@Thadian: This is just a prefab. The beauty of this game is being able to add to and change almost anything... But it is also why I tagged this as a residential zone, even though it can be used for anything.
The idea behind the ped overpasses is to reduce pedestrian traffic, which will reduce overall traffic because they don't cause traffic lights to turn red in order for them to cross the road.... This will also mean service vehicles will be able to reach them without much interruption, even though the travel times might be longer than normal. This is by design.

If you're unhappy with it, change it, or make suggestions on how to improve :)

All those long avenues will make a long time before turning around, which will complicate service.