Vehicles Traffic Flow and Density
Traffic flow and density as used in highway design.
Vehicle Traffic Flow
The vehicle traffic flow on a road can be expressed
q = n 3600 / t (1)
where
q = vehicle flow (no. vehicles per hour)
n = no. vehicles passing in t seconds
t = time for passing vehicles (s)
Example - Vehicle Traffic Flow
If 1000 vehicles passes in 2 hours (7200 s) - the flow can be calculated
q = (1000 vehicles) (3600 s/h) / (7200 s)
= 500 vehicles/h
Vehicle Density
Vehicle density can be expressed as
k = n 5280 / l (2)
where
k = vehicle density (vehicles per mile)
n = no. of vehicles occupying a length l of the road
l = the length of road occupied by the vehicles (ft)
(2) expressed in km
k = n 1000 / l (2b)
where
k = vehicles per km
n = no. of vehicles occupying a length l of the road
l = the length of road occupied by the vehicles (m)
