4. Literature review and key findings
4.1 Introduction
4.1.1. The Literature Review was led by the Transport Research Institute at Edinburgh Napier University. This chapter provides a summary extracted from the Literature Review included in Appendix A and concludes with an overview of the key findings which were considered in the development of the recommendations.
4.1.2. The objective of the Literature Review was to provide evidence of methods and approaches that assist the delivery of inclusive design environments within town centres and busy street areas.
4.2 Overview of literature review
4.2.1. The focus of the Literature Review was to report on peer reviewed and grey literature (non-peer reviewed) addressing the design of town centres and busy streets in the quest for designs which are acceptable to all vulnerable road user categories. In order to be included in the Review, the papers needed to give some consideration to mobility impairments.
4.2.2. The search criteria were broken down as follows:
- Target audiences/populations included in interventions - all adults and children.
- Study design - prioritising reviews of the literature, but also considering single studies, which included qualitative research.
- Timescale - January 2008 to September 2019.
- Geography – a global literature search for papers published in English.
Literature searches
4.2.3. Search terms applied were: inclusive design; shared space; inclusive street design; walk; mobility impairment; sensory impairment; disable; high street; kerb (curb); shopping street; streetscape material; colour (color); texture; surfaces; street delineation; street clutter; tactile pavement / paving; vehicle / pedestrian segregation; disabled parking; bus stop access; severance; pedestrian crossing; traffic speed / volume; accidents; inclusive engagement / consultation; equality engagement / consultation; disability engagement / consultation.
4.2.4. These were augmented by over 100 search words and terms suggested by members of the working group. As some of the new search terms duplicated terms in the above list, they were prioritised through discussions within the research team.
4.2.5. Search terms subsequently added were: co-design; wayfinding; street design; shared use; shared surface; delineation; disable / disabilities; blind; partially sighted; deaf-blind; deaf; cognitive impaired; road traffic collision / conflict; access; slope; gradient; pedestrianisation; kerb (curb) height; and cycle way.
4.2.6. The search engines used were Transport Research International Documentation (TRIDS); Transport Research Board (TRB); ScienceDirect; and Google Scholar. References from studies were also examined to seek additional studies. In addition, grey literature drafted by government departments and agencies and road safety institute reports was also included.
4.3 Assessment process
4.3.1. The literature review found 38 studies in scope. Given that seven of the studies were reviews of the literature, the total number of individual studies referred to is greater than 38, and some single studies also summarised aspects of the literature in setting their own study in the wider context of the shared space literature. After searches had been undertaken to find studies and abstracts, these were checked to assess whether it was likely that they were in scope or out of scope.
4.3.2. A common procedure in identifying and examining a body of literature is to group studies under themes. For this Literature Review the themes are:
- Reviews (7).
- Single studies - design and use (23), non-visual impairments (2) and engagement and consultation (6).
4.3.3. Each theme is drawn on in detail in covering the range of topics identified in the Review, in order to set out a cohesive narrative which seeks to draw together the evidence found.
4.3.4. A total of 20 studies were from the UK, four from elsewhere in Europe and 14 outside Europe were included in the literature review. All studies are listed with their full citation in Appendix A.
4.4 Summary of key findings
4.4.1. At the general level, there needs to be greater recognition of the needs of all users, including people with sight loss (Imrie and Kumar, 2011; Smithies, 2015).
4.4.2. The views and feelings of vision-impaired people are not a significant part of the policy-making process (Imrie, 2013).
4.4.3. There is a need for clear guidelines on how to prevent the identified issues from occurring in newly designed shared spaces and how to improve existing shared-space schemes (Havik et al, 2015; Audrey, Leonards, Damens, 2017). This is supported by Imrie and Kumar (2011) who state that more detailed guidance is required on the development and implementation of shared space.
4.4.4. The seeming lack of consistent standards provides designers with a blank canvas when creating shared-use areas, often meaning that the needs of vulnerable road users, including blind and visually impaired users, are forgotten among the aesthetic details. Shared spaces should not be a uniform material but have distinct safe areas. Boundaries within the shared space should also be present to create an environment that is easily identifiable and understandable to blind and visually impaired users. A consistent approach to designing for blind and visually impaired users should be introduced. This could be achieved by establishing national standards and specifications with appropriate enforcements (Smithies, 2015).
4.4.5. Communication emerges as a challenge to designers and implementers. Communication should be improved e.g. between guide-dog trainers and roads / highway authorities. Authorities should consult with blind and visually impaired organisations, seeking their opinions before the detailed design stage (Smithies, 2015). As such, roads / highway engineers should be provided with training opportunities to develop their skills in designing for vulnerable road users (Smithies, 2015).
4.4.6. An expectation of general enjoyment of greater pedestrian space for one group comes at the price of a limited expectation of these benefits for another group. This suggests that even within the broad category of those with impaired mobilities, there is not only an accessibility issue, but also a challenge to the equity of the scheme (Tyler, 2017).
4.4.7. The 'evidence gaps' need to be addressed, particularly in relation to personal safety issues (Imrie and Kumar, 2011).
4.4.8. While the level and quality of research available is not extensive and in depth in relation to persons with an impairment or combination of impairments, the literature does present some aspects in the research that would suggest that there are four key areas with associated key findings.
4.4.9. The key findings below (indicated with the relevant "LR" codes) are referenced in the further chapters of this report to indicate where they have informed principles and recommendations. Full details are in Appendix A.
Inclusive engagement
- LR1 - Inclusive design[6] can be better achieved through greater efforts at consultation and engagement.
- LR2 – Engineers and designers should consult with a range of organisations representing users with reduced mobility seeking their opinions on an ongoing basis during the proposal and design stages of all schemes.
Inclusive Physical Design Measures
- LR3 - There is mixed evidence as to whether the introduction of shared space use on high streets and busy streets has increased accidents.
- LR4 - There is research that reports persons with mobility impairment avoid shared space, and most reports relate to visually impaired users.
- LR5 - The evidence shows that there is still some debate on the need for kerbed edges, however there is consensus that detectable demarcation between motorised traffic and pedestrian in 'shared space' is required.
- LR6 - 'Safe Space' areas that are strictly reserved for pedestrians appear to be a well-supported compromise as a design solution and give confidence to the mobility impaired user.
- LR7 - There is evidence which suggests that some measures to support some disabled people can have an impact on users with other impairments and there are limited studies into persons with more than one type of impairment.
The need for more research and definition
- LR8 - There is no agreed definition of 'shared space' in practice and this is reflected in the inconsistent approach to design.
- LR9 - There is a need for guidance on street layout for emerging and existing 'shared space' schemes which should be supported by more research.
- LR10 - There is limited high quality (robust) literature and research on inclusive design from the perspective of the users with mobility and or sensory impairment.
- LR11 - Limited research exists on mobility experiences of persons with cognitive functional limitations.
Inclusive design training
- LR12 – Engineers and designers should have the opportunity to be trained to design for vulnerable road users.