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T.P.D.M.V.2.4
Table 4.6.8.2
Type of Merging Layout Appropriate to Flow Region
Number ( Upstream Main Line
of ( Link
Lanes { Downstream Main Line
1
2 2 2
1 2 2
2 2 3
Merging Lane Type
3 4 5 6 7
3
1
3
3
2
3
3
2
8
2 2
1 2
3 *
3
1
4
Flow
Region
A
B
C
D
E
F
G
H
I
*
*
*
*
ft
ft
ft ft ft ft
ft ft ft ft
* «
* ft
ft ft ft
ft ft ft
4*6.8.11 The merging lane types are shown in Diagram Nos. 4*6.8.1, 2, 3
and 4 and the following notes on each type should also be
considered in deciding upon the appropriate layout.
4.6*8.12 Types 1 * 4 (Diagram No. 4.6,8.1)
The direct entry is the most economical merging layout for
single lane links* It will cater for entry flows up to
approximately 1000 v.p.h. after correction, but should only be
used under favourable site conditions. Hhere the main line is
situated on a left hand curve, where the main line is on a
gradient or where for other reasons it is necessary to provide
greater definition of the merging lane, the more generous
parallel type merging lane layout should be adopted.
4.6.8.13 Types 2 + 5 (Diagram No. 4.6.8.2)
The direct entry layout is suitable for the higher entry flows
near the limit of a single lane entry but where diverse
geometric conditions render a single lane entry unsuitable. The
shadow island merging layout is the more normal and preferred
layout where entry flows dictate a two lane entry and where
there is not the need for the addition of an extra lane