A procedure was developed for quantifying the pavement cost of proposed changes in regulations governing truck weights and dimensions, particularly the marginal cost method used for pavement cost allocation. The procedure was part of a comprehensive study undertaken by the Ontario Ministry of Transportation in response to government and industry initiatives to harmonize Ontario’s truck regulations with those in surrounding jurisdictions. The marginal pavement cost of truck damage was defined as a unit cost of providing pavement structure for one additional passage of a unit truckload (expressed as equivalent single axle load). The results indicate that the highway type (or truck volumes associated with the highway type) has a major influence on marginal costs. For example, the annualized pavement life-cycle cost of the passage of one additional typical truck on 1 km of a highway in southern Ontario can range from about $0.004 for a freeway to $0.46 for a local road (Canadian dollars). The marginal cost method can be used to quantify pavement damage due to any axle load combination for both new and existing, in-service pavements. The knowledge of marginal costs would enable highway agencies to quantify the impact of specific regulatory changes of truck axle weights on pavement costs; for example, to quantify the pavement costs associated with increasing allowable truck weights of logging trucks on a specific segment of the highway network.