Daytime Population Tracking for Planning and Pollution Exposure Assessment

Abstract

Knowing more precisely where people are across the day and when they are there is fundamental information for many fields including transportation planning, environmental impact analysis, marketing and emergency evacuation. In this paper, we adapt a methodology originally proposed by Roddis and Richardson (1998) for tracking populations across the day using large household travel survey databases. Using five-year pooled data from the Sydney HTS, we effectively take population ‘snapshots’ of the city every 5 minutes, and locate the population using the origin-destination, time and weighting information from the survey sample. We then apply the approach to two different case studies, namely 1) emergency evacuation in the Sydney CBD, and 2) environmental exposure to noise pollution. Through the case studies we demonstrate the various strengths of the approach as well as the caveats, which primarily relate to sample size issues for small-area applications, our ability to rely on people to accurately record where they go, and the frequent need to examine weekday and weekend populations separately. In the case of environmental exposure, we need to understand the production and dispersion behavior of the various pollutant types, if we wish to understand a ‘dynamic’ population exposure to each of these pollutants more precisely.