Appendix H: Further research considered
Appendix H: Further research considered
36. Further research and guidance considered
36.1 Introduction
36.1.1. This Appendix to the main research report entitled "Inclusive Design in Town Centres and Busy Street Areas" summarises further research considered in the development of recommendations outlined in the main report. These are:
- Factors when considering segregation between cyclist and pedestrians;
- Shared space – the impact of shared space on safety;
- Shared space – the impact of shared space on the level of comfort of users ('user versus avoiders'); and
- Pedestrian crossing intervals.
36.2 Factors when considering segregation between cyclists and pedestrians - pedestrianised areas
36.2.1. When considering cyclists and pedestrians in town centres and busy street areas, there is existing research and guidance that can be considered. The Transport Research Laboratory (TRL)[99] research report 'Cycling in vehicle restricted areas'[100] outlines that pedestrians change their behaviour in the presence of motor vehicles but not in response to cyclists. Cyclists, however, respond to pedestrian density, moderating their speed, dismounting and taking other avoiding action when necessary. The research quoted in this paper is from a similar piece of TRL research undertaken in 1993, with the 2003 research corroborating the original findings that it is pedestrian density which has the most influence on cyclist behaviour. The research paper does discuss concerns expressed by the visually impaired on the subject of segregation and suggests "such differentiation can be achieved using low sloping kerbs tactile differentiation may assist blind and partially sighted people".
36.2.2. Current practice is illustrated by Transport Scotland's 'Cycling by Design'[101] (para 6.1.2) which takes this research into consideration and defines a framework for considering the combined density of pedestrians and cyclists per metre – this is outlined in Table 17.
| Combined density (users / hr / m)* | Recommended arrangement |
| < 100 | Shared use is usually appropriate (cycles give way). |
| 101 – 199 | Segregation may be considered. |
| > 200 | Segregation should be considered. |
| * Combined density per hour: number of pedestrians and cyclists per hour per metre width. |
36.2.3. 'Cycling by Design' outlines the following in relation to use by disabled people:
"Many disabled people, particularly those who are visually impaired, find shared facilities intimidating and stress the importance of segregation by levels. Visually impaired people use kerbs as the basis of the concept that 'up means safe'".
36.2.4. It should be noted that 'Cycling by Design' is being updated, and Cycle infrastructure design (LTN 1/20) was published in July 2020.
36.2.5. The research team further considered other standards. Much of the UK cycling guidance is drawn from the Dutch CROW[102] (equivalent TRL) research and guidance. The CROW 'Design Manual for Bicycle Traffic' guidance (updated in 2017) is based upon on empirical research and suggests the use of threshold indicators in relation to pedestrian density and cyclists sharing the same space. These thresholds are presented in Table 18.
| Pedestrians per hour per meter of available profile width | Recommended design solution |
| < 100 | Full mixture. |
| 100 – 160 | Segregation: vehicle path with non-sectional profile (no level difference). |
| 160 - 200 | Segregation: vehicle path with sectional profile. |
| > 200 Combination not desirable. |
36.2.6. It should be noted that the CROW guidance outlines when visual segregation is used, it should ensure the cycleway is clear and easy to recognise. When level segregation is used, it should be a 'soft' segregation (tactile, road marking) that is integrated into the physical street design. 'Hard' level segregation (a kerb) should be avoided as it makes leaving and entering the shared area uncomfortable for cyclists as well as potentially presenting trip hazard for pedestrians.
36.2.7. The CROW manual makes reference to other studies that re-affirm cyclists appropriately modify their behaviour with increased pedestrian density. There is also reference to low level accident potential between cyclists and pedestrians and when collisions do occur the level of severity is low.
36.2.8. Key message H1 - Sharing a town centre or busy street space between pedestrians and cyclists should be considered in the light of the pedestrian demand. At higher levels of pedestrian demand segregation is advised in order to avoid negatively impacting on disabled street user access. An alternative route which allows cyclists to bypass these areas during high pedestrian demand periods should be provided.
