Traffic volume is a fundamental measure of traffic on a road system, measured as the number of vehicles crossing a section of road per unit time. It is used for various purposes like planning, design, and traffic management. There are manual and automatic methods to count traffic volume. Manual methods involve field observers counting and classifying vehicles in different time intervals, while automatic methods use technologies like pneumatic tubes buried in roads, inductive loops in pavements, and radar to detect vehicle presence and count traffic volume without human observers. The collected data is then analyzed to produce traffic flow maps, intersection diagrams, and trend charts to understand traffic patterns and inform transportation planning.

1. 1
PRESENTED BY
AGLAIA

2. • Traffic Volume :- Number of vehicles crossing a section of
road per unit time at any selected period.
• One of the fundamental measures of traffic on a road
system.
• Used as a quantity measure of flow.
• Unit: vehicles per day and vehicles per hour.
• Classified traffic volume count
2

3. Scopes of Volume Study
SCOPES
Design
Planning
Improvement
Dynamic
Traffic
Management
Estimating
Highway
Use
Computing
Accident
Rates
Traffic
Stream
3

4. • Measure of relative importance of roads for deciding the priority for
improvement & expansion.
• Used in planning , traffic operation and control of existing facilities and to
design new facilities.
• For analysis of traffic patterns & trends
• Classified volume is used for structural design of pavements & geometric
design
• For planning one way streets and other regulatory measures.
• Turning movement study for design of intersection , signal timings etc
• Pedestrian traffic volume for planning of side walks, pedestrian signals etc.
4

5.  Employs a field team to count and classify traffic volume.
 No. of observers required depends upon no. of Lanes
and type of information required.
 More desirable to record traffic in each direction of travel
by posting separate observers for each direction.
 For all-day counts ,work in three shifts of 8 hrs can be
arranged.
 Data is recorded by Five- dash system. (IIII)
5

6.  Manual counts are typically used for periods of less than
a day. Normal intervals for a manual count are 5, 10, or
15 minutes.
 Traffic counts during a Monday morning rush hour and a
Friday evening rush hour may show exceptionally high
volumes and are not normally used in analysis
 counts are usually conducted on a Tuesday, Wednesday,
or Thursday
6

7. 7

8. Survey Procedure
8

9. Vehicle Type Tally
Car
CNG
Bus
Motorcycles
NMT
9

10. 10
ADVANTAGES
 Details such as vehicle classification and no. of occupants can
be obtained.
 Records Turning movement data of vehicles at intersections.
 Analyzing traffic characteristics in unusual conditions such as
adverse weather conditions, traffic breakdowns, temporary
closure of any lane of highway etc.
 Comparatively cheaper method of counting.
 It is often necessary to check the accuracy of automatic
devices
 Data accumulated by manual methods are easy to analyze.

11. DISADVANTAGES
• Not practicable to have manual count for 24 hrs of the day
and throughout the year.
• Counts of remote areas is possible by automatic devices.
11

12. Multiple Pen Recorder
• A chart moves continuously at the speed of a clock.
Different pens record different events.
• Actuation of pen is by pressing the corresponding electric
switch.
• When a particular class of vehicle passes ,the associated
switch may be pressed and this operates the pen on the
channel.
• This represents the arrival of that particular class of
vehicle.
12

13. ADVANTAGES
• Permanent record is kept about arrival of each class of
vehicle.
• Classification and vehicle count are performed
simultaneously.
13

14. 1. Pneumatic Tube
• Flexible tube with one end sealed is clamped to
road at right angles to pavement.
• Other end connected to a diaphragm actuated
switch.
• When an axle of vehicle crosses the tube, a
volume of air gets displaced thus creating a
pressure which closes the electrical contact
through switch.
• Two such contact result in one count.
14

15. Disadvantages
• When vehicles with more than two axles are present.
• Tubes get damaged by crawler tractors, tyre chains etc.
• Difficulty in fixing them to gravel surfaces.
15

16. 16

17. 17
Figure : Pneumatic Road Tube

18. • A pair of steel strips are contained in a rubber pad which
is buried beneath the surface.
• When vehicle passes over rubber pad ,steel strips come
into contact with each other and electric current flows.
• Electric contact devices are installed in each lane.
18

19. • A coaxial cable is clamped across the road surface,
• signals are generated when vehicle passes over it.
• Signals actuate the counter.
• Advantage : lesser susceptibility to damage.
19

20. • On one end of road , a source of light emits a beam across
the road.
• At the other end is a photo –cell which can distinguish
between the light beam and absence of light beam.
• Passage of vehicle in the path of light beam obstructs the
beam and detected by photo-cell.
Disadvantages
• Obstruction can be caused by pedestrians also.
• More than one vehicle positioned in the beam line
simultaneously can register as one vehicle.
20

21. 21

22. • Based on Doppler Effect.
• Compares the frequency of a transmitted radio signal
with the frequency of the reflected signal.
• When a moving vehicle interrupts the signal , a
frequency difference exists.
22

23. 23
Radar

24. • 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.
24

25. 25

26. • Traffic Flow Maps:
• Show volume along various routes by using bands proportional to
traffic volume carried.
• Thickness of lines represent traffic volume.
• Intersection Flow Diagrams
• Give direction and volume of traffic through an intersection.
• Trend charts
• Shows the hourly , daily or monthly changes in volume through an
area.
• Useful for planning future expansion, design and regulation.
26

27. 27
Traffic Flow Maps:
Intersection Flow Diagrams
Trend charts

28. Thank you
Lintels
For more…. Mail to aglaiaconnect2018@gmail.com