TABLE 6: COSTS FOR UPGRADING ACTIVITIES IN THE STUDY AREA

The construction costs for the activities for a paved road section on an existing road with flat terrain in the Study Area is currently estimated in table 7 [6]:

TABLE 7: COSTS COMPONENTS FOR A PAVED ROAD IN THE STUDY AREA

The road construction costs (financial costs) in the Study Area are estimated in table 8 [8]:

The road construction costs (financial costs) in the Study Area are estimated in table 8:

TABLE 8: ESTIMATED CONSTRUCTION COSTS FOR ROAD IN THE STUDY AREA

Road user costs (RUC) are defined as the costs incurred by vehicle operators and the travelling public. The road user costs are considered as the sum of:

RUC = VOC + AC + TC

3.2.1 VEHICLE OPERATING COSTS (VOC)

Economic evaluation involves the assessment of the economic worth of a project in order to ensure the optimal use of scarce economic resources. It involves the quantification of economic benefits and costs, as opposed to financial income and expenditure. Benefits are compared with costs on a marginal basis, i.e. relative to the null alternative. A project is regarded as justified if the benefits exceed the costs, regardless of who pays and who benefits.

Benefits are normally derived from a reduction in road user and maintenance costs relative to those incurred on the null alternative. Road characteristics which lead to cost and quality optimised models can be described by user related costs on a road, the "Vehicle Operating Costs" (VOC). Vehicle operating costs consist of cost components like petrol, tyre, maintenance and depreciation costs. "VOC" are a function of the riding quality of the roads on which the user travels. While the normal differences in evenness of paved roads have only a slight or even negligible effect on individual vehicles, heavy traffic loads have a considerable influence on the total sum of vehicle operating costs, a situation, which, however, is rarely encountered under Namibian traffic circumstances. The vehicle operating costs do, however, strongly increase on unpaved roads with bad riding qualities and high roughness, even for relatively small traffic numbers. It is therefore important to know the relationship between vehicle operating costs and riding quality of a road surface in order to establish a cost and quality optimised maintenance model. This relationship is changing from place to place, thus indicating its dependence on local conditions [9].

Vehicle operating costs on unpaved roads with a poor riding quality are considerable higher than on roads with good riding quality. This can be illustrated by the following example. The reported findings indicate that operating busses on the poorest class of investigated unpaved roads entails the following additional costs over and above the cost on level, paved roads:

Several studies for the establishment of "VOC" under Namibian conditions were made in the past and are summarised in tables 9 to 11 [10]:

TABLE  10   VEHICLE OPERATING COSTS FOR A PASSENGENGER CAR

TABLE  11  VEHICLE OPERATING COSTS FOR A MEDIUM TRUCK

TABLE 12 ECONOMIC VOC BY TYPE OF ROAD AND TERRAIN FOR SIX CATEGORIES IN NAMIBIA (N$/Vehkm)

Travel time have to be related to the country or the area in which a project is located. No detailed data are available for Namibia or for the Oshikoto, Ohangwena, Oshana and Omusati Regions at present. Taking data from some investigations in the SADC Region, notably RSA, the following approximate values for travelling time are given in table 13 [12]:

TABLE 13 VALUE OF TIME FOR ECONOMIC EVALUATIONS (N$/h)

The most recent study on vehicle occupancy was done for the Windhoek Eastern By-pass. Using the results for this study and applying also the results of the Ovambo Roads Master Plan studies gives the following time costs per vehicle type in table 14 [13]:

TABLE 14 TIME COSTS PER VEHICLE TYPE (N$/h)

3. ACCIDENT COSTS

No data on accident costs based on research in Namibia is available at present. The lack of reliable accident rate statistics in addition often results in low confidence in the accuracy of accident rate assessments. The most appropriate data base can be obtained from other studies in the SADC Region, notably RSA. The most recent unit costs are shown in table 15 [14]:

Accident Rates and Costs per Type of Road are shown in table 16 [15]:

TABLE 16: ACCIDENT RATES AND COSTS PER TYPE OF ROAD

The comparison of the effects on road accident rates from lane and shoulder width is pictured in table 17 [16]:

TABLE 17: ADJUSTMENT FACTORS RELATED TO LANE AND SHOULDER WIDTH

The only possible comparison with Namibian data is by dividing the number of accidents reported by the Namibian Police during 1996 by total vehicle-kilometres. The overall Road Accident Rate in Namibia for 1996 is shown in table 18 [17]:

TABLE 18: OVERALL ROAD ACCIDENT RATE IN NAMIBIA, 1996

Endnotes

[4]  Kellerhals, C,; Engelien, M.: Economic Evaluation Spreadsheet-Program, DOT, Namibia, Windhoek, Jan. 2000

[5]  Kellerhals, C,; Engelien, M.: Economic Evaluation Spreadsheet-Program, DOT, Namibia, Windhoek, Jan. 2000

[6]  Kellerhals, C,; Engelien, M.: Economic Evaluation Spreadsheet-Program, DOT, Namibia, Windhoek, Jan. 2000

[9]  Dierks, Klaus: Technical Aspects for Appropriate Low-volume Roads in Namibia, Ph.-D.-Thesis, Berlin, 1992

[10] See last endnote

[11]  Kellerhals, C,; Engelien, M.: Economic Evaluation Spreadsheet-Program, DOT, Namibia, Windhoek, Jan. 2000

[12]  Kellerhals, C,; Engelien, M.: Economic Evaluation Spreadsheet-Program, DOT, Namibia, Windhoek, Jan. 2000

[14]  Kellerhals, C,; Engelien, M.: Economic Evaluation Spreadsheet-Program, DOT, Namibia, Windhoek, Jan. 2000

[16]  See last endnote

[17]  Kellerhals, C,; Engelien, M.: Economic Evaluation Spreadsheet-Program, DOT, Namibia, Windhoek, Jan. 2000