Shopping Centre Traffic Impact: A Traffic Forecasting Model for Medium Sized Towns in Italy

This paper reports the results of a research project conducted to predict retail demand and evaluate its impact on the transportation system. Similar studies found in the "Guidelines for Traffic Impact Assessment" (edited by IHT), the Planning Policy Guidelines (PPG 6 and PPG 13) published in Great Britain, and the TRIP GENERATION manual edited by ITE in the United States of America evaluate the number of consumers attracted based on retail size. Our approach differs in that we evaluate consumer behaviour at shop destination by means of questionnaires then apply statistical methods such as multiple correspondence and cluster analysis to define trip generation and retail choice behavioural characteristics and rank consumers accordingly; we then apply variables to the different rankings and build algorithms based only on shop characteristics (size, location, accessibility, ect.) which are then calibrated by multiple regression to define the relationship between the estimated number of consumers and real consumer flow. Questionnaires were collected at six large shopping malls in the metropolitan areas of Cagliari and Sassari. Further studies are also being conducted along the same line in another 14 urban areas in Italy, where we are investigating different size shops (hypermarkets, supermarkets, corner shops).