Why's "where" used after "system" instead of "which" or "that" even though "system" is not a place? I thought "where" can be used to describe a place.

Native speaker’s answer
Rebecca
In the informal context, "where" may be used instead of "which" or "that" for the same purpose. Ex: It is a level-two system which says that the driver has to be there. Ex: It is a level-two system that says that the driver has to be there.