The GOFAR device tracks the speed of the car only, it does not monitor your speed against the limit on the road you are driving.
If you want it use it to help keep you below the speed limit, you can set the speed threshold of the device (iOS only) via the settings menu:
- press the settings symbol at the bottom right of the home screen
- select 'Ray Settings'
- adjust the speed threshold to the level where you want to receive a warning light