According to this invention, in 1st feature, in order to decide the future point in time when alcoholic density in the blood of the user is under threshold value, the operational possible system (10) is offered. The system (10), as detected the present alcoholic density in the blood of the user, operational possible alcoholic sensor expedient (12) with, the portable device (14) with it has. Alcoholic sensor expedient (12) and the portable device (14), each radio communication expedient (1612 and 1614) it has. Alcoholic sensor expedient (12) radio communication expedient inside (1612), in order present alcoholic density the portable device (14) radio communication expedient inside (1614) the radio to transmit, it is operation possible. In addition the portable device (14), radio communication expedient (1614) the control means which are connected (18) with, control means (18) each the clock expedient which is connected (20) and memory expedient (22) with it has. Control means (18), in order present alcoholic density and clock expedient (20) from the present time stamp memory expedient (22) to house, it is operation possible. In addition the portable device (14), control means (18) the calculation expedient which is connected (24) it has, calculation expedient (24), memory expedient (22) on the basis of the feature of the user which produces effect on known alcoholic burning rate or alcoholic burning rate of the user which is housed in order to calculate future point in time on the basis of the alcoholic burning rate which was calculated calculation expedient (24) by, it is operation possible.本発明によれば、第1の態様において、ユーザの血中のアルコール濃度がしきい値未満である将来の時点を決定するように動作可能なシステム(10)が提供される。システム(10)は、ユーザの血中の現在のアルコール濃度を検出するように動作可能なアルコール・センサ手段(12)と、ポータブル装置(14)とを備える。アルコール・センサ手段(12)およびポータブル装置(14)は、各々無線通信手段(1612、1614)を備える。アルコール・センサ手段(12)内の無線通信手段(1612)は、現在のアルコール濃度をポータブル装置(14)内の無線通信手段(1614)に無線伝送するように動作可能である。ポータブル装置(14)はまた、無線通信手段(1614)に接続されている制御手段(18)と、制御手段(18)に各々接続されているクロック手段(20)およびメモリ手段(22)とを備える。制御
