2 Scheme Description
2.1 Scheme Overview
The location of the A68 Soutra South to Oxton road improvement scheme is shown in Figure 1, with details of the preferred scheme illustrated in Figures 2a – 2c.
The preferred scheme extends from the bottom of the Soutra South climbing lane to the north end of the three-lane section of road (differential acceleration lane or DAL) at Carfraemill Roundabout and covers a length of approximately 2.15 km. The proposed improvement consists of a new section of three-lane carriageway, with two lanes travelling southwards between bottom of the Soutra South climbing lane and the Oxton junction (C84). There is also an extension of the existing three-lane carriageway, that has two lanes travelling northwards at Carfraemill Roundabout. This will be extended through to the Oxton junction (C84).
The improvements comprise of a widened and straightened carriageway with a configuration referred to as a WS2+1. An example of a WS2+1 configuration is present at Soutra Hill and involves the presence of two lanes in one direction allowing dedicated overtaking, while traffic travelling in the opposite direction is restrained from overtaking (as identified by the characteristic red-painted central area). The scheme is designed to meet with current design standards and fulfils the objective of providing dedicated overtaking opportunities for both northbound and southbound travellers.
The southbound overtaking will be approximately 1290m in length extending from the foot of Soutra Hill (approximately 450m northwest of the existing Carfrae (D47/5) and Kirktonhill (C83) junctions) to approximately 50m southeast of Riggsyde. A changeover section of 500m in length will then be provided to allow safe access to and from the C84 Oxton road. The northbound overtaking will be extended from the existing DAL at Carfraemill Roundabout to just south east of the C84 Oxton road junction, a distance of approximately 210 m (Figure 2c).
As part of this scheme, it is necessary to close up the existing D47/5 Carfrae junction with the southbound A68, however a new access road will be provided approximately 100m to the south of the existing junction in order to maintain access to the A68. The C83 Oxton junction at this location will also require to be closed to vehicles. Access to the A68 from the west side of the road would be via a new side road linking the C83 with the C84. In order to allow continued crossing of the A68 at this point by pedestrians, cyclists and equestrians, and improve safety, an underpass will be provided between the D47/5 Carfrae and the C83 Oxton junctions.
The Annfield Bridge will remain in place to avoid severe environmental damage to the Headshaw Burn. However it will need to be widened for the additional lane requirements and the bridge will therefore be extended adjacent to the southbound carriageway.
The existing private access to Riggsyde off the A68 will be closed off and a new means of access will be provided from new side road linking the C84 and C83 (Figures 2b and 2c). The new side road will provide access to vehicles from the A68 to the D8/5 Hartside & Threeburnfold road and the D1/5 Kirktonhill road without the need to travel through Oxton village. The construction of this new side road will include a new bridge structure across the Headshaw Burn.
All of the eleven existing farm access gates along the A68 will be closed off. Alternative means of access to these fields will be gained from new and existing field gates located on side roads, which will lead to new farm access tracks.
There are no lay-bys proposed as part of the scheme therefore all the existing lay-bys are to be closed off, with the exception of the emergency lay-by, which is located immediately south of the scheme. This lay-by is to remain.
It is anticipated that on the whole, conventional construction methods will be employed for the scheme. Specific structural details, including lengths, heights and widths of cuttings and embankments, type and dimension of watercourse crossings etc. will be developed during the detailed design stage. Appropriate environmental protection measures have and will be incorporated into the scheme design, construction and operational phases.