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T.P.D.M.V.2.4
4*3»10 Left TurningLanes (Diverging)
4.3.10.1 Nearside diverging lanes allow left .turning major road traffic
to slow down and leave the major road without impeding the
following through traffic. They should be formed by a taper to
a width of 3,5m contiguous to the corner into the minor road
which should preferably be of radius 20m. The width of entry to
the minor road will depend on this radius.
A typical layout is illustrated in Diagram No. 4.3.16.4.
4.3.10.2 Nearside diverging lanes should not be provided at simple
priority junctions but should be provided at other priority
junction types where the following conditions are met :
(a) Design speed 80 km/h or above and left turning
greater than 600 vehicles AADT.
traffic
(b) Design speed 80 km/h or above and left turning traffic
greater than 450 vehicles AADT with at least 20* heavy
goods vehicles.
(c) At any design speed where gradient is greater than 4 and
left turning traffic greater than 450 vehicles AADT.
However they should not be provided where the minor road is on
the inside of a sharp curve as traffic on the diverging lane
could adversely affect visibility for drivers emerging from the
minor road.
4.3.10.3 The length of nearside diverging lane is defined as being from
the beginning of the taper to the point of conflict with the
major road right turning traffic. For design speeds of 70 km/h
or less the length should be 35m. For design speeds greater
than 70 km/h maximum and minimum lengths of diverging lane
should be in accordance with Table 4.3*10.1.
Table 4.3*10*1
Maximum and (Minimum) Lengths of Nearside Diverging Lane
Design Speed
(km/h)
100A
85A
Up Gradient
0 - 4* Above 4*
80(40}
55(35)
55(35)
40(35)
80(40)
55(35)
Down Gradient
Above 4)1
(a) (b)
80(40) 110(55)
55(35) 80(40)
(a) a shadow and physical island single carriageway sites.
(b) s dual carriageway sites.