Planning for sustainable accessibility: Developing tools to aid discussion and decision-making

Abstract

Planning policy goals now emphasise the need to plan for accessibility and it is clear that increasing the mode share of public transport is a key requirement. One of the enduring issues has been how to embed these policy aspirations into mainstream planning practice. There is considerable diversity of approach to measuring accessibility with no single perfect accessibility measure. Applications of accessibility tools in planning practice have tended to be single issue focussed. There remains a gap in accessibility tool development capable of providing a multi-focus perspective both on land use and transport integration, which also consider accessibility as a city wide application where access from every centre to every other centre is considered. In addition to these shortcomings, there is also a strong need for accessibility tools that can enhance the understanding of land use transport integration, not only for professional practitioners but for a wider range of stakeholders. To achieve this, the inputs and outputs of accessibility tools need to be communicated in an ‘accessible’ way too.

This paper demonstrates the application of a new accessibility planning tool and the way in which it has functioned as a trans-disciplinary communication tool to demonstrate the integration between land use and transport in a way that practitioners and stakeholders can fully understand. We show that it is critical to apply several measures in combination in order to present the necessary information to inform debate and deliberation. The most important driver, however, will be to apply measures framed around the way individuals make decisions in their travel plans—particularly in choosing between car and public transport. We argue that the dissemination of accessibility measures through visually well-represented media can significantly enhance understanding, making a contribution towards a productive discourse on future directions for urban form and mobility.

Introduction

Policy aspirations for planning cities framed around accessibility rather than mobility have been promoted for some time (Cervero, 1997, Vigar, 2002). The thinking captured by distinguishing between mobility and accessibility planning is that the former approach assumes that city dwellers will gain access to services required to support their daily needs through transport systems based on high levels of mobility by car, to some extent regardless of the relative location of land uses. By planning for accessibility, the approach incorporates a need to consider proximity of land use activities as well as the transport network itself. This new approach then demands a new way of thinking about the integration of land use and transport in city planning.

Ideas about accessibility planning have been framed within the context of concerns for improving the sustainability of cities and of achieving more sustainable transport outcomes. The core solutions have been seen as limiting urban sprawl, both in terms of its spatial extent and in terms of limiting the scattered dispersal of activities within the urban area (instead concentrating activities around public transport), and providing for a range of travel choices as an alternative to the car. Within this approach one of the most popular planning approaches is transit-oriented development (TOD). This is a development strategy being pursued in many city-regions worldwide. The aim of TOD is to strengthen the integration between urban development and public transport systems by creating places in which public transport is readily accessible for many activities. Typically TOD involves creating medium/high-density areas of mixed land use concentrated within 800 m walking distance of significant transit stops. Within this mixed-use precinct the idea is that complementary land use activities are placed in close proximity to each other, thereby allowing people to walk between uses. TOD aims to reduce car-based travel by increasing public transport patronage, walking and cycling. It is thus argued that TOD provides a more environmentally sustainable form of urban development by reducing the need to travel and facilitating a modal shift among residents away from the car.

In recent years TOD has particularly been taken up in US cities as a way of counter-acting sprawl. There is some convergence in TOD policy approaches across continents as European planning systems embrace these ideas too. For example, in the UK, attempts to link development more closely to public transport opportunity have a long history. Its roots can be seen in the 1994 Planning Policy Guidance Note 13: Transport (DoE & DoT, 1984) which argued for reduced reliance on the private car by requiring that new development be sited where there was genuine transport choice. A revision of this policy added an accessibility measure to the assessment process. Again a later policy indicated,

‘that new development is located where everyone can access services or facilities on foot, bicycle or public transport … [and to] encourage accessible public transport provision to secure more sustainable patterns of transport development. Planning should actively manage patterns of urban growth to make the fullest use of public transport’ (OPDM, 2005: Para 27).

In Australia ‘land use transport integration’ is seen as a means of achieving sustainable travel outcomes, a message reinforced by the National Charter on Integrated Land Use and Transport Planning (DOTARS, 2003). TOD is seen as a principal means of achieving integration and as such has been embraced in most cities’ metropolitan strategies in recent years (Gleeson, Darbas, & Lawson, 2004).

It is clear that city planning must be framed around public transport, but this leaves open another question—what quality of public transport system will deliver these sustainability objectives? The significance of public transport for urban mobility in developed cities varies greatly from just over 2% of all trips in Atlanta and Los Angeles to between 26% and 31% of all trips in Barcelona, Vienna and Singapore (Kenworthy & Laube, 2001). Australian cities range between 4% and 10% of all trips. This variation is influenced, for example, by historic and current policy priorities for infrastructure development and the form of urban settlements, and the competitiveness of different modes in terms of speed and pricing (Gleeson et al., 2003, Newman and Kenworthy, 1999). Planning goals now emphasise the desirability and importance of increasing the mode share of public transport in their policy documents (see for example the Melbourne 2030 metropolitan strategy (DOI, 2002) and Perth's Network City strategy (WAPC, 2004)). Translating these goals into practical action, however, has proved a formidable political challenge and remains the subject of ongoing passionate public debate, particularly in Melbourne (Bergmaier, 2006, CES, 2007, Mees et al., 2006, Scheurer et al., 2005).

