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Two doctorates for ‘traffic couple’ at the University of Twente

A married couple obtained separate doctorates at the University of Twente’s Faculty of Engineering Technology (ET) on the same day: Friday, 5 November 2021.

Both Marie-José Olde Kalter and Erwin Bezembinder have carried out part-time PhD research, independently of one another, as external PhD candidates, in the Transport Engineering and Management research group since 2013-2014. Marie-José Olde Kalter works at Goudappel (a traffic research consultancy) in Deventer. Erwin Bezembinder works as a lecturer on traffic-related topics at Saxion University of Applied Sciences, also in Deventer. They obtained their doctoral degrees on the same day.

It is a rare for married couples to earn the academic title of doctor on the same day, but this is the fifth time that this has happened at the University of Twente. A couple from South Korea achieved this in 2014, a couple from Pakistan and one from Iraq in 2016, and the first Dutch couple, in 2017.


More than half of the 17 billion movements that take place annually in the Netherlands are trips made by car and, until 2020, the number of car kilometres rose every year. Among other things, the increase in car traffic exacerbates congestion and CO2 emissions and has negative effects on the air quality and use of space in cities. To reduce these detrimental effects, we must promote sustainable mobility by encouraging the switch to bicycles and public transport, for example. To this end, we need insight into people’s motivation, the underlying reasons for why they change their behaviour (or not) and the obstacles to using different transport modes. Answers to the questions of why, when and in what way people opt for a different transport mode are essential. A better understanding of the factors that affect people’s choice of transport mode will help policymakers develop and implement effective policy measures that will achieve the desired behavioural changes.

The availability of longitudinal data offers new opportunities for studying the dynamics in the choice of transport mode. Two extensive panel surveys were used in this research: the Netherlands Mobility Panel (Mobiliteitspanel Nederland, MPN) and the National Movement Panel (Nationaal Verplaatsingspanel, NVP). The research results show that people are more likely to change their behaviour than their attitudes and preferences and that a change in attitudes and preferences often follows a behavioural change. The most important message for policymakers is therefore that they must primarily use experiments, pilot projects and measures that focus directly on the desired behavioural changes. Acceptance of measures can be encouraged if the desired behaviour is linked to positive experiences. Examples of policy measures that ‘elicit’ different behaviour are a free trial period with public transport, alterations to the physical living environment such as investments in pedestrian and cycling infrastructure to promote active mobility, or price policy, such as making people pay for using their car.  For further information: Doctoral thesis ‘Dynamics in mode choice behaviour.


Junctions are decisive factors in the handling of traffic in urban networks. The choice of a traffic control installation or roundabout can affect the flow of traffic, the number of accidents and/or the emission of hazardous substances both at the junction itself and/or other points in the network. Based on various optimisation models and cases used in this research, it can be concluded that the total loss time in urban networks can be reduced by 37% by opting for the right junction design. Targeting an operational optimum also leads to 6% fewer accidents and reduces emissions by 1%. A striking point is that this can almost all be realised simply by optimising the junction choice locally, that is, by opting for the junction design with the least loss time at each particular location. In the course of the research, tools were developed to optimise the choice of junction design, both locally and in urban networks, based on traffic flow, safety and air quality. For further information: Doctoral thesis ‘Junction design rules: improving junction design choices in urban traffic networks’.

drs. J.G.M. van den Elshout (Janneke)
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