36.2.9. In existing guidance in Cycling by Design (section 6.4.1) and Cycle Infrastructure Design (LTN 1/20) designers are being asked to give careful consideration to the provision of defined cycle routes through pedestrianised areas (i.e. where the final destination is not the town centre / busy street) which may be desirable from the pedestrian and cyclist perspective. However, this could lead to higher cycle speed and greater potential for conflict with pedestrians. Therefore, the public realm design should aim to create an attractive and functional environment in which cycle speeds are low and pedestrians clearly have priority.
36.3 Research into accident potential and street design
36.3.1. It was outlined in the Literature Review (Appendix A) that there is mixed evidence as to whether the introduction of shared use in town centres and busy street areas has resulted in increased injury accident rates.
36.3.2. The CIHT report on 'Creating better streets: Inclusive and accessible places'[103] found that in most locations examined injury accident rates reduced. 'Stage 1: Appraisal of Shared Space' research undertaken by MVA Consultancy for the DfT in 2009[104] stated the following, referring to a new approach for analysing injury accident rates related to shared space:
"One of the conclusions is that the new approach (shared space) can be applied for traffic volumes of up to 6,600 motor vehicles per 24 hours without causing a noticeable difference in the number of accidents. Objective statistics show that there is no difference in road safety between the new planning approach and a traditional road layout. The study has shown, however, that applying the new approach to volumes of 13,700 vehicles per 24 hours will have an adverse effect on the number of accidents. There is a grey area for traffic volumes of between 6,600 and 13,700 vehicles per day."[105]
36.3.3. The MVA report goes on to conclude with regards to accidents:
"There is some evidence from the Netherlands that at locations with motorised traffic flow of greater than c14,000 vehicles per day Shared Space layouts may have more casualties, relative to traditional layouts and that risk to cyclists may be increased in these settings. It is not presently possible to verify this effect at UK sites as there are no examples of the application of Shared Space at sites with such vehicle flows and cycle flows in the UK are currently generally lower than in the Netherlands."
36.3.4. The more recent CIHT 'Creating better streets: Inclusive and accessible places' report gives an example of sites with traffic volumes in order of 25,000 vehicles per day with a reduction in accidents over three years.
36.3.5. Care needs to be taken in considering these absolute values as there are a number of contributing factors to accidents in addition to traffic volume and speed. These higher vehicle flows could be due to a good street design that considers the wider needs of the area as well as taking a holistic approach to considering safety and the needs of all street users.
36.3.6. There needs to be a clear distinction between the different types of shared spaces designs in line with the CIHT 'Creating better streets: Inclusive and accessible places' report.
36.3.7. Further consideration needs to be given to the definition of 'low flow / low speed' criteria.
36.3.8. Key message H2 - Further research is required into the injury accidents associated with existing 'shared space' sites or similar design concepts within the UK. The research needs to include specific reference to vehicle speeds and flows, as well as the form and nature of the design, including consideration of level surfaces and kerbs with associated tactile paving.
36.4 Research on the level of comfort of users ('users versus avoiders')
36.4.1. As described in Appendix A, Karndarcharuk (2015[106] 2014[107]) outlined that "persons with reduced mobility avoided shared space, and most reports related to visually impaired users". This Auckland-based study researched a number of shared space areas (level surface with tactile demarcation) as well as a control site and appraised them against the performance criteria of Placemaking, Pedestrian Focus, Vehicle Behaviour Change, Economic Impetus and Safety for all users. The statistical analysis revealed that the performance criteria of 'Pedestrian' and 'Safety' had a commanding influence over the other performance measures, with the interconnectivity of the five objectives influencing the perceived success of the urban shared spaces.
36.4.2. This research was reflected in comments made during the disabled street users focus groups (included under Appendix C), in which visually impaired street users reported adapting their behaviour to avoid areas (regardless of the street design of the area) if they expect to be too uncomfortable in that space due to pedestrian volumes and unpredictable movement. This was referred to as 'different kinds of busy' (ref para 4.5.11 in Appendix C) by one participant. Participants also explained that they often found wide open spaces added to this feeling of discomfort.
