Density Bar – what happens when it completely fills

Does the capacity of the road influence how many agents can travel down it simultaneously?

No. Number of lanes and whether there are stop signs or traffic lights only affect traffic agents. They do not affect non-traffic agents.

• Traffic agents include police, fire, ambulance, garbage trucks, delivery trucks, moving trucks and of course sims driving their cars.
• Non-traffic agents include power, water, sewage and of course pedestrian sims.

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.

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Update: There was a sewage issue fixed in patch 1.8.

Fixed a clog in the pipes where sewage would sometimes get backed up and act jittery.

In SimCity, there are two different types of road. These are streets and avenues.

Streets are one square wide and avenues are two squares wide. All streets are the same width, so a dirt road can be upgraded to a high density street using the upgrade road tool.

In order to upgrade a street to an avenue, however, you need to destroy the old street and replace it with a larger avenue, which will remove all infrastructure that exists along the old street.

If you're in a situation where you already have the maximum capacity version of a particular style of road but don't have the space to replace it with an avenue, there are other options available. It is possible to build additional roads within the vicinity to alleviate the amount of traffic travelling down your currently over-crowded road. To do this, bring up the traffic data layer to see where all of the traffic is coming from, and build new roads that intersect the busiest streets to provide additional routes for your sims to travel down. The traffic data layer can be accessed using the 'All Data Maps' button in the bottom right of the interface, or by toggling the 'upgrade road' option.

In addition, there is the possibility of setting up mass transit. Mass transit works by building a depot (and adding additional trucks as required to increase the number of sims that can travel per day and reduce the wait time for busses) and placing stops. The region that a stop will cover is highlighted along the roads as you place the stops. For the maximum effect you will want to place stops along your busiest streets (see your data layer for traffic again) and ensure that the wait time for passengers is managed to ensure it doesn't get too high.

You can monitor wait time by bringing up the information screen for your mass transit depot, and you can monitor the amount of traffic a particular stop is attracting by bringing up the information screen for each individual stop.