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1. 1 TRAFFIC VOLUME STUDY 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 TRAFFIC VOLUME

3. Scopes of Volume Study 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 USES OF TRAFFIC VOLUME

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 MANUAL METHOD

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

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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. COMBINATON OF MANUAL & MECHANICAL METHOD 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. Automatic devices 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

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17. 17 Figure : Pneumatic Road Tube

18. Electric Contact Devices 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. Coaxial Cables 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. Photo-electric Device 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

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22. Radar 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. Videotape or Videography 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

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26. Presentation of data 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

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