In SimCity each entity in the game world is called an 'agent', and each agent travels down roads seeking out other entities that require an agent of that particular type. An agent can be anything from the power from your power plant or a Sim travelling to work.
The screenshot below shows sewage:
I have two sewage structures next to each other at the bottom of a low density street and I'm being told that there is not enough capacity to deal with the current level of sewage, however if I bring up the information for the sewage structures, neither of them are operating at 100% capacity – so I'm wondering: does the capacity of the road influence how many agents can travel down it simultaneously?
Best Answer
No. Number of lanes and whether there are stop signs or traffic lights only affect traffic agents. They do not affect non-traffic agents.
Power and water agents are absorbed as they pass buildings with available capacity. While the agents aren't affected by road capacity, they can be depleted by passing many buildings. If you layout your city with a powerplant at position 1, it is unlikely that agents will reach buildings at position 2.
Update: There was a sewage issue fixed in patch 1.8.