Question

A road 7.5 m wide is one way and has design speed of 75 kmph. Average length of vehicles is 8 m and reaction time to stop the vehicles is 2 sec. Theoretical capacity of the road will be (take f = 0.35)

Answer 1

$W=7.5m\text{(two lane)}$
$V=75kmph$
$t_0=2sec$
$l=8m$
Minimum centre to centre spacing between the vehicles (S) is
$S=8+75\times \frac{5}{18}\times 2=49.67m$

Theoretical capacity
$C=\frac{1000V}{S}=\frac{1000\times 75}{49.67}$
$C=1509veh/hr/lane$

Road is two lane
So, theoretical capacity
$C=2\times C=3018veh/hr$