TII Publications
DN-GEO-03060
Geometric Design of Junctions (priority junctions, direct accesses, roundabouts, grade
separated and compact grade separated junctions)
April 2017
Page 58
Figure 5.26: Treatment of Hard Shoulders at a Ghost Island Junction
5.10.2
Hard Shoulders on the Minor Road
Where the minor road has a hard shoulder, the hard shoulder approaching the major road should be
terminated by tapering to a width of 0.5m to form a hard strip. The taper angle should be 1:30 and the
taper should terminate not less than 15m before the start of the entry widening.
The hard shoulder exiting the major road should not start before the end of the exit widening.
Hard Shoulders crossing minor roads shall be terminated at the intersection of the hard shoulder and
the hardstrip/hard shoulder of the minor road corner radii or taper as appropriate.
5.10.3
Stop Line
In accordance with
the Traffic Signs Manual, the edge of the stop line nearest to the major road shall
not be closer than 0.6m to the line of the back of the paved area of the major road including any hard
shoulder or hard strip (see Figures 5.27).
TII Publications
DN-GEO-03060
Geometric Design of Junctions (priority junctions, direct accesses, roundabouts, grade
separated and compact grade separated junctions)
April 2017
Page 60
5.11.4
Permanent Crossings
On Dual Carriageways no permanent crossings of the central reserve are allowed with the exception
of single lane sections of Type 3 Dual Carriageways where a right turn off the major road may be
provided when applied for through a Departure from Standards. Right turns onto the major road are
prohibited. On Type 3 Dual Carriageways, the use of a roundabout or compact grade separated
junction close to left in/left out priority junctions for the purpose of U-turns by the diverted traffic
significantly reduces collisions.
5.11.5
Direct Vehicular Access
Direct Vehicular access from private property or developments onto Dual Carriageways should be
avoided as far as practicable. Where accesses are to be provided, their number should be severely
limited. Accesses for Dual Carriageways shall be Left-in/Left-out. For Type 3 Dual Carriageways, Left-
In / Left-Out accesses shall not be permitted within the length of a critical changeover nor within 150m
on the approach to a critical changeover as defined in DN-GEO-03031.
5.11.6
Junctions at changeover locations on Type 3 Dual Carriageways
Where junctions are provided on either the one-lane or two-lane side on a Type 3 Dual Carriageway,
they shall be restricted to left-in and left-out turning movements only, with no crossing of the central
reserve. This junction type is only suitable for lightly trafficked minor roads or private accesses. Such
junctions shall not be provided within 100m of a critical changeover as defined in DN-GEO-03031.
Where junctions of this type are required on opposite sides of the road, the side roads shall be
staggered by a nominal 10m to avoid the appearance of a through road.
Where it is necessary or desirable to provide a U-turn facility, and a roundabout is not justified, a
mainline U-turn loop can be provided at a minor road as a Departure from Standards, as illustrated in
Figure 5.28. Similar U-turn loops can be provided where there is no minor road or private access, but
it is preferable to combine a loop with a side road or access.
The preferred location for such layouts is at a changeover as defined in DN-GEO-03031. These U-
turn facilities permit right turns into the side road or access but not out and they also only allow U-
turns in one direction. Where it is assessed that minor road traffic at such a junction is likely to want
to turn right onto the major road, a similar junction shall be provided within 2km on the opposite side
of the carriageway to facilitate U-turns in the opposite direction.
Where a U-turn loop is provided at a passing lane length, the loop shall not be provided on the two-
lane side, so as to avoid the need for turning traffic to cross two through lanes.
Careful signing will be required on the approaches to all U-turn facilities (except roundabouts) to alert
drivers to the U-turn loop.