Sien (°1994) has worked at the Department of Geography since August 2019. She investigates cycling safety of adolescents. In her PhD she studies how the physical environment influences adolescents’ choice for cycling routes when going to school. Besides that, she uses the Qualitative Trajectory Calculus (QTC) to analyse interactions between road users at intersections. In this way, intersections and roads can be made more pro-cycling. Furthermore, she is involved in the citizen science project ‘Een fiets-STEM voor scholen’ in which pupils in secondary schools analyse the cycling safety in the neighbourhood of their school based on a bicycle barometer.