The stop$-$controlled junction in Question $1$ has then been upgraded to a roundabout in $2024.$

However, due to the high projected traffic volume, it will be converted into a signalized

intersection after $10$ years. The layout of the roundabout is as shown in Figure $2.$ The projected

peak hour flow rate for the roundabout is as shown in Table $2$ and the saturation flow is shown

in Table $3.$ Annual growth rate is $2\mathrm{.}5\%$ and assume amber time $=3s,$ all$-$red interval $=2s$ and

lost time per phase is $2s.$

$($a$)$ Sketch the layout of the signalised intersection based on the direct conversion of the

roundabout to signalized intersection.

$($b$)$ Propose the signal phasing and sketch the ring diagram. Based on Arahan Teknik $($Jalan$)$

method:

Design the signal timing for year $2034$:

Calculate values of $\frac{q}{S}.$

Determine the optimum cycle length, given:

$C_o=\frac{1\mathrm{.}5L+5}{1-Y}$

Determine the green time setting and sketch the timing distribution diagram.

$($c$)$ If the signalized intersection has reached its capacity after $5$ years, propose other possible

solutions that can be implemented to improve the level$-$of$-$service and provide

justification for the proposed solution.

$(20$ marks$)$

Table $2$: Peak hour flow rate for roundabout

for the year $2024$

Table $3$: Saturation flow

Figure $2$: Layout of roundabouthelp