the fewer continuous streets. That increased demand for through streets, which led ultimately to the streets having more travel lanes added for cars and made it more difficult for any pedestrian to cross such streets. In that way, superblocks cut up the city into isolated units, expanded automobile dominance, and made it impossible for pedestrians and cyclists to get anywhere outside of the superblock. Superblocks can also be found in central city areas, where they are more often associated with institutional, educational, recreational and corporate rather than residential uses. The urban planner Clarence Perry argued for use of superblocks and related ideas in his "neighborhood unit" plan, which aimed to organize space in a way that was more "pedestrian-friendly" and provided open plazas and other space for residents to socialize. Planners, today, now know that the street discontinuity and the multi-lane roads associated with superblocks have caused the decline of pedestrian and bicycle use everywhere with the "sprawl" pattern. The traditional urban block diffused automobile traffic onto several narrower roads at slower speeds. That more finely connected network of narrower roads better allowed the pedestrian and cyclist realms to flourish. The superblock, at the scale suitable only for automobiles, and not pedestrians, was the means for ultimate automobile dominance by the end of the 20th century. The same intention to facilitate pedestrian movement and socializing is captured by an influential 1989 conceptual design of a Pedestrian Pocket (see diagram). It is, similarly, a superblock composed of nine normal city blocks clustered around a light rail station and a central open space. Its circulation pattern consists primarily of a dense pedestrian network which is complementary to but independent from the car network. Access by car is provided by means of three loops. This superblock differs from Perry's concept in that it makes it impossible for cars to traverse it rather than very difficult; it is car-impermeable. In the 1930s, superblocks were often used in urban renewal public housing projects in American cities. In using superblocks, housing projects aimed to eliminate back alleys, which were often associated with slum conditions. During its construction in 1960, Brazil's administrative capital, Brasilia, employed a similar concept on the Asa Norte and Asa Sul of the Plano Piloto that is still in use. Each block is part of a group of four blocks called "Superquadras", sharing common recreation spaces such as parks, soccer fields and pools.