Highway Engineering

206 Highway Engineering

Example 7.2

The one-directional commercial vehicle flow data shown in Table 7.7 was col-

lected as the estimate of the opening day flow for a proposed new highway.

Solution

From the data supplied in Table 7.7, the total flow, total OGV2 flow and the

percentage OGV2 flow are as follows:

Total flow: 1440 commercial vehicles

Total OGV2 flow: 720

Percentage OGV2: 50%

Commercial Classification Number of

vehicle type vehicles

Buses/coaches PSV 80

2 axle rigid OGV1 480

3 axle rigid OGV1 70

3 axle articulated OGV1 90

4 axle rigid OGV2 220

4 axle articulated OGV2 280

5 +axle OGV2 220

Table 7.7Tr affic count

data

Traffic flow at opening (cv/d) – 1 direction

100 1000 10000 30000

1

10

100

1000

Design traffic (msa)

75%

50%

25%

100%

OGV2

Figure 7.9Design traffic for rigid, rigid composite and flexible pavement

(40-year design life) – single carriageway (HD 24/96) (DoT, 1996).