%
6.00%
%ofADT
9:00-10:00 AM 10:00=11:00 AM 11:00-12:00 PM
% Of ADT VS TIME
East to West West to East
From the % Of ADT VS TIME flow
fluctuation curve it is seen that during time
period 9:00-10:00 am, percentage of ADT
passing from West to East is greater than
East to West and gradually decreases with
time. On the other hand, percentage of
ADT from East to West is minimum at this
period and increases with time. During
10:00-11:00 am, the percentage of ADT
from both East to West and West to East is
more or less same.

35. 0
200
400
600
800
1000
1200
1400
1600
1800
2000
9:00 - 10:00 A M 10:00 - 11:00 A M 11:00 - 12:00 A M
FLOWRATE(PCU/HR)
TIME
FLOW RATE VS TIME
East to West West to East
Flow fluctuation curve
(Panthapath to Russel Square link road)
In the FLOW RATE VS TIME flow
fluctuation graph, we see that the service flow
rate from West to East is always greater than
the service flow rate from East to West. It
signifies that volume of vehicles travelling
from Russel Square to Pathapath direction is
always remains greater than the opposite
direction. It is also seen from the graph that
in both direction a peak is observed during
the period 9:00-10:00 am. This morning peak
occurs due to commuter traffic travelling
from nearby residential areas.

36. Recommendations
 Non Motorized Vehicles (NMV)
Shouldn’t Be Allowed In This
Road
 Road Side Parking Should Be Banned or Toll
May Be Collected To Discourage Parking

37. Recommendations
 Amount Of Public Transport Should Be
Increased
 Road Side Non-motor Activities Should be
Prohibited

38. Recommendations
 Scattered And Haphazard Pedestrian
Crossing Should Be Discouraged And
Prohibited
 Foot Over Bridges Should Be Constructed At
Important Points For Pedestrian Crossings

39. Recommendations
 Optimum traffic signal system should be introduced
 During rush hours or tidal flow, lanes may be rearranged
 Number of lanes should be based on directional distribution
 Signal timing should also be set from directional distribution
 Entry of NMV should be restricted during peaks obtained from flow
fluctuation curve
 Right of way may also be restricted to avoid congestion

40. Limitations
 Limited and unskilled enumerators.
 Time and Resources are Limited
 Insolent Surveyors
 Manual method of counting, which is unreliable and irreversible
 Short-term (30 minute) data collection
 CCTV footage or Camera recording is not available
 Expansion factors used for the calculation of ADT were developed
for a rural primary road.
 Proper enforcement of traffic regulation is not obtained
 For Flow Fluctuation Curve weekly 24 hours is needed. But due to
time and manpower constraint it was not possible.