3.0 DETERMINATION OF TRANSPORT COSTS

 

The Road Authority is legally funded by the Road Fund Administration. The Road Fund Administration is expecting to get an optimum value for its financial input to the Road Authority. This means that in the normal case the Road Fund Administration only funds the financial costs and not the economic costs. It has to be argued that the difference between financial and economic costs (D x) has to be financed by Vote of Parliament and not the Road Fund Administration if it cannot be proven that D x is the most efficient way executing the job.

In this Study the economic evaluation is based on the annual road owner costs and road user costs generated. In order to distinguish between financial and economic costs conversion factors (shadow pricing) are used as shown in table 4 [4]:

 

TABLE 4: CONVERSION FACTORS BETWEEN FINANCIAL AND ECONOMIC TRANSPORT COSTS

 

Works

Factor

Maintenance works on gravel roads

0,86

Maintenance works on paved roads

0,82

Road construction

0,73

Labour based works

0,55

 

3.1 ROAD OWNER COSTS

 

3.1.1 MAINTENANCE COSTS

 

The annual cost of road works is calculated from the amount of routine maintenance, periodic maintenance and any other road improvements carried out in the given year in the Oshikoto, Ohangwena, Oshana and Omusati Regions and are shown in table 5 [5]:

 

TABLE 5: COSTS FOR MAINTENANCE ACTIVITIES IN THE STUDY AREA

 

Earth Roads

Gravel Roads

Surface Dressing

Asphalt Concrete

(hot Mix)

Routine Maintenance

 

 

 

 

 

 

 

 

Usually labour based activities, employing local people:
bulletSpot regravelling
bulletBlading
bulletClearing drains
bulletVerge clearing
bulletRoad furniture maintenance
bulletSpot regravelling
bulletBlading
bulletPatching
bulletCrack Sealing
bulletPatching
bulletCrack Sealing
Routine Maintenance

Costs N$/km/Year

Approx. 400 – 600 N$/km

Approx. 2 500 – 5000 N$/km

(Average: 3 900 N$/km Financial Unit Costs and

3 354 N$/km Economic Unit Costs)

Approx. N$ 4878

(Financial Costs)

Approx. 4 000 N$/km

(Economic Costs)

Approx. N$ 4878

(Financial Costs)

Approx. 4 000 N$/km

(Economic Costs)

  Earth Roads Gravel Roads Surface Dressing  

Asphalt Concrete

(hot Mix)

Periodic Maintenance

 

 

 

 

 

 

 

 

 

 

Costs N$/km

In general no periodic maintenance

Regravelling:

5 to 50 years

bulletRejuvenation

Spray

Every 3 Years

bulletSlurry Spray

Every 10 Years

bulletSurface Dressing
bulletSurface Seal
bulletReseal

Every 9 to 20 years

bulletRejuvenation

Spray

Every 3 Years

bulletSlurry Spray

Every 10 Years

bulletSurface Dressing
bulletSurface Seal
bulletReseal

Every 9 to 20 years

-

Approx. 90 000 N$/km

(Financial Unit Costs)

Approx. 77 400

N$/km

(Economic Unit Costs)

Rejuvenation:

Approx. 18 000

N$/km

(Financial Unit Costs)

Approx. 14 760

N$/km

(Economic Unit Costs)

Slurry Spray:

Approx. 125 854

N$/km

(Financial Costs)

Approx. 103 200

N$/km

(Economic Costs)

Reseal:

Approx. 84 000 N$/km

(Financial Unit Costs)

Approx. 69 880

N$/km

(Economic Unit Costs)

Rejuvenation:

Approx. 18 000

N$/km

(Financial Unit Costs)

Approx. 14 760

N$/km

(Economic Unit Costs)

Slurry Spray:

Approx. N$ 125 854

(Financial Costs)

Approx. N$ 103 200

(Economic Costs)

Reseal:

Approx. 84 000 N$/km

(Financial Unit Costs)

Approx. 69 880

N$/km

(Economic Unit Costs)

 

TABLE 6: COSTS FOR UPGRADING ACTIVITIES IN THE STUDY AREA

 

Upgrading Improve geometric and structural standards Improve geometric and structural standards Improve geometric standards
Investment, Works 150 – 200 mm gravel

Drainage

Culverts

Bridges

Regravelling 150 – 200 mm

Surface Dressing

Culverts

Bridges

Regravelling 150 – 200 mm

30 – 50 mm hot mix asphalt concrete

Costs (financial) N$/km Approx. 240000,- Approx. 760000,- Approx. 800000,-

 

