Reduction of the environmental impact of freight transport becomes more crucial as the worldwide volume of freight transport increases. Not only technological improvements are needed but also organizational and operational changes designed to optimize logistic chains, including the allocation of goods to transport modes. Such changes often imply an increase in transport prices and are therefore realistic only if an explicit demand of shippers for environmental improvements can be observed. A shipper survey was administered in Switzerland to evaluate relevant factors in shipper demand for land transport services (including the role of freight transport's environmental performance). The survey included stated-choice experiments based on real-world transport chains. A set of logit models was estimated to quantify shippers' willingness to pay for reducing the environmental impact of their shipments. Special focus was given to differences between types of commodities shipped and to the impact on choice behavior of conventional quality aspects (on-time reliability, transit time, etc.). Results support the hypothesis that the closer a shipper is linked to the end consumer, the higher the sensitivity to environmental concerns.