This paper compares estimates of the value of time for various theoretical models, using the same database and the same econometric methods for all the estimates. The results exhibit an important variability. Even if theoretical reasons or bad econometric quality makes some of these models irrelevant, one may suspect currently available estimates not to be robust. New models in the future may imply new estimates, very different form the current ones. The results also show the importance of a good knowledge of supply attributes and of the agent characteristics.
As regard the transport by road either of goods or of people, the necessity of fulfilling the trip in process and the related habit of working long hours have forever brought about the setting up of dispensatory rules concerning working hours. Admittedly, the MP’s do accept today that the law may evolve by issuing decrees as well as signing dispensatory collective agreements to a certain extent. But the pressure of management and labour unions is so severe that neither the rules which have been discussed with the relevant administration nor the collective agreements don’t precisely correspond with the frame of the law. Therefore, for many years, the Court has considered a great deal of legal measures as illegal. The state, whose aim is to maintain social peace and public order but which takes part to preoperative discussions may impose these exorbitant rules by various means, especially by using its right to pass laws as well as its ability to take advantage of various loopholes or assets of the Justice Administration.
In order to assess the social cost of aircraft noise at Orly Airport, we chose a stated preference method: the Contingent Valuation Method (CVM). Despite the bias involved, the use of CVM also made possible to deepen the noise perception of the 607 people surveyed, and in particular to highlight their level of noise annoyance, hence to measure the annoyance influence on willingness to pay (WTP), conventional standard to evaluate the social cost. With this intention, two complementary statistical processing runs have been carried out: the first deals with the annoyance and the factors which explain it, the second one focus on WTP and its variables. One of the most important results is that annoyance of Orly airport neighbourhoods represents the main variable of the stated preferences for a quieter environment. The social cost amounts deduced from the WTP declared are then presented. The document ends with considerations on their operational uses in a European policy context marked by emergent debate on social acceptability of airports.