A 30 km/h zone, also known as a ‘zone 30’ or a ‘residential area’ is generally situated in an urban area and consists of connected access roads with a 30 km/h speed limit. In the Sustainable Safety vision (see also SWOV Fact sheet Sustainably Road Safety) 30 km/h zones have a residential function, for example for living or shopping. In addition, there are also isolated 30 km/h roads that provide access to ‘erfs’, urban yards with houses, shops, offices et cetera. Generally, through-traffic is not welcome in 30 km/h zones; car traffic without its origin or destination in that zone must be banned.
According to the Sustainable Safety requirements residential areas must be ‘as large as possible’. The size of a residential area is dependent on the structure and density of a road network which are often determined by the geographical features. In addition, criteria for road safety, quality of life and accessibility determine the size of residential areas. In fact, there are large variations in the size of 30 km/h zones areas.