The evaluation of navigation projects has evolved from a standard procedure done strictly by engineers and economists to a process that involves a wide range of stakeholders. Not surprisingly, these diverse stakeholders have different views regarding what should count in the benefit–cost analysis of water resource development projects and how the effects are to be economically valued. The methodologies that are described have been used to measure and monetize some of the externalities of inland navigation, the benefits and costs of which have not traditionally been included in benefit–cost ratios. The emphasis is the benefits (lower air emissions) associated with freight transport via water compared with those of other modes, particularly truck.