(a)

Top Lights	Bottom Lights	Left Lights	Right Lights	Bottom Filter	Top Filter	Left Filter	Right Filter	Time Period
G	R	R	R	0	1	0	0	10

(b)

Top Lights	Bottom Lights	Left Lights	Right Lights	Bottom Filter	Top Filter	Left Filter	Right Filter	Time Period
G	G	R	R	0	0	0	0	10

 

3. How do filters improve the flow of traffic? (1)

4. What does an amber light indicate? (1)

5. What does a red and amber light together indicate? (1)

6. a) What problems might there be with traffic lights that follow a set program all of the time? (1)

6. b) How could the problem in a) be overcome? (1)

7. What is the benefit of having a system that can be run by programming it? (1)

Total (10)

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