Definition of speed | Traffic volume and Traffic rate of flow

Sunday, May 19, 2013 15:29
Posted in category Transportation Engineering
Views: 2,699 views


Distance covered by vehicle in unit time is known as speed.

Its units are miles/hour or km/hr.

Traffic Volume (q)

The actual number of vehicles observed to pass a given point on the highway in a given time is known as traffic volume.

  1. Its units are vehicles/unit time.
  2. We design the width of the road on the basis of peak traffic volume.

Rate of flow of traffic

If 200 vehicles passes in 10 minutes then rate of flow = 200 * 6 = 1200 vehicles/hour.

Traffic volume is different from rate of flow.

For example

Time period

Traffic volume counted (q)

Rate of flow

4 – 4:15


2000 vehicles/hr

4:15 – 4:30


2400 vehicles/hr

4:30 – 4:45


2800 vehicles/hr

4:45 – 5:00


3200 vehicles/hr

2600 vehicles/hr

So from the above example we can see that traffic volume is different from rate of flow of traffic.

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