This project focuses on the optimization of the safety and attractiveness of streets, and aims to promote walking and cycling among neighbourhood residents. To achieve this aim, this project will use a participatory research design. Neighbourhood residents will provide information about which specific environmental characteristics contribute to the safety and attractiveness of streets. This will be done while walking (on a treadmill) or cycling (on a bicycle ergometer) through a virtual simulation of their neighbourhood. In this project, two studies will be conducted: an exploratory study and an experimental study. Both studies will be conducted for each behaviour (walking and cycling). The first exploratory study will examine how individuals from different age groups (children, adolescents, (older) adults) experience the authenticity of three-dimensional virtual manipulations. Furthermore, these individuals will give suggestions regarding potential environmental manipulations that could increase the perceived safety and attractiveness to walk or cycle, and these manipulations will be tested on their authenticity. The second experimental study will examine which environmental manipulations are needed to create environments that are safe and attractive to walk and cycle. This will be studied using quantitative and qualitative methods. This study will be conducted in collaboration with the city of Ghent, and will take place in a specific neighbourhood in Ghent, where street renovations are planned in the coming years. Participants are neighbourhood residents and will be asked to adjust their own street on the computer. This will be done using an interactive tool where individuals can build and adjust a street using different street characteristics (e.g. adding a tree or a cycling lane). Using this method stimulates participation of inhabitants in the re-design of streets. Once participants created their ‘most safe’ and ‘most attractive’ street, they will have the opportunity to virtually cycle or walk through this street and to give feedback. By compiling the data of participants in different age groups and results on walking and cycling, a most optimal street design can be proposed. This information will be communicated to the instances who are responsible for redesigning the neighbourhood.