This report is the final report of the action COST 356 'EST - Towards the definition of a measurable environmentally sustainable transport'. It tries to answer the following questions: How can environmental impacts of transport be measured? How can measurements be transformed into operational indicators? How can several indicators
be jointly considered? And how can indicators be used in planning and decision making? Firstly we provide definition of 'indicator of environmental sustainability in
transport'. The functions, strengths and weaknesses of indicators as measurement tools, and as decision support tools are discussed. We define what "environmental
sustainability in transport" may mean through the transport system, the concepts of sustainable development and of environment. The concept of 'chain of causality'
between a source and a final target is developed, as a common reference for indicators and assessments. As the decision making context influences the perceived
and actual needs for indicators and methods, we also analysed the dimensions and context of decision making. We derived criteria and methods for the assessment and
selection of indicators of environmental sustainability in transport, in terms of measurement, monitoring and management. The methods and the criteria are
exemplified for seven chains of causality. Methods for a comprehensive joint consideration of environmentally sustainable indicators are analyzed and evaluated.
They concerned aggregated or composite indicators as well as multi-criteria methods. Five case studies are presented. Finally, recommendations for continued research and development of indicators and joint considerations methods for assessment of environmental sustainability in transport are given.