À quoi bon l'économie ? De l'économie à la politique : l'exemple des transports

Economics is the only discipline, among the social sciences at least, which tries to be both descriptive and normative. In fact, however, as it is often difficult to find corroboration from empirical observations, economics tends to fall back on a theoretical approach; economic recommendations are rarely robust or consensual, and ultimately have little impact on decision-making.
To counter such criticisms, Quinet and Walliser focus on the field of transport, which is a special area of study within economics. They discuss three examples:
– transport of goods, which has been relatively well studied by economists, but their recommendations have tended to be blocked by vested interests, clinging to the status quo, even though the existing situation may be contrary to the collective interest as well as to their own interests in the long term;
– management of urban transport infrastructures, where -once again- “expert” opinion comes up against the inertia of institutions that fight to retain their position and defend their privileges;
– control of urban traffic flows, a particularly delicate matter, where opinions are divided and recommendations, once again, are thwarted by the lack of a common stance, with everyone concerned acting in accordance with their own particular logic.
As transport economists, are Émile Quinet and Bernard Walliser simply disappointed that their advice is not followed? No, they start by taking a critical look at their own field. “The models cannot cope with the diversity of the real world: every situation is unusual, there is no such thing as an average user, a representative firm or a standard cost.” The measures proposed are “too blind and clumsy, and fail to reach their targets”. Transport economists do not, above all, take sufficient account of the way the actors operate.
The authors conclude with some suggestions for ways in which economics might make progress. But they harbour no illusions: economists recommend change. For this to occur, their recommendations must chime with what the decision-makers want, something that the economists cannot determine…