Traffic on highways not behaving properly

Article verified: June 2019

Symptom

One or more of the following may occur:

• Vehicles aren't using all lanes on the highway
• I activated Enable highway-specific lane merging/splitting rules but nothing changed
• I made changes to my highway but vehicles are ignoring it
• Traffic jams due to merging at last node before a junction

Causes

Note:

For performance reasons, changes to highways do not update existing vehicles. Only vehicles spawned after the change will be aware of it.

The Customisations come in to effect immediately option in General settings does not apply to highways!

You have to wait for newly spawned vehicles to see the effect of changes. You can use Clear Traffic tool to remove old vehicles.

These symptoms are usually caused by incorrect mod settings, or not realising that highway traffic doesn't update until new vehicles spawn.

Solution

If traffic is not using all lanes:

• Enable Advanced AI in Gameplay settings - this makes all traffic use more lanes
• You can then use Dynamic lane selection (DLS) in Gameplay settings for even more lane changes

When using DLS, you might see traffic jams caused by vehicles all trying to use the middle lane just before junctions:

• Alter the DLS slider to under 50% (values of 30%-40% seem to work well on most cities)
• We are working on improving DLS to avoid this issue (see #263)

If traffic is not behaving properly at highway junctions:

• Enable highway-specific lane merging/splitting rules in Policies settings

Fixed?

If not, please let us know: Report a Bug

Other problems? See: Troubleshooting