Environmental sustainability is a requirement for modern urban freight transport systems. On a global scale, most resources are currently consumed in cities, contributing to the economic importance of urban freight transport as well as its poor environmental performance. However, there is a lack of knowledge about how to correctly quantify the environmental efficiency of urban freight systems. In this context, this paper proposes a new methodology for evaluating the environmental performance of urban freight transport systems by applying the Overall Greenness Performance (OGP) tool. OGP is a lean-based hierarchy of metrics that uses the value-added concept to relate a company¿s productivity with its environmental performance. The proposed methodology uses a mixed-integer linear programming model to assess the environmental impact of the activities and/or requirements in an urban freight transportation system. This paper examines how company context, the supply chain and value stream activity types, namely value adding, necessary but non-value adding and non-value adding, affect a system¿s performance, operational costs and environmental impact. Real data from the city of Bogotá, Colombia, were used to validate this approach. A sensitivity analysis was performed with different companies, demands and costs in order to evaluate the trade-offs between economic performance and environmental impact.