QUESTION $3$

An isolated intersection has four one$-$lane approaches where no turns are permitted. The lanes are all $4m$ wide with $3m$ wide crosswalks in all directions and the vehicles are required to stop $1m$ before the crosswalks. The speed limit is $50k\frac{m}{h}$ for all approaches and there are no grade changes at the intersection. The average passenger car carries $2$

people and the average buses occupancy is $30$ persons per bus in the NB direction and $15$ persons per bus in the SB direction. See the table $1$ for intersection flow information.

Table $1$: Traffic flow data

$\backslash$table$[[$Approach Lane,$\backslash$table$[[$Flow of passenger cars$],[$per hour$]],\backslash$table$[[$Flow of buses per$],[$hour$]]],[$NB$,1000,17],[$SB$,600,10],[$EB$,400,0],[$WB$,800,0]]$

a$)$ Calculate the arrival flow in vehicles per hour, passenger car units per hour and persons per hour for all directions.

b$)$ If the basic saturation flow rate for the intersection is $2200pc\frac{u}{h}r,$ calculate the adjusted saturation flow rate in vehicles per hour for all approaches.

$[07$ marks$]$

c$)$ If the cycle is a $2-$phase operation with a standard amber interval of $3\mathrm{.}0s,$ a clearing speed of $36k\frac{m}{h}$ and the average length of a passenger vehicle is $6\mathrm{.}0m$ long; Compute the following:

i$.$ All red interval,

ii$.$ Inter$-$green period and,

iii. Intersection lost time.

d$)$ Calculate the intersection flow ratio.