monde (1) puits (1) voyage (1) temps (durée) (1) statistiques (1) comportement (1) modèle (1) effet (1) science économique (1) demande (offre et demande) (1) Travel (1) Statistics (1) Voyages and travels (1) Travel (1) Time (1) Statistics (1) Respect (1) Motorcycles (1) Metropolitan areas (1) Local transit (1) Hire (1) Example (1) Evidence (1) Estimates (1) Economics (1) Cycles (1) Cities and towns (1) Change (1) Bicycles (1) Beginning (1)