Accessibility, Trade and Locational Behaviour

Aura Reggiani, Aura Reggiani

• Éditeur: Routledge
• Année: 2019
• ISBN:
  9780429787584
• Édition: 1
• Sujet: Business
• Sous-sujet: Foreign Exchange

First published in 1998, this timely volume features 30 specialists in civil engineering, economics, computer science, architecture, technology and infrastructure and revisits – theoretically, methodologically and empirically – the conventional concepts and measures of accessibility, and connectivity / functioning of the networks, accessibility and dynamic location effects.

1 Accessibility, Trade and Locational Behaviour: An Introduction

AURA REGGIANI

1.1 The Accessibility Concept: A Brief Review

‘Accessibility’ is a well-known term used by scientists, experts and laymen, particularly in the literature of regional and transport research where the concept of accessibility has played a major role for several decades.

This concept came to the fore in the 1950s after the rigorous legitimation of gravity theory by Isard at the First Regional Science Meeting in 1954 (for an historical review of gravity theory/spatial interaction models, see Nijkamp and Reggiani 1992). One of the first foundation stones for the use of accessibility ‘theory’ can be found in Hansen (1959), who defined accessibility as the potential of opportunities for interaction (p. 73). The quantification as well as the formulation of a theoretical structure for this concept has assumed various forms in the course of its history (Martellato et al. 1998).

Table 1.1 shows the various formal definitions of accessibility – mainly used in the regional science literature – and implicitly underlines how accessibility has been related in the past to the concepts of nearness, proximity, ease of spatial interaction, potential of opportunities for interaction, or potentiality of contacts with activities or supplies (Weibull 1980, p. 54). In other words, accessibility was considered a property of configurations of opportunities for spatial interaction (Weibull 1980, p. 53).

In this context, it is evident that, despite the various theoretical formulations displayed in Table 1.1, accessibility always emerges – in its analytical form – as the potential of opportunities:

${\text{Acc}}_{\text{i}}=\sum _{\text{j}}{\text{D}}_{\text{j}}\text{f}({\text{c}}_{\text{ij}})(1.1)$

where Acc_j defines the accessibility of some reference point (origin i), D_j is a measure (or weight) of opportunities/activities in j, and f(c_ij) is the impedance function from i to j. Consequently this interpretation of accessibility has always governed the scientific literature.

Table 1.1 Conventional measures and formulations of accessibility: a concise review

In 1979, Domanski (p. 1190) stated: ‘By accessibility I mean the possibilities of using the opportunities that the economic, social, cultural and political facilities and institutions provide.’ These opportunities may concern employment places, medical care centres, production places, shops, parks, etc., each particular type of opportunity having relevant attributes such as distance, mode of transport, travel time/cost, supply capacity, price, quality, congestion, queuing time, etc. According to model (1.1) the concept of ‘potential of opportunities’ includes a certain measurement of the opportunities at destination j, discounted (in relative or absolute value) by the spatial distance (travel/time/cost) of j from some reference point (origin) i (see again Martellato et al. 1998).

However, a closer examination of this conventional concept of accessibility shows how the concept of potential of opportunities could be better interpreted in the framework of the utility concept (the potential/expected utility of reaching (accessing) a certain place or a fixed amount of resources, or making a choice) on the basis of the fundamental works by Ben-Akiva and Lerman (1979), Domencich and McFadden (1975), and Leonardi (1978,1985) (see again Table 1.1 and Table 1.2).

It should be noted that Neuberger (1971), Williams and Senior (1978) and Wilson (1976) had already interpreted the inverse balancing factor of a spatial interaction model as an indicator of the economic benefit of facility size:

$\frac{1}{{\text{A}}_{\text{j}}}={\text{Acc}}_{\text{i}}=\sum _{\text{j}}{\text{D}}_{\text{j}}\exp (-\beta {\text{c}}_{\text{ij}})=\sum _{\text{i}}{\text{D}}_{\text{j}}\exp ({\text{u}}_{\text{ij}})(1.2)$

where

${\text{u}}_{\text{ij}}={\text{v}}_{\text{ij}}-\beta {\text{c}}_{\text{ij}}(1.3)$

represents the net gain/benefit consisting of a component V_ij (referring to the value of accessing i) minus communication costs c_ij (including also congestion/saturation costs), while β is a cost-sensitivity parameter.

