This paper systematically reviews two questions central for environmental impact assessment: What are the relevant environmental impacts of transport? And, are they improving, i.e. what is their overall assessment? We focus on a European approach as illustrated by the ‘Transport and Environment Report-ing Mechanism (TERM)’ of the European Environment Agency. Although this system is in practical operation since 1999, a systematic review of the TERM indicators still identifies numerous points for improvement: Redundant, non-pertinent and non-representative indicators can be eliminated and reduces data demand by a factor of three. Overview can be improved by a classification according to environmental impact categories. These criteria allow to streamline the current twenty-four indicators to a maximum number of seven key indicators.