In a time where governments have limited budgets for infrastructure expansion and have to rely more on managing travel demand, it is of crucial importance to understand preferences, choices and attitudes of travellers and citizens. This however is complex in the sense that it is influenced by many factors that mutually influence each other. To unravel this complexity, I develop and apply in my research sophisticated multivariate analysis and advanced data collection techniques. I aim to keep up with promising new approaches and try to be among the first to apply them on representative samples. In this way I contribute to the further development of these methods and generate policy relevant behavioural insights along the way.
My research is mainly based on data collected by large scale survey methods. In particular, I have specialized in developing advanced stated choice experiments, a data collection method that allows studying the trade-offs individuals make while making choices. Among others, I have contributed to: (i) the development of methods to include many more decision attributes than standard experiments allow, (ii) ways to study the impact of decision contexts on choices and (iii) ways to study group decision making. In addition, I developed methods to identify personal networks and have ample of experience with measuring latent variables, such as perceptions and attitudes. With respect to data-analysis, I apply a wide range of multivariate data-analysis techniques, among others: (i) discrete choice models to estimate the weights of the decision attributes; (ii) multiple regression analysis and structural equation models to study the relative importance of explanatory variables and to disentangle complex causal relationships; and (iii) latent class models that enable to segment the population in different classes that have homogeneous preferences.
Topics of research
Content wise my research can be grouped into two broad categories: mode choice and innovative transport technology. With respect to mode choice, I mainly worked on modelling multi-modal choices. I have conducted a range of stated choice experiments and estimated models for travel choices in which connections between different modes of transport and making transfers play a role. The estimated models, among others, have been incorporated in a novel Supernetwork model by change in transport choices can be predicted of integrated transport and land use scenario’s. My research on innovative transport technology mainly involves measuring and modelling consumer preferences for, and citizen acceptance of: (i) alternative fuelled vehicles (hydrogen, electric) and refuelling stations, (ii) travel information services, and (iii) automated driving.
Currently I am developing a research program in which the various streams of my research come together. The focus will be on activities while traveling, both in public transport and in automated driving, and its impact on mode choice and value of time. Initial thoughts are, among others, to study: (i) interdependencies between activities (including time fragmentation), ICT use, mode choice (e.g. train, new car, automated vehicle), and residential choice; and (ii) group decision making, such as household decisions on purchase and use of cars and the impact of the personal network on individual decisions. In this program, I aim to incorporate insights from various disciplines, such as transport, social geography, psychology and sociology. In addition, several methodological challenges in the research on new technology remain having my attention, among others: (i) the selection of respondents and generalizability issues, (ii) the measurement of opinions of technology that people have not yet experienced, (iii) the change of preferences as technology matures and societal conditions change.