Roads
Roads provide building frontage, carry trips and connect the city to regional utilities. A building needs an eligible road directly beside its plot. Keep the street network connected to the region through a road, avenue or highway reaching the map edge.
Road types
| Type | Width | Base capacity: vehicle movements per day | Main use |
|---|---|---|---|
| Street | 1 cell | About 8,000 | Local access, with one traffic lane each way and wide pavements |
| Road | 1 cell | About 18,400 | Two traffic lanes each way, with less pavement space |
| Avenue | 2 cells | About 64,800 | Three lanes in each direction, split into two carriageways |
| Street with Parking | 1 cell | About 7,360 | Local access with kerbside parking |
| Boulevard | 2 cells | About 38,400 | An avenue variant with parking and two lanes each way |
| Highway | 2 cells | About 86,400 | Three lanes each way for through traffic; does not provide building frontage |
Capacities describe a clear stretch across the road's full width, including both carriageways of an avenue, boulevard or highway. One vehicle passing once is one movement; its return is another. These are the simulation's daily capacity estimates, not a guaranteed number of journeys: junctions and highway merges reduce local capacity, and congestion slows traffic as demand builds up.
Open Roads and choose the type and variant, then drag its route. One-way variants take their direction from the drag. Check the direction before committing a one-way street; a route must work for the return journey too.
Highways and interchanges
Buildings cannot develop directly against a highway or its ramps. Provide ordinary streets for their frontage.
To connect a local road to a highway, run it head-on up to the highway and use Interchange at the road end. Leave room along the highway for entry and exit ramps. The tool reports when only one direction fits or the connection cannot be built.
Bridges and tunnels
Choose a bridge or tunnel variant for the road type. These are distinct from metro tunnels. The placement preview checks the crossing and approaches; start and end where the road can connect to the surface network.
Leave room for approaches and keep crossings connected at both ends. A bridge can concentrate much of the city's traffic, so consider where a second crossing or public transport would provide a useful alternative.
Junctions, traffic lights and roundabouts
Every crossing reduces how much traffic can pass. The control determines the share of the road's clear capacity available there, as well as the delay to drivers and people crossing on foot.
Daily figures are approximate vehicle movements through an ordinary Street crossing. Delay lists driving / walking, in seconds.
| Junction | Per day | Delay |
|---|---|---|
| Stop / yield | 5,200 | 12 / 6 |
| Mini-roundabout | 5,760 | 8 / 4 |
| Traffic lights | 7,200 | 28 / 30 |
| Roundabout | 7,600 | 6 / 3 |
The example uses an ordinary Street's 8,000 daily movements. Other road types use their own base capacity. A full roundabout has a single Street lane circulating around its island, so attaching a wider road does not give its ring that road's capacity. Delays are reference averages: crossings between different road sizes adjust the driving delay, and congestion adds further travel time. A roundabout also makes vehicles follow a longer path around the island.
- Stop / yield: costs nothing extra to install or operate. It is a simple choice for quiet streets, but has the lowest capacity and highest collision exposure of these controls.
- Mini-roundabout: a cheaper, compact upgrade for an existing two-way Street crossing, including Street with Parking. It improves capacity, delays and safety over stop / yield without reserving a larger site. It only joins streets, cannot serve one-way approaches or wider roads, and still carries less traffic than lights or a full roundabout.
- Traffic lights: move more traffic through an existing crossing and reduce collision exposure compared with stop / yield. They can serve wider-road junctions without a roundabout's 3×3 site. Drivers and pedestrians have the longest reference waits, and lights need more upkeep than either roundabout type.
- Roundabout: offers the highest entry-capacity share, shortest reference waits and lowest collision exposure. It needs a dry, level 3×3 site, costs more to build, and adds a detour around the island. Streets and Roads must meet the middle of a side head-on; avenues and highways cannot connect directly. Its single circulating lane can become the bottleneck when wider roads feed it.
A crossing uses one control at a time. Remove an existing roundabout before adding lights, or remove the lights before placing a roundabout. Choose for the traffic and space available rather than assuming one control suits every junction.
Junctions and walking
Give pedestrians continuous pavements and crossings between homes, shops, jobs and transit stops. The waits in the junction table count toward the walking time limit, so repeated crossings can put a nearby destination out of walking reach.
Use the pedestrian-network view and Foot traffic layer to check walking connections.
Road condition
Roads need ongoing maintenance, and busy roads cost more to keep in repair. Temporarily reducing the Roads budget can help balance the city budget, but wear builds up, slowing journeys and reducing access to jobs and services. Use the Road condition layer and click a road to check its condition before delays become serious.
At 100%, crews maintain the current condition. Funding above 100% gradually clears the repair backlog, so money saved by postponing maintenance will be needed later. Repairs take time; restoring funding does not instantly fix worn streets.
Arcade unlocks
Streets and roads are available at the start. Junction controls unlock at 10,000 residents. Avenues, highways, bridges, road tunnels and interchanges unlock at 50,000. Simulation has no population locks on these tools.
See Transport and parking for how routes become journeys, and Utilities before removing a connection to the map edge.