Page 107 - Lecture Notes DCC3113

Example
Worked example

The following conditions are given:
Class of road JKR 05
Initial daily traffic volume (ADT) 6,600 bothway
Percentage of commercial vehicles 15%
Annual growth rate 7%
Equivalence factor 2.0
Subgrade CBR 5%
Rolling terrain

Initial annual commercial traffic for one way, Vo

Vo = = 6600 x 15 x 365 x 0.5 x 1
100
= 180,675

Accumulative sum of commercial traffic one way for 10 year design period

Vc = 180,675 [(1 +0.07) - 1]
10
---------------------------------
0.07
= 2.50 x 10
6

Total Equivalent Standard Axles

6
ESA = 2.0 x 2.5 x 10
= 5.0 x 10
6

Maximum Hourly One Way Traffic Flow

c = I x R x T
c = 1000 x 1.0 x 0.77 = 770 vehicles per hour

Assuming hourly capacity is ten per cent of daily capacity.

C = 7700 veh/day/lane

The estimated daily traffic Vx after 10 years is given by

Vx = 6,600 (1 + 0.07)
10
--------------------------
2
= 6490 veh/day/lane

Check C > Vx

Hence capacity has not been reached after 10 years.

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