Risk analysis of pedestrian and vehicle safety in windy environments

Prof. Chris Baker of the University of Birmingham, UK

It is a well-known and appreciated fact that high buildings can cause adverse wind conditions around their base, mainly through deflecting high speed winds at high levels down to ground level. The assessment of the wind environment around such buildings is a standard part of the planning approval process, and is now a fairly routine procedure. However, whilst wind comfort conditions are often assessed, it is not so usual to consider pedestrian safety in strong wind conditions around high rise buildings. When this is done, a variety of  criteria are used, but these seem to vary widely, and are largely based on wind tunnel tests on human stability, in flow conditions that were simply not in any way representative of those found around high rise buildings. Similarly no consideration is usually, if ever, give to the stability of cycles, motorcycles and other vehicles around high rise structures in strong winds, although there has been a body of work carried out in the past to look at high sided vehicle stability. The need for such effects to be considered has been tragically made clear in a recent incident in Leeds City Centre. The author will outline a methodology to address these issues which, while currently uncalibrated, holds some promise. The ultimate aim is to develop a detailed understanding of the behaviour of pedestrians and vehicles in highly turbulent and unsteady wind, and to apply this understanding to develop rational criteria that can be routinely used in the planning process.