Answer Happy

QUESTION TWO Details of an existing signalised intersection are shown below. Figure 1 shows the geometry, Figure 2 shows the phasing and Figure 3 shows the traffic volumes. Calculate the degree of saturation for this intersection using the following assumptions: ● Saturation flows are 1800 tcu/h in all lanes ● Intergreen time = lost time = 6 seconds for all phases No movements are restricted USE ATTACHMENT 1 FOR YOUR CALCULATIONS SUBMIT ATTACHMENT 1 WITH YOUR EXAM BOOKLET Formulae are provided in ATTACHMENT 1 ↑↑r Ver Figure 1 Signalised Intersection Layout [9 Marks]

QUESTION TWO......cont. Phase A Phase B Phase C Figure 2 Signalised Intersection Phasing 1000 vph (60) 200 vph (5) T Volumes are in total vehicles per hour. Number in brackets is the number of Heavy Vehicles. 240 360 vph vph (8) (20) Figure 3 - Signalised Intersection Volumes 1200 vph (60) 270 vph (20)

ATTACHMENT 1 (QUESTION TWO-TRAFFIC ENGINEERING) HAND IN ATTACHMENT 1 WITH YOUR EXAM BOOKLET STUDENT NAME AND ID NUMBER Movement Phase Arrival y = q/s Critical y Critical g q (tcu/h) Saturation Flow, s (tcu/h) Lost Time, / Critical lost time g for all movements Flow (vph) Capacity Q Y = L= ag = Optimum cycle time is given by: Effective green time of critical movements is given by: (1.4 + k) L+6 Co= 1 - Y D of S, X

Use k = 0.2 g=(c- L) ² /