ShetLand:
Not that it's germane to you getting it to work according to the rules, but Rule#1 is insane. The whole point of a traffic light is to let the cars in the side road out every now and then, even though the main road is busy; indeed especially when the main road is busy.
I was thinking the assignment was a crawl before walking.
if you cannot make this part work, the complications associated with good traffic control would be overwhelming.
Also, the assignment is clear enough that getting it done will reveal to the professor what needs to be addressed and what was missed in the lectures.
it was clear in his truth table that he did not follow the rules set forth.
since he was unable to complete this task, adding multiple layers of complexity would not be good teaching.
I would expect that the professor has those layers as phase-II and phase-III so that by the end of the class, the professor walked the students along the path and they all came out with true knowledge of the work.