Question

You are observing traffic in a single lane of a highway at a specific location. You measure the average headway and average spacing of passing vehicles as 3 seconds and 150 feet, respectively. Calculate the flow, speed and density of the traffic stream in this lane.

Answer 1

Answers:

1) flow of traffic =   $1198.8 veh/h$

2) average speed = $34.09 mi/h$

3)density of traffic = $34.34 veh/mi$

Explanation:

1) to find flow of traffic

we use the relation

$q=1/h$

where q is the traffic flow and h is average time headway.

$h= 3s$       $(given)$

insert the value

$q=1/3=0.333veh/s=1198.8veh/h$

2) to find average traffic speed

use the relation

$u=S/h$

where u is average speed S is average spacing and h average time

$S= 150 ft$   $(given)$

so inserting the values

$u= 150/3*3600/5280=34.09 mi/h$

3) density of traffic

$K=q/u$

where K is density of traffic q is flow of traffic and u is average speed

inserting values from above solved parts

$K=1198.8/34.09=34.34 veh/mi$