$98-$Civ$-$B$10$ December $2015$

Traffic Engineering

Page $4$ of $4$

$6.$ An isolated intersection with 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 below for flow information for the intersection:

$\backslash$table$[[\backslash$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 veh $\frac{?}{h},pc\frac{u}{h},$ and persons per hour for all directions.

$($b$)$ The basic saturation flow rate for the intersection is $2200pc\frac{u}{h},$ calculate the adjusted saturation flow rate in veh$/$h for all approaches.

$($c$)$ The cycle is a $2-$phase operation with a standard amber interval of $3\mathrm{.}0s$ and a clearing speed of $36k\frac{m}{h}.$ The average length of a passenger vehicle is $6\mathrm{.}0m$ long. Calculate the all red interval, the intergreen period, and the intersection lost time.

$($d$)$ Calculate the intersection flow ratio