Social severance is the general term applied to the negative effects that roads and their traffic have on social interaction. In particular it relates to the imposition of barriers that deter people's movements. This social severance has been identified as an important impact that requires consideration as part of the assessment of major roading schemes. From a review of selected literature, a working definition of social severance has been developed and the key attributes of the impact have been identified.
The literature reviewed has shown that the burden of social severance falls most heavily on those with limited mobility. This includes groups such as children, the elderly and people with disabilities for whom walking is a particularly important form of transport. A number of different severance effects have been identified. The principal components of social severance are physical severance which relates to the direct effect of a barrier on trips that are being undertaken, and psychological severance meaning the 'feeling' of being cut off.
A number of possible indices and measures are outlined. These can be used to identify situations where severance impacts are likely, and to assist in the quantification and reporting of the impacts.
In addition to the direct effect of delay to pedestrians, as they cross a busy road, the feeling of danger that is associated with a road are an important 'barrier' effect. In 1995 a pilot study was undertaken to develop a measure of the perceived danger. The resulting model is proposed as a tool to assess the direct effects of the perceived danger. Using examples from Denmark, Sweden and the United Kingdom, a framework for the assessment of severance impacts has been developed for use in New Zealand.
Keywords: Social severance, barrier effects, impact assessment, perceived danger