World Bank Document - Africa Infrastructure Knowledge Program

308 Africa’s Transport Infrastructure
even more will have to be spent on maintenance.) Because maintenance
standards are lower under the pragmatic scenario, and because infrastructure
networks and capacity are not expanded as far, spending for maintenance
drops sharply in the pragmatic scenario but still dwarfs investment in
improvements, upgrades, and extensions of infrastructure.
The proportion of transport expenditure allocated to maintenance has
never come close to the 40 to 50 percent share shown here to be needed,
despite the establishment of road maintenance funds in many of the
countries included in this analysis. This persistent underspending on
maintenance suggests that the road networks of many countries in the
region may become unsustainable—unless a more judicious mix of
investments can be found and followed.
The Asian Development Bank (ADB 2006) estimated the road network
size that can be sustained by public sources. After reviewing current
network size and quality, as well as actual maintenance spending, the
ADB study found a negative relationship between network quality and
network replacement value as a share of GDP. When the replacement
value exceeds about 40 percent of current GDP, quality declines rapidly.
Using this finding, the study concluded that the road network density and
standards of several countries in the sample, particularly large countries
with low GDP, were greater than their economies could sustain. The foregoing
analysis supports that conclusion.
Notes
1. This chapter is based on Carruthers, Krishnamani, and Murray (2009).
2. However, the capacity of the facilities may be less than would normally be
considered acceptable for main trunk routes in an industrialized country; see
the section below on category of infrastructure.
3. The infrastructure elements included in the database are detailed in the individual
country maps appearing in the country annex to Carruthers,
Krishnamani, and Murray (2009).
4. In Uganda, no city but the capital has a population exceeding this threshold;
in Ghana, there is only one other (Kumasi). Meanwhile, in Nigeria, there are
26 and in South Africa, over 30.
5. The alternative of extending the base scenario to provide connectivity to areas
representing 80 percent of the potential value of output (that is, the value of
output if the most lucrative possible crops were grown) was also considered but
not adopted, as the cost would have been prohibitive for all countries involved.