Marchetti's constant is a term for the average amount of time spent commuting each day, which is approximately one hour. Developed by Venetian physicist Cesare Marchetti, it posits that although forms of urban planning and transport may change, and although some live in villages and others in cities, people gradually adjust their lives to their conditions (including location of their homes relative to their workplace) such that the average travel time stays approximately constant. Even since Neolithic times, people have kept the time at which they travel per day the same, even though the distance may increase.