Cities: Skylines (Steam) - can't select a specific bus for my bus lines

[TinyWiking]

That means you've got broken mods. One or more of your mods is interfering and starting the game with no mods should solve this.

1. Right click Cities in your Steam library
2. Select Properties
3. Click Set Launch Options
4. Paste in the following: --disableMods --noWorkshop
5. Click OK
6. Restart Steam
7. Launch the game