Highway Engineering

The Design of Highway Intersections 123

As with Example 5.1, it is decided on economic grounds to design the junc-
tion to cater for the thirtieth highest annual hourly flow. On the basis of local
traffic count data, it is found that the AAHT flow on each of the approach
roads is translated into a design peak hour flow by multiplying by a factor
of 3.0, with the results shown in Fig. 5.20.

2-lane dual carriageway

2-lane single

carriageway

15,000 to 20,000 AADT 15,000 to 20,0 00 AADT

6,000 to 8,000 AADT

N

Figure 5.18AADT flows for major and minor roads.

625 to 833 vehicles/hr

250 to 333 vehicles/hr

625 to 833 vehicles/hr

250 to 333 vehicles/hr

Figure 5.19AAHT 2-way flows.

Contd

Example 5.3 Contd

1875 to 2500 vehicles/hr

750 to 1000 vehicles/hr

1875 to 2500 vehicles/hr

750 to 1000 vehicles/hr

Figure 5.20Design peak hour flows (2-way).