Two major demographic changes are affecting many countries. First identified was the graying of the population, more correctly, the growing proportion of the population having an advanced age, say 65 years. Second is the relatively recently recognized set of changes sometimes characterized (incompletely) as the obesity epidemic which is affecting all ages. The second demographic change has primary characteristics such as increased body mass, increased size (especially girth), and decreased physical fitness. Secondary characteristics are various health effects, some of which were formerly more associated with aging; these include hypertension, type 2 diabetes, joint deterioration, and some mental performance changes as well as movement performance changes including reduced walking speed and endurance. These changes could, in turn, affect walking-related fall and injury propensity plus the ability to cope with the physical demands of sustained crowd movement, for example, associated with evacuation of major facilities including high-occupancy buildings such as sports venues and high-rise structures. The time, as well as necessary organizational preparedness, required to accomplish such relatively demanding crowd movement will increase with these demographic changes. In terms of needed design improvements, consideration must now be given to increasing sidewalk and passageway widthespecially stairwaysto accommodate enlarged lateral dimensions of people as well as increased lateral sway behavior exacerbated with relatively slow movement speeds. Consideration must also be given to improving the usability of stairs, including lower step height, and increased provision of rest areas which, for high-rise building evacuations, might dictate increased stair landing sizes.
Abstract