Device and method for preventing driving under influence

A method of preventing driving under influence, the method comprising:

• performing, by a processor, a first check of checking a presence or an absence of alcohol in indoor air of a vehicle before a driver boards the vehicle;
• performing, by the processor, a second check of checking the presence or the absence of the alcohol in the indoor air after the driver boards the vehicle;
• determining, by the processor, whether there is a possibility that the driver is drunken according to results of performing the first check and the second check;
• performing, by the processor, a blood alcohol level measurement of the driver upon determining that there is the possibility that the driver is drunken;
• and
• restricting, by the processor, start of the vehicle according to a result of the blood alcohol level measurement.