 

3.1.2 CONSTRUCTION COSTS

 

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

 

Activities

N$/km

Double Surface Dressing

130 000

200 mm Gravel Base Layer (10,000 m x 0,2 x 120)

240 000

Subbase

90 000

Drainage Structures

220 000

Project and Construction Control

80 000

TOTAL

760 000 [8]

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

 

TYPE OF ROAD

FINANCIAL COSTS (N$/km)

Earth Road

50 000

 

Gravel

Min. 136 000

Max. 461 000

Aver. 289 000

230 000 (Class A (10 m))

180 000 (Class B (7,5 m))

Surfaced Road

Double Surface Dressing

Min. 55 000

Max. 1 172 000

Aver. 719 000

760 000

 

3.2 ROAD USER COSTS

 

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:

 

bulletVehicle Operating Costs (VOC)
bulletTravel Time Costs (TC) and
bulletAccident Costs (AC)

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:

bullet

Petrol: increases by 20%, depending on speed and topography;

bullet

Tyres: increases by 100%, depending on the type of gravel;

bullet

Maintenance: increases by 40%, depending on vehicle age;

bullet

Total: increases by 40%.

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  9  VEHICLE OPERATING COSTS FOR A PASSENGER BUS

 

|==================================================================|
|  ROAD   | SURFACE | VEHICLE OPERATING COSTS IN US CENT PER KM    |
|ROUGHNESS| TEXTURE |----------------------------------------------|
|  IRI    |         | TYRE |MAINTENANCE|DEPRECIATION| FUEL | TOTAL |
|         |         |      |    LABOUR | INTEREST   |      |       |
|---------|---------|------|-----------|------------|------|-------|
|  1,50   |    P    |  2,8 |     7,0   |    9,4     | 14,6 |  33,8 |
|  2,00   |    P    |  3,1 |     7,8   |    9,7     | 15,3 |  35,9 |
|  3,00   |    P    |  3,5 |     9,1   |   10,5     | 15,4 |  38.5 |
|  3,50   |    P    |  3,9 |     9,8   |   10,9     | 15,5 |  40,1 |
|  4,25   |    P    |  4,3 |    10,5   |   11,4     | 15,6 |  41,8 |
|  5,00   |   UP    |  4,7 |    11,4   |   11,7     | 15,9 |  43,7 |
|  5,75   |   UP    |  5,1 |    12,1   |   12,2     | 16,0 |  45,4 |
|  6,50   |   UP    |  5,5 |    13,3   |   12,5     | 16,2 |  47,5 |
|  7,00   |   UP    |  5,9 |    14,1   |   12,9     | 16,4 |  49,3 |
|  7,50   |   UP    |  6,2 |    14,5   |   13,3     | 16,6 |  50,6 |
|  8,40   |   UP    |  6,7 |    16,0   |   13,7     | 16,7 |  53,1 |
|  9,00   |   UP    |  7,0 |    16,8   |   14,1     | 16,9 |  54,8 |
|  9,75   |   UP    |  7,8 |    17,2   |   14,5     | 17,0 |  56,5 |
| 10,50   |   UP    |  8,2 |    17,6   |   14,8     | 17,2 |   57,8|
|==================================================================|
NOTA: Tables 25 to 27: Data are recalculated and adapted to
Namibian road conditions for the price level of December 1989
(1 US $=R 2,63). P = Paved Roads; UP = Unpaved Roads. Original
data of the Natal/Kwazulu Study were established for the year 1986. Prices have been established without taxes and subsidies.

 

TABLE  10   VEHICLE OPERATING COSTS FOR A PASSENGENGER CAR

 

