Estimating costs for a construction project many years in the future is always very uncertain. When the project is very large, complex, and likely to require years to complete, the uncertainty will be even greater. When the project is located in an area where access is difficult; supplies of materials, equipment, and skilled labor may not be adequate to ensure steady progress; and the ability of the project’s owner to maintain long-term financial and managerial commitment is unclear, uncertainties increase further.
We therefore developed only a very approximate estimate of the cost for implementing the Abuja master plan at its initial, conceptual stage. Our first report, presented in December 1977 to the Federal Capital Development Authority, included this estimate (Table 14 of that report, shown below). We envisioned Abuja at that time as a home for approximately 1.6 million people, occupying an urbanized area (including all the parks, roadways, and other infrastructure) of nearly 25,000 hectares.
Source: International Planning Associates, 1977. A New Federal Capital for Nigeria: Report No. 1, Concept Plan.