Nowadays we are rightly more aware of environmental preoccupations, and naturally this is also the case for the consequences and impacts of Transport. The matter is to have at one’s disposal some adequate tools of evaluation and information about the resulting impacts. In general such tools and indicators do exist, but sometimes one may feel today that these indicators are very numerous, and at the same time that they are disparate, inhomogeneous and respectively ignorant of each other from one environmental profession to another. Firstly, it is thus necessary to step back, to clear up the set of existing indicators and to propose a more structured and coordinated approach in order to attain more suitable impact tools. Next, the text focuses on the “impact law” step, say the relation between an objective input variable describing exposure to pollution and an adapted new impact variable having to characterize the consequences of transportation on environment in “ad-hoc” units (say the related end-points responses). This step is essential, many users and professions have requested “a major effort” for it, and it is again useful to step back. We note that there is a strong connexion between the impact variable status and the associated impact law. The text intends to make an inventory of different methods used to do this, and then to classify and comment on them. Some other developments are also proposed, new or extracted from the vast mathematical arsenal, as parts of suitable impact laws for less considered pollutions than noise and air pollution, such as visual impact in landscapes and rural space fragmentation by new infrastructures.