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.

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 Route 2 Route 3

Average Daily Traffic volume: Medium car: 5000 Medium Bus: 50 Heavy Truck: 1000

Average Daily Traffic volume: Medium car: 20000 Medium bus: 1000 Heavy Truck: 2000

Average Daily Traffic volume: Medium car: 10000 Medium bus: 400 Heavy Truck: 800

Existing International Roughness Index (IRI) = 10 m/km

Existing International Roughness Index(IRI) = 4.5 m/km

Existing International Roughness Index(IRI) = 7 m/km

Required overlay = 100 mm Required overlay = 60 mm Required overlay = 70 mm

Design period =3 years Design period= 3 years Design period= 3 years

Length to be overlayed= 2 km Length to be overlayed = 4 km

Length to be overlayed = 3 km

Overlay costs = RM300,000 Overlay costs= RM400,000 Overlay costs= RM 360,000

Suggest the most suitable route to be overlaid based on benefit over cost criteria.

0.000

0.200

0.400

0.600

0.800

1.000

1.200

1.400

2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0

Uni

t Roa

d U

ser C

osts

(US$

per

veh

icle

-km

)

Roughness (IRI, m/km)

Medium Car

Medium Bus

Heavy Truck

Motorcycle

Assumptions:

a. IRI after overlay will remain constant for the design period

b. Traffic volume and composition will remain constant for the design period

c. All costs in Figure 1 are in Malaysian Ringgit

d. IRI after overlay varies with thickness of overlay given by the following equation

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

0.000

0.200

0.400

0.600

0.800

1.000

1.200

1.400

2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0

Uni

t Roa

d U

ser C

osts

(US$

per

veh

icle

-km

)

Roughness (IRI, m/km)

Medium Car

Medium Bus

Heavy Truck

Motorcycle

Vehicle Type RM per vehicle-km

IRb = 10

RM per vehicle-km

IRa = 2

RM per vehicle-km

IRb - IRa

Medium car 0.24 0.205 0.04

Medium Bus 0.83 0.58 0.25

Heavy Truck 0.93 0.69 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

Unit user

cost

365 number of

year

length of

overlay

ADT RM

Medium

car

0.04 365 3 2 5000 438'000.00

Medium

Bus

0.25 365 3 2 50 27'375.00

Heavy

Truck

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

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

0.000

0.200

0.400

0.600

0.800

1.000

1.200

1.400

2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0

Uni

t Roa

d U

ser C

osts

(US$

per

veh

icle

-km

)

Roughness (IRI, m/km)

Medium Car

Medium Bus

Heavy Truck

Motorcycle

Vehicle Type RM per vehicle-km

IRb = 4.5

RM per vehicle-km

IRa = 2.355

RM per vehicle-km

IRb - IRa

Medium car 0.21 0.205 0.005

Medium Bus 0.61 0.59 0.02

Heavy Truck 0.77 0.72 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

Unit user

cost

365 number of

year

length of

overlay

ADT RM

Medium

car

0.005 365 3 4 20000 438'000.00

Medium

Bus

0.02 365 3 4 1000 87'600.00

Heavy

Truck

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

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

Vehicle Type RM per vehicle-km

IRb = 7

RM per vehicle-km

IRa = 2.355

RM per vehicle-km

IRb - IRa

Medium car 0.22 0.21 0.01

Medium Bus 0.69 0.59 0.1

Heavy Truck 0.82 0.71 0.11

0.000

0.200

0.400

0.600

0.800

1.000

1.200

1.400

2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0

Uni

t Roa

d U

ser C

osts

(US$

per

veh

icle

-km

)

Roughness (IRI, m/km)

Medium Car

Medium Bus

Heavy Truck

Motorcycle

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

Unit user

cost

365 number of

year

length of

overlay

ADT RM

Medium

car

0.01 365 3 3 10000 328'500.00

Medium

Bus

0.10 365 3 3 400 131'400.00

Heavy

Truck

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.