Caltrans district 12 encompasses the entirety of Orange County. It operates and maintains field devices in Orange County. Located in Irvine, the TMC is shared with CHP.
| Caltrans |
| Caltrans Regional TMCs |
| PeMS |
| Roadway/Railroad Inspection Facilities |
| Caltrans TMC Roadside Equipment |
| Video Surveillance Clearing House |
| Excise Summary Terminal Activity Reporting System (ExSTARS) |