The intensive and increasing use of the car, and its consequences in terms of air pollution, noise and overcrowding of the physical space of the cities, are one of the environmental problems that most affect contemporary societies.

As the national surveys conducted by OBSERVA show in 1997 and 2000, this and other environmental issues are already part of the concerns of the Portuguese population, which places the environment among the main problems facing it. More specifically, the Portuguese generally recognize traffic, noise and air pollution as evils that have worsened over the years in urban areas and point to the intensity and density of road traffic as one of the most unpleasant aspects of their areas of residence, in particular.

If this sensitivity manifests itself unequivocally in the level of evaluations and values, it has only partly translated into everyday practices. Although it is recognized collectively that the intensive use of the car has negative environmental consequences, such recognition has not brought significant changes in the individual practices regarding the use of the private automobile in the day to day. Although some respondents say, for example, that they avoid using their car during their daily commute, other indicators point to a built-in resistance to the possibility of replacing or supplementing individual transport by public transport or other related environmental safeguards with the car.

It can not be ignored, however, that social attitudes more or less open to change in environmental culture are not independent of the circumstances and conditions surrounding the problem of urban mobility and the reduction of the massive use of cars within cities. In Portugal it is known that these conditions and circumstances are not the most favorable, especially in relation to public transport systems, which are insufficient in
covered mesh, frequency, punctuality or convenience.

It is in this context that the initiative for the promotion by public authorities of days without cars in the cities is inscribed. After national experiences in France in 1998, widespread editing throughout the European Union space and to other countries, inside and outside Europe. In Portugal, six cities (Aveiro, Beja, Évora, Leiria, Lisboa and Porto) and one village (Sintra) participated in this initiative.

This time, the very fact that the officially adhering localities are 51, including the largest cities and covering practically the entire national territory, from north to south and from the coast to the interior, and also the autonomous regions, an element of positive evaluation of the 2001 version of the European Day without Cars (DESC).

According to the methodological strategy established by the team responsible for this study and presented to IPAMB, the empirical collection for the social impact assessment of ESCR was based on an integrated set of quantitative and qualitative techniques, whose registration tools were delivered to the Institute , in its own volume, as soon as its elaboration has been completed.

They were a questionnaire survey at national level (Mainland and Autonomous Regions) of 1,200 applications, carried out by telephone in the days immediately following the event; a direct, systematic and comparative observation of the terrain through various pre-built recording instruments and photographs, the behavior and occurrences inside and outside the areas without traffic in four selected cities, namely Lisbon, Porto, Coimbra and Bragança; interviews with the heads of the ESCB participating authorities on the preparation, implementation and outcome of the initiative; collection and analysis of reference press, daily and weekly, as regards news coverage per se, but also to the opinion expressly produced. Each of these techniques individually considered and the integrated and cross-readings they allow, when taken together, have provided a very wide mass of empirical information relevant for evaluative purposes. In any case, it would still be worth having a fifth line of information collection in future ESCR assessments, which this time could not be put into practice. It would be a question of extending the survey done to the residents in the participating cities to those who live outside these cities, but who enter and leave them daily for professional, school or other reasons. This enlargement would be particularly important, of course, in the case of Lisbon and Porto.