Using a large set of data, including age, pavement type, traffic etc., on sections of the road network, this paper sets out to assess the marginal cost of using the road infrastructure. It suggests a strategy for identifying major differences in marginal costs across the road network, and provides evidence that not only heavy vehicles but also cars contribute to road quality deterioration. The hypothesis is that this is due to the widespread use of studded tires in countries with regular freeze-thaw cycles. No indication of deterioration due to time per se is found.