Better than the calculation in constant francs, the idea of real-equivalent-work price makes it possible to explain that "people are driving as if gasoline had not gone up". In fact, at the beginning of 1981, in real value, gasoline was no more expensive that at the beginning of 1973. From 1970 to 1981, consumption of road vehicle fuels was constantly sensitive to variations in their price. The simultaneity of their respective movements is perfect. Price elasticity is considerably greater than what was found by earlier analyses. However, its interpretation would seem quite complex, making it illusory to try to establish a mechanical relationship between price and consumption. Until present, consumers were able to stay mobile thanks to a number of subterfuges. Because it seems that for them, the essential thing is to keep their independent mobility. When faced with expected price rises, few families accept the bringing into question of this mobility. More than an economic chattel, mobility has become a social value. Consequently, a policy designed to raise the real price of gasoline (or a genuine increase in its price) would have major economic and social implications.