| Word | Description |
| Failsafe | As in output relay design, a type of output-relay design that produces a constant call, thereby keeping traffic moving, in the event that the detector unit fails. |
| Farad | A unit of capacitance, usually expressed in microfarads (uF), on millionth of a farad. |
| Feeder Cable | See Lead-In Cable. |
| FHWA | Federal Highway Administration |
| Field | For more information on our Centurion Field software, or to download a current copy Click Here. |
| Field of Influence | See Zone of Detection. |
| Freeway Surveillance | Process or method of monitoring freeway traffic performance and control system operation. |
| Frequency | The number of times an alternating current repeats its cycle in 1 second. |
| Full-Traffic-Actuated Controller | A type of traffic actuated controller assembly in which means are provided for traffic actuation on all approaches to the intersection (NEMA). See Also: Traffic-Actuated Controller Assembly, Semi-Traffic-Actuated Controller, and/or Pedestrian-Actuated Controller Assembly |
| Full-Traffic-Acuated Controller Assembly | A type of traffic-actuated controller assembly in which means are provided for traffic actuation on all approaches to the intersection. |