Tribune. The debate rages between supporters of the 30 km / h limit in the city and those who want to keep the speed in the car. For the former, it is a necessary condition for the fight against the car, source of pollution, noise and greenhouse gas emissions; for the others, it is a question of maintaining access to the city. The city is the place of opportunities and makes it possible to increase the density of exchanges on a restricted territory with a significant supply of culture, goods and services, and jobs.
This agglomeration effect has one drawback, however: congestion. Speed has historically made it possible to de-densify the city with notable advantages: a better distribution of jobs (Paris has thus lost two hundred thousand jobs in fifty years which have relocated to the outskirts), improved housing conditions with larger housing and cheaper, easier access to the city.
If the scarce resource for the inhabitants of the rich countries that we are is time, for a city, it is the public space
While in 1900 we were traveling 4 km / d, today we are at 40 km / d with still one hour of daily travel, i.e. a tenfold increase in travel speed. This revolution is the result of a tenfold increase in gross domestic product (GDP) per capita and technical progress, slow modes having been supplanted by fast modes, the general increase in income having allowed us to increase our programs. activities through democratization of speed.
Today, in an era of abundance, the scarce resource is time and this is what explains this appetite for speed. Speed has allowed urban sprawl, hated by supporters of the city of the quarter hour: this debate on the configuration of the city is the same as that on speed. The city has thus always been the place of the search for a balance between the disadvantages of speed and those of density.
However, for twenty years, the distances traveled per inhabitant each day have not increased: the speed has reached a ceiling. It is therefore no coincidence that a project like Hyperloop – transport at 1000 km / h in an evacuated tube – appears in this context: for its promoters it is a question of crossing a new threshold and improving the mobility by reducing travel times. However Hyperloop, not to mention the exorbitant cost of this solution, is doomed to failure because it neglects the essential need of a city: the speed, that is to say the number of people transported per hour.
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