Habit and Latent Constructs in Bicycle Demand Modelling: a combined structural equation-ordinal logit model
CPD-3.29, 3/F The Jockey Club Tower, Centennial Campus, The University of Hong Kong
Juan de Dios Ortúzar
About the Speaker:
Juan de Dios Ortúzar got his PhD from Leeds University in 1980, became Full Professor at Pontificia Universidad Católica de Chile in 1986 and Emeritus in 2017. He received a Doctor Honoris Causa (Universidad de Cantabria, Spain) in 2018, the Life Achievement Award (International Association for Travel Behaviour Research) in 2012 and the Humboldt Research Award (Alexander von Humboldt Foundation) in 2010. Prof. Ortúzar pioneered the development of discrete choice modelling techniques and their application to determine willingness-to-pay for reducing externalities (accidents, noise and pollution). The valuation methodologies developed with his research team have been applied in Australia, Colombia, Germany, Norway and Spain.
He has formed several generations of professionals and specialists (including 15 PhD and 45 MSc) with a profound service vocation, who work in academia, government and professional practice in Chile, Latin America and Europe. He has published over 180 papers in archival journals and book chapters. Co-author of Modelling Transport, a book published by Wiley reflecting the state-of-practice in this discipline, which has sold over 20,000 copies and is now in its fourth edition. He also edited four international books and has two further books in Spanish dealing with travel demand models and econometrics of discrete choice. Co-author of Micro-GUTS, a simulation game to train transport planners, which is used by more than 50 academic institutions around the world. Finally, he is currently Co-Editor in Chief of Transportation Research A and member of the editorial board of several international journals.
In the last 21 years, bicycle use has experienced an enormous increase in Santiago, Chile. Data from the last three large-scale mobility surveys in the metropolis (1991, 2001-2006 and 2012) has revealed an impressive 13-time increase, from less than 0.3% to 1.87% and 4%, respectively, in this period. Notwithstanding, current figures are estimated to be higher and this research attempted to uncover the triggers for this increase in demand, and to examine in which form latent constructs, such as habit and risk aversion, influence the decision to travel by bike.
Two specially designed surveys were used. In the first, a random sample of 1432 individuals were asked about the main features of their daily trips to work or study, and whether they would be prepared to make that trip by bicycle; this question had the following responses available: No, Maybe/Depends and Yes. Non-bike users who selected one of the last two answers (812 individuals), were asked to participate in the second, a stated choice (SC) survey, with their current mode and bike as alternatives, considering the following level-of-service attributes: travel time, travel cost, walking and waiting time, type of bike infrastructure (cycleways and parking). In addition, respondents were requested to answer a set of specially designed psychometric indicators related with habit (current mode) and user perceptions (pro-environment; aversion to risk) towards bicycle use.
Data from the first survey was used to estimate a combined structural equation-ordinal logit model, where the utility function includes level-of-service attributes, socioeconomic characteristics, built environment attributes and three latent variables: habit, perception of insecurity when using a bike and a pro-environment (green) attitude. The model was applied to data from the 2012 mobility survey to estimate the proportion of individuals who could be willing to change to bike.
Data from the second survey will be used to estimate a mixed logit hybrid choice model including the above latent variables. We will also explore the possibility of estimating a joint model with both datasets.
Institute of Transport Studies, HKU
Department of Geography, HKU