There is need for better understanding of how mobility management interventions work and how they affect the individuals' modal choice decisions, as well as need for robust evaluation techniques allowing any behavioural changes to be observed. Changing individual's behaviour is not a one-step process and any evaluation methodology should account for this. A new standardized expert evaluation resource MaxSUMO takes this step-wise process into account. MaxSUMO is based on a new theoretical behavioural change model MaxSEM which measures individuals' stage positions (their susceptibility to change behaviour) and stage movement (progression towards actual behavioural change). This paper illustrates the use of MaxSUMO by the evaluation of the mobility campaign "I keep moving, even without my car" undertaken by the City of Ghent.