Intermodal Transport and Mobility Infrastructure by E.A. Beukes and M.J.W.A Vanderschuren
Volume: 1 issue 6 |  Friday, 25 June 2010 |  E.A. Beukes and M.J.W.A Vanderschuren  |  0 comment

Adapted from Chapter 3 of the Sustainable Transport and Mobility Handbook

Activities are what drive individuals and societies. We carry out activities to work, play, learn, gather resources, and so forth. These activities cannot all be conducted at the same location, and hence the need for transportation arises. So, in fact, all transportation is activity driven. Therefore, the nature of the activity has an influence on the nature of the trip, and consequently the nature of the infrastructure provided to support that trip.

This presents planners with a fundamental problem. Different activities are conducted by different people, in different locations, using a range of modes of transport, at various times during the day. The infrastructure provided cannot be tailored to meet the needs of every individual trip perfectly – and yet the infrastructure provided must ensure that all trips can be made as safely, quickly and affordably as possible.

To this end, an entire scientific and engineering community has devoted itself, for well over a hundred years, to studying the provision of transportation infrastructure so that the movement of people, goods and services are optimised. From this collective effort, a host of guidelines, design manuals, best practice manuals and countless scholarly and academic publications have emerged covering all facets of the practice.

In recent decades, the practices espoused in these manuals have come under review regarding their effect on the sustainable provision, operation and management of the transportation systems and networks (Newman and Kenworthy, 1989; Commission of the European Communities, 1990; Greene and Wegener, 1997). This chapter identifies the problems and pitfalls when planning sustainable transportation infrastructure, and looks at the approaches to solve problems. The reader is directed towards the correct methodologies in solving these problems in a sustainable way.

Integrated planning and current practices

A continued theme amongst the guiding literature for transportation planning in South Africa is the importance of encouraging a multimodal transportation environment that addresses the economic inequities in our towns and cities, that protects the environment from the effects of transportation, and that stimulates the development of a healthy social realm (CoCT, 2005; NDoT, 2003). Furthermore, the inseparable relationship between transportation and land use is emphasised and planners are encouraged to view land use and transportation as being almost two sides of the same coin (Vanderschuren, 2003).

Land use and transportation are intrinsically linked, as changes in land use often initiate changes in trip making patterns, and vice versa. In South Africa, the effects of poor integrated transport and land use planning are highly evident in the low population densities that are common in our cities, and the long distances that people are often forced to travel as a result.

Urban sprawl has become a major spatial development characteristic of South African cities. The majority of the population has been forced to live in segregated, isolated and hostile townships, separated from each other by freeways and buffer zones. This has created a vastly inequitable and inefficient city in which the poor are marginalized from urban opportunities (Pistorious, 2002) (cited in Vanderschuren, 2003).

The problems are further compounded by historically poor investment in public transport infrastructure, especially in poor neighbourhoods (CoCT, 2006; Behrens and Wilkinson, 2001). The net result is that it is often the poorest people in urban centres who spend the largest percentage of their disposable incomes on transport costs (NDoT, 2003). This situation is socially, environmentally and economically unsustainable.

One of the major hurdles to improving circumstances is that planning and design practice has tended to be very automobile-centric, with all of the commonly used road design manuals focusing almost exclusively on the needs for sustaining motorised trips. Planning and design concerns generally relate to minimising congestion and maximising throughput, and avoiding accidents where possible.

There is very little thought given to the needs of NMT or public transport road users. It is therefore not surprising that the overwhelming bulk of project funding is dedicated towards improving conditions for motorists, creating unsustainable settlements.

Planning for multiple modes:

The majority of urban streets serve various roles, having to accommodate the needs of multiple modes of transport, and the needs related to mobility (through users) and access (locale users). In addition, urban streets may perform a variety of civic, ceremonial, political, cultural and social roles, as well as commercial and economic roles, in addition to their movement roles (Svensson A et al, 2004).

This multiplicity of roles implies that the functions performed by the road, and the needs of those who use it must be thoroughly evaluated and understood before an appropriate planning recommendation can be made.

Current planning practices in South Africa do not facilitate an assessment of this nature. Practice presently involves the classification of the route into one of five hierarchical categories, related to the expected volume of vehicular traffic on the road, and to its location in the road network. Each category is based on a set of norms related to operating and design speeds, cross sectional parameters and modal inclusivity (which modes are allowed to operate where). Access is defined as access to properties, and theoretically all roads are said to lie somewhere on a spectrum between mobility only routes and access only routes (FHWA, 2001). These norms are then expanded to derive design parameters, which are applied when developing design recommendations.

This generalised approach to road planning has limited the influence that locale specific contextual factors can have. The practice has become artificially skewed towards maximising mobility for through users in order to improve overall network flow conditions and alleviate localised congestion. In addition, where intermodal safety is of concern, the default approach is to limit the freedom of movement of vulnerable road users irrespective of the contextual setting.

To read the rest of the chapter, including a look at the role of context in road planning and at assessing transport sustainability, order the Sustainable Transport and Mobility Handbook online here.

References:

Behrens, R. and Wilkinson, P., 2001, South African urban passenger transport policy and planning practice, with specific reference to metropolitan Cape Town, Urban Transport Research Group, Faculty of Engineering and the Built Environment, University of Cape Town

City Of Cape Town (Coct) (2005). “Nmt Policy And Strategy, Volume 2: Policy Framework”.City Of Cape Town Directorate: Transport, Cape Town.

Commission of the European Communities, 1990, Green Paper on the Urban Environment, Office of Official Publications of the EC, Luxembourg.

Greene, D. L. and Wegener, M., 1997, Sustainable transport, Journal of Transport Geography Vol. 5, No. 3, pp. 177-190

National Department Of Transport (NDoT) (2003). “National Land Transport Strategic Framework: 2006-2011”. Director General, Department Of Transport, Pretoria

Newman, P. W. G. and Kenworthy, J. R., 1989, Cities and Automobile Dependence. Gower Technical, Aldershot.

Pistorious P, 2000: Texture and Memory: The Urbanism of District Six. SUHDRU Cape Technikon, 2000

Vanderschuren, M.J.W.A., 2003, Optimising Settlement Planning in Cape Town, Paper for the International Federation of Municipal Engineers Congress, Cape Town

WCED (World Commission on Environment and Development), 1987, Our common future, Oxford University Press, Oxford.