By Eng. Isaac Mutenyo (PhD)
There has been continued reference to the large disparity in what many people refer to as the unit cost of roads or the cost per kilometer (km).
The common observation referred to is that the unit cost of a road varies so much within and between government projects and that generally the unit cost of a road in Uganda is higher compared to other countries in the East Africa region and on the African continent.
The question has therefore been: “What is the unit cost of a road in Uganda?”. No straight answer has been given by any engineer or authority to this question but rather a wide range of costs per km for different roads have been shared. To justify the wide range, engineers have laboured to explain the cost elements and the difficulty and misrepresentation of quoting a unit cost of a road for a country based on the length as a unit.
The difficulty is because, although ,one of the standard measures or unit of a road is the length (km), you cannot simply use it as the only unit to determine the standard unit cost of a road. This explanation has been given by MoWT, UNRA, USMID, KCCA and many other agencies involved in road construction.
This explanation has however, been received with infuriation by those who seek answers and as a result they have continuously resorted to simply diving the total cost of road works done by the length of the road to determine the unit cost. This derived cost per km is then what is used as the unit cost of a road for comparison between different road projects and countries. This is utterly misleading and provides no useful information for planning, budgeting or determination of value for money.
Unit costs are a useful statistic for comparison purposes and for planning to guiding future developments. For fair and meaningful comparison, the parameters being compared must be alike and it is the likeness that determines the definition of a unit.
For road works, it is unlikely that you can have the same elements and environmental conditions of a road covering the entire km of each road in a country or region. However, there are elements of a road that are key cost drivers in road construction that determine the intrinsic cost of a road.
Such elements include drainage channels, pavement layers (depth and width), walkways, relocation of service utility lines, street lighting, ground works, concrete structures, etc. Using the unit cost of these can be a better means of comparing unit costs for roadworks across the country and projects.
In fact, it is the relative quantities of these elements that largely determine the overall cost of a road. The final cost of a road project will depend on how much of these elements are required in each sectional width and length of the road.
A recent unit cost analysis carried out for road construction under the USMID program revealed that for urban road construction, the key cost drivers include: drainage works (average 47% of total contract cost); earthworks and pavements layers of gravel and crushed stones (average 17% of total contract cost); Asphalt pavements and seals (average 12% of total contract cost).
A comparison of the share of the cost of these elements with other projects gives a fair result. For Mpigi town roads drainage works accounts for 48% of total contract value, while earthworks and pavement layers of gravel and crushed stones accounts for about 17%.
The cost distribution for national roads and highways may be different since earthworks seem to account for a higher cost due to the requirement to meet geometrical standards for long sections and drains are not normally covered like in urban roads. Other additional cost centres which are common for urban road works are compensations for encumbered road sections; the relocation of utilities (water lines, electricity lines, telecom lines, security installations, etc.) that are common in built up areas such as cities and municipalities.
Utility relocation costs account for an average of 5% and in some cities goes up to 10% of the contract value. Determination of unit cost for comparison purposes and for planning for future developments is better done using these high-cost road elements rather than cost per km.
How to get it right
Roads are designed considering the required service level or purpose; the environment and ground conditions in which the road is located, the socio-economic conditions of the location, the available budget, the standards and specification which provide the design criteria. For instance, a road constructed in the centre of a city has requirements that are different from that in a rural area.
Similarly, a road that is constructed in a swampy ground in an area has different consideration from another road constructed in firm ground within the same area. The considerations for design, cost estimation and construction include method of work, period of construction, structural elements to be provided for, acquisition of right of way, relocation of utility lines, street lighting, environment and social safeguards, etc. and therefore the eventual unit cost cannot be the same.
However, the unit cost of the different elements could be the same but because those elements are required in different quantities, the construction costs can vary considerably even within the same region.
It is therefore, important that whoever is involved in monitoring and wishes to make plausible comparisons to determine service delivery and value for money takes a deeper look into the underlying causes of cost variations rather than simply using the cost per kilometer.
The writer is the Chairman Engineers Registration Board and USMID-AF Project Coordinator
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