Flow (Volume) (Q)
The number of vehicles passing a specified point during a stated period of time is called flow. It is usually expressed in vehicles per hour.
For examples,
At a particular section of road, if 600 vehicles passes in a time period of 1 hour, then the flow or traffic volume is 600 vehicles/hour. Maximum possible flow is traffic capacity.
AADT (Average Annual Daily Traffic)
It is the average of 24 hours volume count collected every day in the year.
∴ AADT = Total annual flow/365
It is useful for,
- Computing accident rates
- Estimating highway user revenue
- Planning major streets
- Improvement, construction or reconstruction of roads
Journey speed (Travel speed or Overall speed)
It is the effective speed with which a vehicle traverse a particular route between two stations.
Journey speed = Total distance travelled/Total time taken(including delays)
