It's also used as a lock/ keyless entry.. as well as to control drunk driving in USA.
This is a code entry. Basically if you set this code and one get drunk.. The car will not open until a correct code is entered. It's not a perfect solution as few drunk or under influence of some stuff still able to remember the code and still drive drunk.. Though its still a good deterrence system.. Again the driver has to activate it before getting drunk.. 
Accord bhae please correct me if I m wrong please...