The introduction of urban transit systems in the mid 19th century permitted the first forms of separation between the places of work and residence. By the middle of the nineteenth century, households with higher incomes relocated to relatively rural locations and commuted by rail into the city center. The “commutation” of fares to lower prices when purchasing tickets in monthly quantities introduced the term “commuter” to the English vocabulary.
During the second half of the nineteenth century, public transport improvements fundamentally changed accessibility, which in turn extended the diameter of the city and changed the shape of cities from a more-or-less circular structure to a star-shaped structure. Trackside suburbs developed at railway stations that were located up to 30 km away from the city center, and linear strips of medium-density, mixed land use occurred along electric streetcar routes, creating in essence the first commercial strips.