Finding building shapes that minimize mean trip times

Abstract

The paper provides a computer-aided means of ensuring that a proposed multiple-floor building is shaped so that the time that people need to move around inside the building is minimized. The metric that captures this is the mean trip time. This is lower, for example, on a square floor than on an elongated floor of the same area. Spreadsheet formulae are provided to identify the number and shape of building floors that minimize mean trip time given building areas, people's walking speed, and lift speed and wait times. In the case of buildings with two floor sizes, the optimal number of floors of each size and the ratio of the two floor areas are also found. These formulae assume evenly distributed trips, i.e. that trip starts and finishes are equally and independently distributed throughout the building. This alleviates the need to obtain interdepartment-trip volumes and department areas. New simple distance theorems form the basis of the formulae. One odd finding is that, in some situations, a multiple-floor building with two floor sizes has a marginally lower mean trip time than a building of equal area in which all the floors are the same size. © 1992.