In modern societies spatial mobility of persons and goods has gained an undeniable importance. It also is one of the human activities with the highest effects on the environment and the most important single factor of anthropogenic climate change. The emissions caused by traffic also affect human health and buildings and ecosystems get badly damaged. Reducing negative traffic impacts is a difficult political task as well as a tremendous social challenge.

Different economic analyses give a rough idea of the extent of economic costs as due to traffic which ensue for the population of Switzerland. Recent studies assert annual costs of about 5 billions CHF a year caused by terrestrial traffic on road and rail alone. The most important fields regard health costs caused by airborne emissions and noise, by accident and damages on buildings and ecosystems. This account however does not include either the consequences of putative climate changes or infrastructure costs. In fact all these costs are not covered by those who caused them and they are therefore called external costs. For years welfare economists have been pleading for the application of the "polluter pays principle" of internalisation of external costs, in order to reduce traffic volume and environmental impact on a socially optimal level.

The promoting of efficient and alternative engines is a further option for the reduction of environmental impact caused by traffic. These measures have a considerable reducing potential with respect to negative traffic impacts, because they do not interfere with habits and mobility patterns. In mid 1995 a pilot and demonstration project (VEL1) was started in Mendrisio (a town in the Canton of Ticino). The scope of this project was to promote and test electrical light vehicles in everyday traffic conditions. In 2001 this project was expanded in two directions; hence including efficient vehicles with less than 120g of CO2-emissions per kilometre as well as being extended over the whole region of the Canton Tessin (VEL2).

Several technical, social and mobility-related aspects of this programme have been investigated in detail, so far. The present study is focused on the external costs of motorised individual mobility and the possibilities of reducing them by efficient vehicles, electric vehicles and electric scooters.