In this framework the substitution of the words ‘potential utility’ for the word ‘possibilities’ in Domanski’s definition above could be the first relevant step towards bringing new perspectives to the accessibility concepts/theories/methodologies developed so far.

1.2 Accessibility and the New Space Economy

1.2.1 Introduction

In this era of globalization leading to important socio-economic and (geo)-political changes, the new position of transport/communication provokes many intriguing policy and research questions, which can roughly be interpreted under the broad umbrella of ‘transport sustainability’ (Nijkamp and Van Geenhuizen 1997; Reggiani 1997).

In this context, the new (physical and non-physical) accessibility flows and forms are coming to the fore as driving forces/trends behind globalization and the new spatial/environmental developments ranging from local to transnational scales (Van Veen-Groot et al. 1998).

It is well known that a strategic choice for reducing the economic/social/environmental/energy cost of the currently increasing mobility concerns the issue of intermodality (in both the passenger and freight transport sectors) at all levels of the transport/information organization. Intermodality – with a view to its related interoperability and interconnectivity factors – leads to what is known as the ‘Inter-transport Matrix’¹, which also raises interesting research questions regarding new concepts and approaches in transport systems analysis and modelling efforts that are able to cope with future transport/economic/spatial problems (from both the demand and supply side) (see again Reggiani 1997).

1.2.2 New Concepts in the Space Economy

One of these new approaches is the network concept, embedding not only the physical morphological structure, but also the functioning of the network itself, connecting modal points in the underlying structure with a view to efficient operations via organized linkage patterns (see Dupuy 1993).

A related question is then whether – methodologically – the network dimension is ‘captured’ by the conventional accessibility concept displayed in formulation (1.1), or alternatively, how much the functioning of the network is influenced by the new forms of accessibility (e.g. the Internet, fast modes, etc.).

Another relevant concept which has recently attracted a great deal of attention is the dynamic complexity concept and hence the related ‘complex network’ concept.

Nijkamp and Reggiani (1998) show the potential/limitations of this approach, with reference to the methodologies and empirical applications actually available in the space-economy, where the evolutionary complex forms of networks need to be predicted and evaluated. In this context, accessibility certainly plays a crucial role in both slow dynamics, characteristic of the supply side (e.g. infrastructure, facilities/locational developments), and fast dynamics, typical of the user side (e.g. demand mobility/communication patterns).

It is then clear that the conventional approach of static accessibility used so far (see Section 1.1) is a sort of ‘operational’ instrument able to ‘decodify’ the dynamic development of accessibility in the spatial complex networks.

The emerging question is whether new measures of accessibility could be able to adjust or incorporate this ‘discrepancy’ between slow and fast network dynamics (i.e. supply/demand), as well as between slow and fast spatial economic networks (e.g. different market structures in the core/periphery), for the better functioning of these interdependent networks.

Starting from the above considerations, the present volume aims to present new ‘thoughts’ and ‘reflections’ in this field, from three main perspectives: theoretical, methodological, and empirical. The next section contains an overview of the book with reference to the general theoretical background already provided in Sections 1.1 and 1.2.

1.3 New Accessibility Measures and Aspects: Theories, Methodologies and Empirical Analyses

1.3.1 Introduction

Regional Science has always been marked by a strong quantitative and model orientation. In particular, ‘Location theory makes up the heart of regional science. Both theoretically and empirically, numerous contributions have been made in this framework in order to study the “where” and the “why there” of human activities, in regard to both firms and households. Theoretically, traditional location theory a la Weber and Losch has been developed much further, by investigating spatial synergies (e.g. industrial complexes), spatial dynamics (e.g. innovation behaviour of firms, mig...