large-scale net of wide roads that defines a series of cells or Superblocks, each containing a network of narrower streets.”Superblocks can also be retroactively superimposed on pre-existing grid plan by changing the traffic rules and streetscape of internal streets within the superblock, as in the case of Barcelona's superilles (Catalan for superblocks). Each superilla has nine city blocks, with speed limits on the internal roads slowed to 10–20 km/h, through traffic disallowed, and through travel possible only on the perimeter roads. In Soviet Union and post-Soviet states, a technical term out of construction industry is "residential massíve" (, Zhyloi massiv). According to the definition, a residential massíve consists of several of residential quarters (city blocks) that are associated by one architectural design (concept). In a number of cities in post-Soviet countries, several city neighborhoods have names like massiv or masyv and appeared in the second half of the 20th century with the rapid expansion of cities. In Central Europe, which was once in the Warsaw Pact, several cities have residential areas filled with inexpensive housing of multi-story buildings known as panelák (panel buildings). Panel buildings of similar architectural type may be erected as one residential city quarter or bigger residential area as massíve. History and usage Superblocks in North America, Brazil, the United Kingdom, and Australia Superblocks were popular during the early and mid-20th century auto-centric suburban development. They arose from modernist ideas in architecture and urban planning. Planning was then based upon the distance and speed scales for the automobile and discounted the pedestrian and cyclist modes, as obsolete transportation vehicles. A superblock is much larger than a traditional city block, with a greater setback for buildings, and is typically bounded by widely spaced, high-speed, arterial or circulating routes, rather than by local streets. Superblocks are often found in suburbs or planned cities or are the result of urban renewal of the mid-20th century in which a street hierarchy has replaced the traditional grid. In a residential area of a suburb, the interior of the superblock is typically served by dead-end or looped streets. The discontinuous streets served the automobile, as longer distances and the extra fuel required to go between destinations were not concerns, but at the pedestrian scale, the discontinuity of the roads added to the distance that must be traveled. The discontinuity inside the superblock forced automobile dependency, discouraged errand walking, and forced more traffic onto