THEME 9 - NEIGHBOURHOOD DESIGN AND STREET LAYOUT
Neighbourhood design and street layout are also important to travel. The relationships between buildings, streets and open spaces form the urban fabric that helps to give a neighbourhood its physical identity.
Note the image contrasts poor permeability to the north of the road and better permeability to the south. The original diagram has been amended to provide linear high-street style shopping to the south (originally mall style) and a more integral school location.
Neighbourhood design refers to the scale, form and function of buildings and open space (including streetscapes). Street layout refers to the pattern of local streets, for example as ‘traditional’ grid networks, cul-de-sacs or hybrid forms (Figure 12). Both can have an impact on generated travel patterns. Sustainability objectives move transport planning beyond increasing throughput, to include consideration of transport routes as ‘places’ as well as ‘links’ (for a useful working typology, see ‘Link and Place’, Jones, Boujenko and Marshall, 2008).
1. To what extent does neighbourhood design and street layout influence travel behaviour?
‘Traditional’ neighbourhoods, including fine-meshed grid-networks, are associated with higher non-car mode shares and trip rates whereas ‘suburban’ neighbourhoods and cul-de-sac style, poorly-connected street networks are associated with lower non-car mode shares and trip rates. Much of this is related to permeability and legibility for pedestrians and cyclists. Thus, neighbourhood design and street layout have some influence on the mode and frequency of local trips (especially non-work trips).
2. What best practice guidance is available on neighbourhood design and street layout?
Again there are wider contributing factors to travel, including context and personal preference, however there has been recent emphasis in the UK in terms of local streetscape design aspirations, including the Manual for Streets and other documents. These have mainly attempted to bring together the urban design and transport planning disciplines, and there is little evidence in terms of resulting travel behaviour. The assumption is that walking and cycling conditions and use improve. Many of the recommended elements of good design also contribute to increased safety and accessibility, thereby improving wider quality of life objectives.
“The physical form and qualities of a place, shape - and are shaped by - the way it is used and the way people and vehicles move through it. New development should help to create places that connect with each other sustainably, providing the right conditions to encourage walking, cycling and the use of public transport. People should come before traffic. Places that work well are designed to be used safely and securely by all in the community, frequently for a wide range of purposes and throughout the day and evening.” (PPG13, para 28)
“Matters to consider when assessing design quality include the extent to which the proposed development:
- Is easily accessible and well-connected to public transport and community facilities and services, and is well laid out so that all the space is used efficiently, is safe, accessible and user-friendly. […]
- Is well integrated with, and complements, the neighbouring buildings and the local area more generally in terms of scale, density, layout and access. […]
- Takes a design-led approach to the provision of car-parking space, that is well-integrated with a high quality public realm and streets that are pedestrian, cycle and vehicle friendly. […]” (PPS3, para 16)
Guidance on Transport Assessments is here.
Planning Checklist: Neighbourhood Design and Street Layout
Practitioners (in masterplans) are advised to:
9.1. Encourage walking, cycling and public transport use (where applicable) through permeable, well-connected, ‘traditional’ grid street networks.
9.2. Avoid circuitous, ‘surburban’, cul-de-sac street networks with few access points and lengthy routes to nearby locations.
9.3. In new developments, provide safe and high-quality walking and cycling environments throughout. In existing developments, consider retrofitting footpaths and adding cycle lanes to improve the travel experience of walkers and cyclists. Sustainable modes can be given priority in terms of journey length and time (sometimes known as ‘filtered permeability’).
9.4. Ensure integration between new development and adjacent built-up areas in terms of street network, public transport services, footpaths/cycle routes and design standards.
Evidence and Examples
The evidence given here is necessarily selective, but gives an introduction to the research on this topic. More details are found in the background technical report.
There are few studies which directly measure the travel associated with different neighbourhood and street network design types. Of those available, ‘traditional’ neighbourhoods and ‘good’ streetscape design, including fine-meshed grid-networks which facilitate walking and cycling, are associated with higher public transport, walk and cycle mode shares and trip rates, but with a weak significance because there are other factors involved in the rationale for travel. Conversely ‘suburban’ neighbourhoods and cul-de-sac style, poorly-connected street networks are associated with lower public transport, walk and cycle mode shares and trip rates.
In the UK, a recent study of Surrey found that energy consumption in the journey to work is lower in neighbourhoods with ‘traditional’ grid street patterns and higher in locations with cul-de-sac style street patterns. This is especially so when the cul-de-sac streets are remote from the village or town centre (Hickman and Banister, 2007a). Aditjandra et al (2007) develop similar conclusions.
Elsewhere, a study of the Netherlands looked at the effect of urban design, including home type, street design and neighbourhood characteristics, on shopping, social and recreational trips. The study found that these design characteristics (and traffic management) have a significant impact on trip frequency and mode choice for shopping, social and recreational trips but that socio-economic characteristics tend to determine commuter travel (Meurs and Haaijer, 2001).
Other research has looked exclusively at non-work trips. A series of studies of the San Francisco Bay Area, California have found that the frequency of walk trips to shops is higher in ‘traditional’ neighbourhoods (Handy, 1995) and that frequency of walk or bicycle trips is higher where pavements or cycle paths are present in a neighbourhood (Kitamura et al, 1997). A comparison of ‘traditional’ (mixed use, grid street network) and ‘suburban’ (separated use, curvilinear street network) neighbourhoods found that the greater proportion of walking and public transport trips in the ‘traditional’ urban neighbourhoods are substitutes for longer car trips undertaken in the ‘suburban’ neighbourhoods (Cervero and Radisch, 1996).
Another study of the San Francisco Bay Area found that distance travelled by car for non-work trips is lower where street connectivity is higher and the use of non-car modes for non-work trips is more likely in areas with higher walking quality factors. In this study, street connectivity is measured in terms of proportion of four-way intersections and walking quality is characterized in terms of pavement provision, street light provision, block length, and flat terrain (Cervero and Kockelman, 1997).
Recent best practice guidance in the UK deals specifically with neighbourhood design and local street layout, particularly in the context of new residential developments (although there are wider applications). The Manual for Streets (DfT, 2007b) provides advice on best practice in local street layout and design, with a particular focus on the internal layout of new residential areas. CABE’s Sustainable Cities website also promotes improved street design and layout, drawing on some of CABE’s work in this area.
Further reading here
Milton Keynes / South Midlands - Inspired by the Manual for Streets and the streetscape design agenda, Northamptonshire County Council has developed its own Transportation Design Guidelines for Residential Developments to (further) raise development standards.
Northstowe, South Cambridgeshire - A new development at Northstowe (Cambridge) provides a good example of contemporary best practice in neighbourhood design and street layout.
Sherford, Plymouth - A new development at Sherford (Plymouth) provides a good example of contemporary best practice in neighbourhood design and street layout.