Road Accessibility in Border Regions: a Joint Approach

Abstract

In their national contexts border areas are peripheral and generally located in sparsely populated territories, far from large urban agglomerations. Higher transport costs are therefore incurred by residents and businesses in these areas when connecting with central markets, and this reduces their accessibility to economic activities and more specialized services. Investment in transport infrastructure is a policy instrument used to lessen the remoteness of border regions and increase their accessibility. This study analyses the accessibility of the border regions of Portugal, Spain and France between 1960 and 2010. Accessibility of border regions is compared to national averages and between national and international connections. The market potential and daily accessibility indicators have been selected for this analysis using a joint approach that offers a complementary view of the changes, which occurred over this period. Given their peripheral condition, border regions are generally less accessible than the national average. However, results show that transport investments over this 50-year period helped to improve the accessibility conditions of border regions. Most interesting is the fact that many border regions have increased their accessibility levels at a higher pace than the national average, thereby reducing the accessibility gap with the rest of the country. Border regions suffer from lower accessibility to international destinations partly due to poorer network conditions. However, results show that during this period the greater changes largely benefited international accessibility. Differences between the two selected indicators offer a more complex and richer picture of the evolution of the accessibility of these border regions.

Appendices

A. Appendix 1

Fig. 4

Accumulated change in market potential (%) to national destinations

Fig. 5

Accumulated change in border regions’ market potential (%) to national and international destinations

Fig. 6

Accumulated change in daily accessibility (%) to national destinations

Fig. 7

Accumulated change in border regions’ daily accessibility (%) to national and international destinations

B. Appendix 2

In this appendix, we present the outcomes of a sensitivity analysis regarding the market potential indicator (Eq. 2) using different distance decay values α = 1.5 and α = 2. If we compare these results with the ones presented in section 5.a, we can conclude that higher distance decay values reduce the accessibility of locations, since transport costs increase (Appendix Tables 5 and 6). At the same time, changes in accessibility are lower with higher distance decay values, given that new roads built in distant locations have a lower impact on regional accessibility. However, if we look at the evolution trends, by comparing Appendix Figs. 4, 8 and 9, as well as Table 1, Appendix Tables 5 and 6 we can see that the same trend prevails. Accessibility of Portuguese and Spanish regions grew at a faster pace than the national average, regardless of the distance decay value used. In France the opposite occurs, for the reasons already given in section 5.a.

On the other hand, higher distance decay values reduce the importance of international markets to a greater extent (Table 2, Appendix Tables 7 and 8) because international destinations are generally further apart. Thus, in the Portuguese border region, international accessibility in 2010 represented more than 79% of national accessibility with α = 1, and only 3% when α = 2. Again, if we look at the evolution trend (Appendix Figs. 10 and 11), the same pattern prevails regardless of the distance decay value used. In our case, we observe a faster evolution of international accessibility when compared with national accessibility, particularly for higher distance decay values.

Table 5 Evolution of market potential to national destinations α = 1.5 (1960–2010) and accumulated change (Δ% 1960–2010). Absolute: market potential units. Relative: National average = 100%

Table 6 Evolution of market potential to national destinations α = 2 (1960–2010) and accumulated change (Δ% 1960–2010). Absolute: market potential units. Relative: National average = 100%

Fig. 8

Accumulated change (%) in market potential α = 1.5 to national destinations

Fig. 9

Accumulated change (%) in market potential α = 2 to national destinations

Table 7 Evolution of market potential in border regions α = 1.5, to national (N) and international (I) destinations and accumulated change (Δ% 1960–2010)

Table 8 Evolution of market potential in border regions α = 2, to national (N) and international (I) destinations and accumulated change (Δ% 1960–2010)

Fig. 10

Evolution of national and international market potential of border regions α = 1.5

Fig. 11

Evolution of national and international market potential of border regions α = 2