Page 96 - HIGHWAY ENGINEERING LABORATORY_FLIP BUILDER

Page :
WORK INSTRUCTION
Edition :
Checking No.
TRAFFIC VOLUME STUDY
(Reference Standard:
CIVIL ENGINEERING AASHTO. 2001) Effective Date:

JKA/ DCC30112/ 2021 Amendment Date:

1.0 OBJECTIVE OF EXPERIMENT :

1. To determine vehicle composition in the traffic flow stream.
2. To observe the traffic flow trend and movement pattern

3. To estimate hourly volume and average daily traffic (ADT)

2.0 SUMMARY OF THEORY :

Traffic volume can be defined as the number of vehicle or pedestrians passing as a
given point on a lane or carriageway during a specified period of time. Traffic volume
studies are widely known as traffic counts and they are carried out to determine the

basic traffic data such as the number (volumes), classifications and directional
movements of roadway vehicles and pedestrians at a selected location. Traffic
volume data can assist in determining traffic flows or flow rates which describe the

number of vehicles or pedestrians per unit time passing (arriving or departing) a given
reference point.

The various volume counts taken over different lengths of time are usually expressed in
vehicles per hour (vph). Other traffic volume characteristics obtained are average

annual daily traffic (AADT), average daily traffic (ADT), peak hour volume (PHV), and
vehicle miles of travel (VMT). The documentation of volume trends, critical flow time
periods and the influence of heavy andslowvehicles or motorcyclists or

pedestrians on overall vehicular traffic flow can be illustrated.

The sampling period depends very much on the intended use of the data recorded,
the resources available to the counting agency, the nature of the location being
studied and the type of count. Counting can be done from as low as 5-minute

intervals to as much as a year. In these studies, both manual and automatic counts
are included in Part 1 and Part II respectively

Higway Engineering Laboratory page 81