Busy street with pedestrians

Street mobility & accessibility

Dr Jennifer Mindell

Department of Epidemiology and Public Health, University College London

January 2014 to December 2016

Community severance is the ‘barrier-effect’ of traffic, or other transport infrastructure, on access to goods, services and people. It has been frequently mentioned as a health effect of roads in journal papers and in policy reports. However, evidence for health impacts is lacking because community severance is a multifaceted problem that is hard to measure.

AIM: The aim of the Street Mobility and Network Accessibility project is to develop a suite of tools to measure community severance.


  • To increase understanding of residents’ perceptions and priorities regarding CS;
  • To develop questionnaire tools to measure CS at the individual level, for use in future surveys and to validate spatial indicators for planning/urban design purposes;
  • To develop a CS index, based on relationships using readily available data, for use in epidemiological, public health, sociological, transport and engineering research and professional practice;
  • To obtain estimates of the values of reducing CS, through new stated preference surveys and existing literature on, for example, health impacts of limited mobility;
  • To test these measures, examining associations with individual, demographic, cultural, and/or infrastructure factors;
  • To analyse the impact of CS on wellbeing and other social outcomes.

Main project outcomes:

  • A modelling tool for local government use to derive the level and type of CS in an area from existing data;
  • A community level survey tool (also usable by local communities) that can identify suppressed travel and activity engagement, and the wider wellbeing consequences of CS;
  • Briefing notes for professional groups (transport planners and engineers, spatial planners, public health) on policy implications of CS and its mitigation;
  • Valuation of improvements to CS using willingness to pay data for assessment of policy options;
  • Monetised values of the wider economic, social and health effects of CS.

Working papers:

Working Paper 01: Initiating dialogue between stakeholders and establishing a common language for community severance through cross-disciplinary workshops (pdf, 440 KB) Output of a series of workshops attended by the project members and practitioners in fields related to community severance.

Working Paper 02: Quantifying community severance – A literature review (pdf, 840 KB) A review of the methods to identify and measure community severance.

Working Paper 03: The value of the barrier effect of roads and railways – A literature review (pdf, 280 KB) A review of the methods to estimate the economic value of community severance.

Working Paper 04: What do we mean by “community severance”? (pdf, 960 KB) Review of 60 definitions of community severance and proposal for a new definition.

Working Paper 05: Developing a questionnaire to assess community severance, walkability, and wellbeing: results from the Street Mobility Project in London (pdf, 620 KB) Methods to develop an health and wellbeing survey to measure community severance and results from the survey in the two London case studies.