| 摘要 |
The control unit is fed by the vehicle battery and takes intake from an existing speed sensor or an add-on unit e.g. in the speedometer drive cable. Speed limits imposed with statutory force for different road conditions, e.g. urban, rural or motorway, are keyed in by the driver, the last to be keyed indicated on a digital panel. A yellow light is used to confirm actual speed lies within limits of tolerance of any specified speed. Green indicates the speed is at the lower limit and red that it is at the higher. Green and red are arranged to blink when the speed is beyond these limits; these are reinforced by an audible signal when the departure from the limit is extreme. Optionally, on de luxe models, the speed is announced by a voice synthesizer. |