36.4.3. The supporting research for LTN 1/11 Shared Space[108] outlined the concept of 'users versus avoiders'. The research states that some participants from each user type (visually impaired, those with reduced mobility, learning difficulties and deaf / hard of hearing) avoid certain streets due to them being busy in terms of pedestrians and vehicles. However, the research did not quantify the number of 'avoiders' nor attempt to assess the possible impact of their behaviour on the number of reported injury accidents in the new street layouts. This is a significant research gap.
36.4.4. Key message H3 - Disabled street users may adapt their behaviour and potentially avoid an area in response to feelings of discomfort resulting from higher pedestrian flows, i.e. an area that is comfortable for a disabled street user to access at a lower level of pedestrian demand may not be comfortable at a higher pedestrian demand.
36.4.5. However, it should be noted that accessibility for some disabled street users may still be restricted due to the following factors outside of the designer's control:
- Type of disability.
- Level of personal adaptation the street user has.
- The level of (unpredictable) activity on the street.
36.5 Pedestrian crossing intervals
36.5.1. There is no existing guidance on pedestrian crossing intervals and / or the number of crossings.
36.5.2. Napier University undertook research that examined STATS19 data which shows that in urban areas in Scotland, over half of pedestrians killed or seriously injured are crossing the road away from junctions and away from where there is any kind of formal crossing facility. Often, signalled or zebra crossings can be 600m apart or more, even in urban areas, and therefore can require up to an additional 1-2km in walking distance to use a formal crossing. It is unsurprising, therefore, that pedestrians continue to risk crossing at locations without a formal crossing facility in order to avoid such increases in trip length.
36.5.3. Key Message H4: More formal and informal crossings are needed overall.
36.5.4. While there is a need for more crossings in town centre and busy street areas, consideration needs to be given to walking distance without rest, as outlined section 2.4 of the DfT 'Inclusive Mobility' guidance.
| Impaired group | Recommend distance limit without a rest |
| Wheelchair user | 150 metres |
| Visual Impaired | 150 metres |
| Mobility impaired using stick | 50 metres |
| Mobility Impaired with walking aid | 100 metres |
36.5.5. There is some additional guidance in the DfT 'Inclusive Mobility' guidance which relates to wheelchair users (para 3.1.3):
"Dropped kerbs and raised crossings (3.13): Level or flush access is essential for the majority of wheelchair users. Such access, either by dropped kerb or raised road crossing must be provided at all Zebra and controlled crossings and at other places on side roads, access points to parking areas etc. used by pedestrians. On longer side roads and residential roads dropped kerbs should, where possible, be provided every 100 metres to avoid the need for wheelchair users to make lengthy detours to cross the road having given due consideration to desire lines for pedestrians and inter visibility."
36.5.6. The is some additional guidance in the DfT 'Inclusive Mobility' guidance which relates to improving access at bus stops (section 6):
"Regular bus services designed particularly with elderly and disabled people in mind have bus stops at more frequent intervals, typically every 200 metres. This figure is in accordance with research that shows that for disabled people, bus use falls off sharply if the distance is more than 200 metres (250 metres for non-disabled people). Where there are places that will be used by disabled people, such as residential care homes, day centres etc., bus stops should be sited as close as possible and should have a pedestrian crossing (with dropped kerb) in reasonable proximity."
36.5.7. While there is a lack of guidance on the intervals of crossings for disabled street users, the current limited information highlights that longer detours make the crossing less attractive to disabled and non-disabled street users alike.
36.5.8. The lack of guidance and research would suggest that this is a site-specific matter and requires consultation with the local community - in particular the disabled street users – to ensure that crossings are suitably sited and provided with sufficient frequency.
36.5.9. Key message H5: Consideration should be given to relocation / rationalising existing crossing facilities with regards to walking distance without rest in terms of detours for current users and that any proposal that increases the walking distance to a crossing needs to consider rest facilities to support older and disabled users, but without creating an obstruction.