Passengers using elevators would stay at an elevator lobby of the 1st. floor, when the concentration percentage of passengers exceed the transportation capacity of the elevators. If staying population can be estimated, it is effective in planning of elevator lobby space. This paper presents the relation between the staying population and the transportation capacity, which could be found out from the fact that staying population depends on the only two factors (transportationcapacity and arrival distribution of passengers). By using this relation, one can be easily estimate the staying population.