|==================================================================|
|   ROAD  | SURFACE | VEHICLE OPERATING COSTS IN US CENT PER KM    |
|ROUGHNESS| TEXTURE |----------------------------------------------|
|   IRI   |         | TYRE |MAINTENANCE|DEPRECIATION| FUEL | TOTAL |
|         |         |      |    LABOUR |  INTEREST  |      |       |
|---------|---------|------|-----------|------------|------|-------|
|   1,50  |    P    | 0,30 |    1,57   |     5,03   | 3,52 |  10,4 |
|   2,00  |    P    | 0,44 |    1,95   |     5,82   | 3,55 |  11,8 |
|   3,00  |    P    | 0,47 |    2,30   |     5,94   | 3,59 |  12,3 |
|   3,50  |    P    | 0,57 |    2,65   |     6,32   | 3,62 |  13,2 |
|   4,25  |    P    | 0,65 |    3,04   |     6,77   | 3,67 |  14,1 |
|   5,00  |   UP    | 0,68 |    3,41   |     7,22   | 3,71 |  15,0 |
|   5,75  |   UP    | 0,74 |    3,78   |     7,72   | 3,80 |  16,0 |
|   6,50  |   UP    | 0,82 |    4,12   |     8,23   | 3,87 |  17,0 |
|   7,00  |   UP    | 0,87 |    4,53   |     8,64   | 4,01 |  18,0 |
|   7,50  |   UP    | 0,96 |    4,97   |     9,16   | 4,03 |  19,1 |
|   8,40  |   UP    | 1,04 |    5,26   |    10,11   | 4,08 |  20,5 |
|   9,00  |   UP    | 1,10 |    5,65   |    10,79   | 4,18 |  21,7 |
|   9,75  |   UP    | 1,17 |    5,90   |    11,70   | 4,26 |  23,0 |
|  10,50  |   UP    | 1,21 |    6,30   |    12,57   | 4,29 |  24,4 |
|  11,00  |   UP    | 1,26 |    6,64   |    13,48   | 4,40 |  25,8 |
|==================================================================|

 

TABLE  11  VEHICLE OPERATING COSTS FOR A MEDIUM TRUCK

 

|==================================================================|
|   ROAD  | SURFACE | VEHICLE OPERATING COSTS IN US CENT PER KM    |
|ROUGHNESS| TEXTURE |----------------------------------------------|
|   IRI   |         | TYRE |MAINTENANCE|DEPRECIATION| FUEL | TOTAL |
|         |         |      |   LABOUR  |   INTEREST |      |       |
|---------|---------|------|-----------|------------|------|-------|
|   1,50  |     P   |  3,1 |    17,1   |    14,0    |  9,3 |  43,5 |
|   2,00  |     P   |  3,5 |    17,9   |    14,4    | 10,1 |  45,9 |
|   3,00  |     P   |  3,9 |    18,7   |    15,0    | 10,6 |  48,2 |
|   3,50  |     P   |  4,1 |    19,1   |    15,4    | 11,1 |  49,7 |
|   4,25  |     P   |  4,3 |    19,8   |    15,8    | 11,8 |  51,7 |
|   5,00  |    UP   |  4,7 |    20,3   |    16,1    | 12,2 |  53,3 |
|   5,75  |    UP   |  5,0 |    20,8   |    16,6    | 12,9 |  55,3 |
|   6,50  |    UP   |  5,3 |    21,4   |    17,1    | 13,6 |  57,4 |
|   7,00  |    UP   |  5,7 |    22,0   |    17,3    | 14,0 |  59,0 |
|   7,50  |    UP   |  6,1 |    22,9   |    18,0    | 14,7 |  61,7 |
|   8,40  |    UP   |  6,5 |    23,3   |    18,4    | 15,2 |  63,4 |
|   9,00  |    UP   |  6,8 |    23,9   |    18,8    | 15,8 |  65,3 |
|   9,75  |    UP   |  7,4 |    24,5   |    19,4    | 16,4 |  67,7 |
|  10,50  |    UP   |  7,8 |    25,2   |    20,0    | 17,0 |  70,0 |
|  11,00  |    UP   |  8,2 |    25,7   |    20,5    | 17,6 |  72,0 |
|==================================================================|

Table 9 shows between the two extreme roughness relationships a maximum increase in total vehicle operating costs of 71% from a very smooth paved road with IRI=1,50 to a very rough unpaved road with IRI=10,50. The same relationships will be developed also for a passenger car in table 10 (increase in total "VOC" = 147% for a riding quality difference between IRI=1,50 and IRI=11,00) and for a medium truck in table 11 (increase in total "VOC" = 65% for a riding quality difference between IRI=1,50 and IRI=11,00) adapted to Namibian conditions (all for rolling terrain).

