THEME 8 - MIX OF USES
Mix of uses refers to the degree to which different land uses are contained within a geographic area, generally a building, street or neighbourhood. It is often measured in terms of proximity of local facilities to households. ‘Mixed-use development’ generally refers to a mix of uses within a development site. The location of key facilities such as health facilities and schools in relation to other uses should be assessed and planned for at the city-region, sub-regional and local scales (e.g. through the Local Development Framework or local masterplans).
The aim of mixing land uses is to provide opportunities for individuals to undertake multiple activities in one trip (as opposed to increasing accessibility), to shorten trip lengths and to encourage non-motorised trips through a diverse urban environment (e.g. a high street).
1. Is travel behaviour in urban areas with a mix of uses significantly different than in single-use areas?
Overall, a mix of uses in primarily residential areas appears to influence mode share, trip distances and car ownership, and a mix of uses in primarily commercial areas appears to influence mode share. However, a mix of uses is often associated with higher density and a ‘traditional’ street network so there are likely to be co-linearity issues. Certainly, the combined effect of these factors can make a strong contribution to encouraging sustainable travel.
“Mixed use development can provide very significant benefits, in terms of promoting vitality and diversity and in promoting walking as a primary mode of travel. However, it should not be assumed that the juxtaposition of different uses will automatically lead to less car dependency. Planning policies should therefore aim to:
1. Produce a broad balance at the strategic level between employment and housing, both within urban areas and in rural communities, to minimise the need for long distance commuting;
2. Focus mixed use development involving large amounts of employment, shopping, leisure and services in city, town and district centres, and near to major public transport interchanges;
3. Encourage a mix of land uses, including housing, in town, suburban and local centres”. (PPG13, para 30)
“[…] Policies should promote mixed use developments for locations that allow the creation of linkages between different uses and can thereby create more vibrant places.” (PPS1, para 27)
Planning Checklist: Mix of Uses
Practitioners (within masterplans) are advised to:
8.1. Consider locating essential community facilities (e.g. grocers, local schools, bank) within walking distance of all homes in a neighbourhood in order to reduce travel distances and de-incentivise car ownership. This will require a certain density of housing in order to concentrate demand sufficiently for the shops and services to be economically viable.
8.2. Identify complementary uses such as a day-care and fitness centre or bookstores and cafes and support building types that facilitate co-location so that individuals can reach more activities per trip.
8.3. Where public transport is available, promote retail uses that complement employment centres in order to increase public transport mode share.
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.
A way of measuring the degree of land use mixing is in terms of proximity of local facilities to households. Recent analysis of the UK National Travel Survey (NTS) using data on proximity of local facilities suggests that this has a positive effect on mode choice (i.e. more non-car trips) but more so on car ownership, particularly multiple car ownership (Dargay and Hanly, 2004). This implies that harmonising increases in density with the provision of mixed use areas along public transport corridors may lead to sustainable travel benefits.
Earlier research also found that the diversity of services and facilities in close proximity to households reduces distance travelled (Banister, 1996; Farthing et al, 1995, 1997). More recent research using multi-variate analysis in Surrey has come to the same conclusion (Hickman and Banister, 2007a).
Research in the Seattle Area (Washington) found that work trip distances and times are shorter in areas of higher population density, higher employment density and greater land use mix (Frank and Pivo, 1994).
In the San Francisco Bay Area, the greater proportion of walking and public transport trips in traditional urban settings (i.e. with a mix of uses and grid-like street pattern) appear to substitute for longer automobile trips (Cervero and Radisch, 1996). Similarly, further research found that trip lengths are shorter in ‘traditional urban settings’; the combination of central locations, fine land use mixes, and grid-like street networks produces shorter trips. Walking and, to a lesser degree, public transport mode share is also higher in ‘traditional urban settings’ (Ewing and Cervero, 2001).
In a wider study of 11 metropolitan areas across the US, logit and regression analysis indicated that use of public transport and walk/bike modes is more likely where commercial and non-residential uses are nearby (within 300 feet of residence) and in this case a mix of uses is as important as density (Cervero, 1996). Moreover, walking, cycling and public transport mode shares are greater in locations where shops are located close to office buildings (Cervero, 1989).
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Didcot, Oxfordshire - The Great Western Park urban extension in Didcot (Oxfordshire) will include two new primary schools, a secondary school, open spaces, local shops and services, play areas, two community centres and a health centre in addition to 3,300 new homes (30% of which will be affordable).
Longbridge, Birmingham - The mixed-use brownfield redevelopment project at Longbridge has designated zones for lower and higher degrees of land use mixing. The zone with greatest land use mix includes housing, retail and employment centres, the highest density and is oriented around a rail station.