You didn't think of it's exists...

...but it does.
User's manual for the subway system in Budapest.
It shows that which door (of the metro) is the closest to the exit in the signed stations.
(for example 2.4 means that the closest door to the exit is the 4th. door of the 2nd. wagon)
Please somebody to sign back to me, is it works truely? I would like to know.
Double "A" for the idea!