The tendencies in above tables are confirmed in recent Namibian investigations for the year 1998 and are summarised in table 12 [11]:

 

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

 

Vehicle Type/

Surface Type/

Roughness IRI

Flat

Tangent and Rolling (TR)

Flat and Winding (FW) Rolling

Mountainous

SMALL CAR

Bitumen (B) 2,00

0,787

See Flat

See Flat

See Flat

0,845

B 4,00

0,858

See Flat

See Flat

See Flat

0,914

Gravel (G) 6,00

0,980

See Flat

See Flat

See Flat

1,074

G 8,00

1,132

See Flat

See Flat

See Flat

1,194

G 12,00

1,620

See Flat

See Flat

See Flat

1,680

UTILITY CAR

B 2,00

0,915

See Flat

See Flat

See Flat

1,009

B 4,00

0,998

See Flat

See Flat

See Flat

1,091

G 6,00

1,149

See Flat

See Flat

See Flat

1,269

G 8,00

1,347

See Flat

See Flat

See Flat

1,480

G 12,00

1,976

See Flat

See Flat

See Flat

2,054

MINIBUS

B 2,00

1,059

See Flat

See Flat

See Flat

1,108

B 4,00

1,154

See Flat

See Flat

See Flat

1,204

G 6,00

1,290

See Flat

See Flat

See Flat

1,378

G 8,00

1,512

See Flat

See Flat

See Flat

1,630

G 12,00

2,110

See Flat

See Flat

See Flat

2,232

BBUS

B 2,00

2,596

2,729

See TR

See TR

4,180

B 4,00

2,783

2,923

See TR

See TR

4,410

G 6,00

3,025

3,199

See TR

See TR

4,729

G 8,00

3,406

3,612

See TR

See TR

5,292

G 12,00

4,542

4,768

See TR

See TR

6,372

MEDIUM TRUCK

B 2,00

1,776

See Flat

See Flat

See Flat

2,440

B 4,00

2,118

See Flat

See Flat

See Flat

2,790

G 6,00

2,475

See Flat

See Flat

See Flat

3,193

G 8,00

2,918

See Flat

See Flat

See Flat

3,520

G 12,00

3,969

See Flat

See Flat

See Flat

4,208

HEAVY TRUCK

B 2,00

3,278

See Rolling

See Flat

4,042

7,205

B 4,00

3,836

See Rolling

See Flat

4,613

7,853

G 6,00

4,420

See Rolling

See Flat

5,252

8,553

G 8,00

5,106

See Rolling

See Flat

5,943

9,261

G 12,00

6,746

See Rolling

See Flat

7,453

N/A.

 

3.2.2 TRAVEL TIME COSTS

 

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)

 

Description Value of Time (N$ per hour)
Workers - High Income

                - Medium Income

                -Low Income

Non-Workers or Leisure Time

54

16

3

2

 

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)

 

Vehicle Type

Vehicle Occupancy

Time Cost (N$ per hour)

Small Car

Utility Car

Minibus

Bus

Medium Goods Vehicle

Heavy Goods Vehicle

2,5

3,7

6,0

27

3,8

2,0

19,30

19,90

20,80

92,20

17,50

25,90

Aggregated Cost on Trunk Roads

As above

22,43

Aggregated Cost on Main and District Roads

As above

20,41

 

 

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]:

 

TABLE 15 ACCIDENT UNIT COSTS (N$ PER ACCIDENT)

 

 

ACCIDENT TYPE

  Fatal Serious Injury Slight Injury Damage only Average
Average Cost per Accident

247 764

64 954

18 494

13 076

21 228

 

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

 

TABLE 16: ACCIDENT RATES AND COSTS PER TYPE OF ROAD

 

Road Type
Gravel Two-lane paved Freeway
Accident Rate

(per million vehicle km)

2,29

0,99

0,27

Composition (%)
bulletFatal
bulletSerious Injury
bulletSlight Injury
bulletDamage only


10,9
6,5
10,9
71,7


7,8
9,5
17,7
65,0


3,2
4,2
19,6
73,0

Costs (N$ per accident)

42 587

37 246

23 817

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

 

Lane width in metres Adjustment Factor (F) Shoulder width in metres Surfaced Shoulder (F) Unsurfaced Shoulder (F)

2,74

3,06

3,35

3,66

1,18

1,04

1,00

1,00

0,00

1,07

1,68

2,29

2,90

1,57

1,29

1,14

1,02

1,00

1,57

1,40

1,30

1,23

1,20

 

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

 

  No. of Accidents

All Roads

Vehicle-Kilometres

Millions 1996797

Accident Rate

Per Million Vehicle-

Kilometres

No. of Collisions

6 225

2 783,65

2,23

Fatalities

182

   
Serious Injuries

437

   
Slight Injuries

703

   

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

[7]  Roads Authority of Namibia in co-operation with Technische Universitšt Berlin: Economically Justified Maintenance on Unpaved Roads in Namibia, Berlin, 2001

[8]  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

[13]  See above endnote

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

[15]  See last endnote

[16]  See last endnote

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

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