This master thesis investigates how urban structures influence travel behaviour in the city region of Oslo and Akershus. Global climate change is one of the greatest challenges of our time. In search for ways to mitigate CO2 emissions, policymakers have turned their eyes to the transport sector. It is often conceived that polycentric city regions with compact, transit-oriented cities and neighbourhoods reduce distances travelled, discourage car use and promote the use of alternative transport modes. Multivariate quantitative models are applied in this thesis to address specifically three shortcomings in the assumed causality between urban structures and travel behaviour. First, car ownership usually overshadows the effect of all other factors on travel behaviour. The findings in this thesis indicate, however, that car ownership function as a mediator between urban structures and travel behaviour. Second, the influence of trip destination locations on travel behaviour is understudied, particularly in a Nordic context. In this thesis, the urban structures at trip destination locations, especially workplace density, turn out to have a major impact on transport mode choice. Third, few Nordic studies, and none of them Norwegian, have taken into account the street design in the local neighbourhoods. Moreover, diversity measures, such as the degree of mixed building or land use, have not been popular in Nordic studies. The findings in this thesis indicate that future studies should take diversity and design elements into consideration.