with the circuitry 6 and or corresponding programming and a connection 7 to the electrical electronic system 8 of the vehicle by means of which its speed is displayed in order to prevent the device from triggering when the vehicle stops likewise if the vehicle 39 s electrical electronic installations allow it an additional connection 9 may be fitted so that the control unit simultaneously or regardless of the operating of the acoustic warning triggers a drop in speed and causes the vehicle to stop if driver drowsiness is detected since the speed is also displayed the device may also optionally be programmed to be triggered in the case where it detects speed above a programmed maximum the system is fitted with a switch 10 to turn it off as well as selector switches 11 by means of which the user may select the operating mode triggering of the acoustic warning stopping of the vehicle or both simultaneously as well as if the intention is for the device to trigger only in case of drowsiness or also in case of exceeding the maximum speed optionally as seen in fig2 the invention comprises a variation for vehicles not fitted out to display speed because of the electrical electronic installations themselves in this case the control unit may be set to ignore registering the speed of the vehicle which would cause the acoustic warning to trigger on removing the hands from the steering wheel or detecting a drop in.