In an environment in which Public Transport plays an ever growing role in urban areas and passenger experience. In-depth knowledge on customer satisfaction is key in improving passenger experience. Crowding has shown to be an important aspect of route and mode choice, but its impact on customer satisfaction has not yet been quantitatively explored. This paper investigates this impact. Using a Structural Equation Model based on customer satisfaction survey data and corresponding occupancy and punctuality numbers a significant effect of occupancy levels on perceived crowding was found. In-vehicle crowding, both subjective and objective, seems to impact overall customer satisfaction indirect, with comfort being the main mediating variable. Model results were converted into a calculation tool which can be used to assess the impact of changes in passenger numbers, passenger distribution and frequencies on customer satisfaction. Further research can verify the linearity of the relation between in-vehicle crowding and customer satisfaction and deepen knowledge of external factors such as weather and disruptions have on experienced crowding.