1. PAVEMENT MANAGEMENT SYSTEM
TEST NO: 1
Date: 10 Nov 2012
Question:
The Road User Costs for various types of vehicles are affected by the road roughness, as shown in
Figure 1.
Unit Road User Costs (US$ per vehicle-km)
1.400
1.200
1.000
0.800
Medium Car
Medium Bus
0.600
Heavy Truck
Motorcycle
0.400
0.200
0.000
2.0
4.0
6.0
8.0
10.0
12.0
14.0
16.0
18.0
Roughness (IRI, m/km)
FIGURE 1: RUC VERSUS ROUGHNESS
A district engineer carried out an investigation on three different routes and the results are shown in
Table 1;
TABLE 1: RESULTS OF SITE SURVEY
Route 1
Average Daily Traffic volume:
Medium car: 5000
Medium Bus: 50
Heavy Truck: 1000
Existing International Roughness
Index (IRI) = 10 m/km
Required overlay = 100 mm
Design period =3 years
Length to be overlayed= 2 km
Overlay costs = RM300,000
Route 2
Average Daily Traffic volume:
Medium car: 20000
Medium bus: 1000
Heavy Truck: 2000
Existing International
Roughness Index(IRI) = 4.5
m/km
Required overlay = 60 mm
Design period= 3 years
Length to be overlayed = 4
km
Overlay costs= RM400,000
Route 3
Average Daily Traffic volume:
Medium car: 10000
Medium bus: 400
Heavy Truck: 800
Existing International
Roughness Index(IRI) = 7
m/km
Required overlay = 70 mm
Design period= 3 years
Length to be overlayed = 3
km
Overlay costs= RM 360,000
Suggest the most suitable route to be overlaid based on benefit over cost criteria.

2. Assumptions:
a.
b.
c.
d.
IRI after overlay will remain constant for the design period
Traffic volume and composition will remain constant for the design period
All costs in Figure 1 are in Malaysian Ringgit
IRI after overlay varies with thickness of overlay given by the following equation

3. Solution:
For the Rout 1
Route 1
Average Daily Traffic volume:
Medium car: 5000
Medium Bus: 50
Heavy Truck: 1000
Existing International Roughness Index (IRI) = 10 m/km
Required overlay = 100 mm
Design period =3 years
Length to be overlayed= 2 km
Overlay costs = RM300,00
RIa= 2.0 + 0.0071 Max ( 80 – H, 0 ) Max ( RIb – 2 , 0 )
= 2 + 0.0071 Max ( 80 – 100 , 0 ) max ( 10 – 2 , 0 ) = 2
RIb = 10
Unit Road User Costs (US$ per vehicle-km)
1.400
1.200
1.000
0.800
Medium Car
Medium Bus
0.600
Heavy Truck
Motorcycle
0.400
0.200
0.000
2.0
4.0
6.0
8.0
10.0
12.0
Roughness (IRI, m/km)
14.0
16.0
18.0

4. Vehicle Type
RM per vehicle-km
IRb = 10
0.24
0.83
0.93
Medium car
Medium Bus
Heavy Truck
RM per vehicle-km
IRa = 2
0.205
0.58
0.69
RM per vehicle-km
IRb - IRa
0.04
0.25
0.24
We have unit user cost and we should find the total cost for each type of vehicle by the bellow
equation:
Vehicle type's cost = Unit user cost × 365 × number of year × length of overlay × ADT
Vehicle
type's cost
Medium
car
Medium
Bus
Heavy
Truck
Unit user
cost
0.04
365
length of
overlay
2
ADT
RM
365
number of
year
3
5000
438'000.00
0.25
365
3
2
50
27'375.00
0.24
365
3
2
1000
525'600.00
∑ 1,2,3 = 990'975.00 RM
Benefit over cost = 990'975 – 300'000 = 690'975.00 RM

5. route 2
Route 2
Average Daily Traffic volume:
Medium car: 20000
Medium Bus: 1000
Heavy Truck: 2000
Existing International Roughness Index (IRI) = 4.50 m/km
Required overlay = 60 mm
Design period =3 years
Length to be overlayed= 4 km
Overlay costs = RM400,00
RIa= 2.0 + 0.0071 Max ( 80 – H, 0 ) Max ( RIb– 2 , 0 )
= 2 + 0.0071 Max ( 80 – 60 , 0 ) max ( 4.5 – 2 , 0 ) = 2.355
RIb = 4.5
Unit Road User Costs (US$ per vehicle-km)
1.400
1.200
1.000
0.800
Medium Car
Medium Bus
0.600
Heavy Truck
Motorcycle
0.400
0.200
0.000
2.0
4.0
6.0
8.0
10.0
12.0
Roughness (IRI, m/km)
14.0
16.0
18.0

6. Vehicle Type
RM per vehicle-km
IRb = 4.5
0.21
0.61
0.77
Medium car
Medium Bus
Heavy Truck
RM per vehicle-km
IRa = 2.355
0.205
0.59
0.72
RM per vehicle-km
IRb - IRa
0.005
0.02
0.05
We have unit user cost and we should find the total cost for each type of vehicle by the bellow
equation:
Vehicle type's cost = Unit user cost × 365 × number of year × length of overlay × ADT
Vehicle
type's cost
Medium
car
Medium
Bus
Heavy
Truck
Unit user
cost
0.005
365
length of
overlay
4
ADT
RM
365
number of
year
3
20000
438'000.00
0.02
365
3
4
1000
87'600.00
0.05
365
3
4
2000
438'000.00
∑ 1,2,3 = 963'600.00 RM
benefit over cost
= 1'095'000 – 400'000 = 563'600.00 RM

7. Rout 3
Route 3
Average Daily Traffic volume:
Medium car: 10000
Medium Bus: 400
Heavy Truck: 800
Existing International Roughness Index (IRI) = 7.00 m/km
Required overlay = 70 mm
Design period =3 years
Length to be overlayed= 3 km
Overlay costs = RM 360,00
RIa = 2.0 + 0.0071 Max ( 80 – H, 0 ) Max ( RIb – 2 , 0 )
= 2 + 0.0071 Max ( 80 – 70 , 0 ) max ( 7 – 2 , 0 ) = 2.355
RIb = 7
Unit Road User Costs (US$ per vehicle-km)
1.400
1.200
1.000
0.800
Medium Car
Medium Bus
0.600
Heavy Truck
Motorcycle
0.400
0.200
0.000
2.0
4.0
6.0
8.0
10.0
12.0
14.0
16.0
18.0
Roughness (IRI, m/km)
Vehicle Type
Medium car
Medium Bus
Heavy Truck
RM per vehicle-km
IRb = 7
0.22
0.69
0.82
RM per vehicle-km
IRa = 2.355
0.21
0.59
0.71
RM per vehicle-km
IRb - IRa
0.01
0.1
0.11

8. We have unit user cost and we should find the total cost for each type of vehicle by the bellow
equation:
Vehicle type's cost = Unit user cost × 365 × number of year × length of overlay × ADT
Vehicle
type's cost
Medium
car
Medium
Bus
Heavy
Truck
Unit user
cost
0.01
365
length of
overlay
3
ADT
RM
365
number of
year
3
10000
328'500.00
0.10
365
3
3
400
131'400.00
0.11
365
3
3
800
289'080.00
Ʃ = 748'980.00
benefit over cost = 748'980 – 360'000 = 388'980.00 RM
Rout
Costs
1
690'975.00 RM
2
563'600.00 RM
3
388'980.00 RM
So, I recommend the 1st rout to be overlaid based on benefit over cost riteria.