It is clear that in policy terms planning for accessibility is a key requirement. One of the enduring issues has been how to turn these policy aspirations into mainstream planning practice. There are examples where accessibility tools have been developed and applied in planning practice. For example the London Borough of Hammersmith and Fulham developed the ‘Public Transport Accessibility Levels’ tool (‘PTALS’) to assist in decision-making in locating development and setting development control standards. The approach of PTALS is to produce contour maps which indicate the relative accessibility of places to the public transport network derived from an assessment of walking time, waiting time, frequency and reliability of public transport services (Rowe, 1999). In the Netherlands, accessibility maps are used in decision-making around city planning and in transport network planning. To date these types of applications in planning practice have tended to be single issue focussed; there remains a gap in accessibility tool development which enables a multi-focus perspective both on land use and transport integration and is capable of considering accessibility as city wide application where access from every centre to every other centre is considered. In addition to this shortcoming, there is also a strong need for accessibility tools that can enhance the understanding of land use–transport integration, not only for professional practitioners but for a wider range of stakeholders. To achieve this, the inputs and outputs of accessibility tools need to be communicated in an ‘accessible’ way too.

We argue that new accessibility tools, designed with the above parameters in mind, will have a critical role in forging constructive collaborations between transport and land use planning agendas. They must have a function of trans-disciplinary communication if the integration between land use and transport is to be fully understood and achieved. A focus on accessibility can introduce land use considerations into conventional transport models, and conversely, land use planning can be enhanced by better illustration and understanding of the mobility implications of urban form. We argue that the dissemination of accessibility measures through visually well-represented media can significantly enhance understanding, making a contribution towards a productive discourse on future directions for urban form and mobility, engaging a wide range of stakeholders and thus helping to bring this important challenge further into the public arena.

In our own planning practice and research we have found that land use–transport integration to achieve more sustainable travel outcomes is not well understood by practitioners. Despite the policy aspirations, practice has for the most part remained ‘segregated’. By this we mean that land use planners develop metropolitan plans and strategies, transport modellers then assess these using conventional four-step models primarily to check where car-based congestion will occur, while public transport planners develop their own capital investment plans for future public transport networks. Rarely do these practitioners work together in an integrated fashion. In our experience they ‘talk the talk’ (meaning that they acknowledge the need for land use–transport integration and for sustainable accessibility) but do not demonstrate how to actually ‘walk the talk’ (as in producing integrated strategies and development concepts).

This paper, which describes and positions the accessibility planning tool we have developed, is the product of our own research inquiries into how to deliver better land use–transport integration framed around sustainable travel based in part on the above concerns. We have drawn from a range of experiences over the years. Curtis draws on a research background in personal travel behaviour change and in city form and structure, including her work in developing a new spatial framework for metropolitan Perth, as well as her practice based experiences as a planning commissioner. Scheurer draws on his experiences as a public transport advocate and researcher in urban design and in ‘best practice’ public transport systems. Our work started with a simple question—how could we distinguish between three locations by their accessibility characteristics. We wanted to do this so we could compare how accessibility changed with the opening of a new passenger railway line in Perth. We wanted to examine what the relationship was between some objective measure of accessibility and people's actual travel behaviour. In developing a way of measuring accessibility we realised a new planning tool that appears to be resolving some of the above challenges. We have continued to develop this tool in order to answer several other questions including scenario planning for future urban form and future public transport networks based around sustainable accessibility, and in thinking about benchmarks which can be used to set standards for the state of public transport accessibility for comparisons between cities and stages of development.

The paper is structured as follows. In Section 2 we provide a comprehensive review of the different strands of accessibility definitions and measures found in the literature and in planning practice. In Section 3 we trace the origins and evolution of a specific accessibility model (SNAMUTS) developed by the authors. In Section 4 we describe how the SNAMUTS tool has been applied in several collaborative ventures with planning practice, including: a comparison of the state of public transport accessibility before-and-after the opening of a new passenger railway (Section 4.1); the use of SNAMUTS for future growth plans (Section 4.2); an exploration of different cities’ public transport systems in order to develop benchmarks (Section 4.3). Section 5 positions SNAMUTS in current planning practice, particularly relative to other transport models. Section 6 concludes the paper.