I recommend working with the bigger network (tuning individual junctions as necessary). It is always easier to cut out a smaller scenario from a bigger one than assembling a big scenario from smaller ones.
The effect of multiple intersections is noticeable when some junctions are over-saturated. Then the jams grow upstream and affect other junctions as well.
However, if you don't have high traffic and the junctions are far away from each other than it doesn't matter too much.
For pedestrians, it depends:
- pedestrians may block turning traffic that has green when the pedestrians can cross.
- pedestrian phases (i.e. a pedestrian scramble) may reduce the green time for cars
