11 Vehicle Travellers 11.1 Scope of the Assessment 11.2 Statutory and Planning Context 11.3 Assessment Methodology 11.4 Baseline Conditions 11.5 Impacts of the Proposed Scheme 11.6 Mitigation and Monitoring 11.7 Residual Effects
11 Vehicle Travellers
11.0.1 This chapter reports the findings of the assessment of the predicted impacts on vehicle travellers (vehicle road users). The assessment considers two aspects; driver stress and view from the road.
11.1 Scope of the Assessment
11.1.1 The Proposed Scheme comprises part of a broader strategy for upgrading the A75 as the principal route to the important ferry terminals at Stranraer and Cairnryan (see Section 1.0). The trunk road is also an important route for tourists seeking access to the south west of Scotland. Conflicts between strategic, tourist and local traffic are an everyday occurrence (see Section 2.1.4). Restricted opportunities for overtaking induce risk, which contributes to high levels of stress.
Driver Stress
11.1.2 The guidelines refer to a number of ways in which development of the type proposed can influence driver stress.
- Route uncertainty - caused by a lack of, or inadequate signing.
- Fear of potential accidents - caused by the presence of other vehicles and inadequate sight distances.
- Frustration - caused by a driver's inability to drive at a speed consistent with his or her own wishes in relation to the general standard of the road. This may be a result of road layout, geometry, surface riding characteristics, junction frequency and speed and flow per lane.
View from the Road
11.1.3 There are a number of ways in which development can have an adverse or beneficial effect on views from the road.
- They can change the extent and availability of the traveller’s view, which is dictated by the relative level of the road and the surrounding landform, buildings, vegetation, associated structures and environmental barriers.
- They can enhance or detract from the travellers experience by the removal of existing features, such as mature trees and distinctive townscape elements or derelict buildings and existing eyesores.
- They can introduce new features and landscape/townscape to the benefit of the traveller’s experience.
11.2 Statutory and Planning Context
11.2.1 There are no statutory or planning-specific guidelines related to driver stress or the view from the road; however there is a strong correlation to elements of the landscape character, which are appraised in Chapter 8. Safe and stress-free travel opportunities are, however, integral to transport policy and the design standards adopted by Transport Scotland in their capacity as the agency responsible for the national trunk road network.
11.3 Assessment Methodology
11.3.1 The assessment has been undertaken in accordance with the methods outlined in the Volume 11, Section 3, Part 9 of the DMRB.
Driver Stress
11.3.2 The assessment of driver stress is based on the traffic and road conditions encountered and driver certainty. The following factors have been considered: traffic flows; journey speed; frustration; fear; and uncertainty.
11.3.3 In relation to traffic flows and journey speed, the DMRB provides guidance relating levels of driver stress to the average hourly flow per lane, average journey speed, the urban or rural location of the road, and taking account of the type of road (motorway, dual carriageway or single carriageway).
11.3.4 It is realised that environmental assessments, providing the speeds and flows exist during peak hour flows for at least one kilometre of a route the following figures presented in Table 11.1 can be used. The DMRB assessment also requires an assessment to be made between the ‘do-nothing’ and ‘do-something’ options. In this regard the scheme switches from a single-carriageway to a widened single-carriageway with alternating overtaking sections. The assessment is made for the worst year in the first fifteen after opening.
Table 11.1 – Stress ratings for single carriageway roads
Average peak hourly flow per lane25, |
Average Journey Speed – km/hr |
||
|---|---|---|---|
Under 50 |
50 – 70 |
Over 70 |
|
Under 600 |
High |
Moderate |
Low |
600 - 800 |
High |
Moderate |
Moderate |
Over 800 |
High |
High |
High |
N.B. A car or light van equals 1 flow unit. A commercial vehicle over 1.5 tons unladen weight or a public service vehicle equals 3 flow units.
View from the Road
11.3.5 The assessment of views from the road has considered those aspects discussed in Paragraph 11.1.3. Views have been categorised as follows:
- No view –where the road is in deep cutting or contained by earth bunds, environmental barriers or adjacent structures.
- Restricted view – frequent cutting or structures would block the view.
- Intermittent view – the road would generally be at ground level but with shallow cuttings or barriers at intervals.
- Open view – an unobstructed view.
11.3.6 Impacts have been evaluated based on a comparison of the views for travellers using the existing road compared with travellers who would use the proposed road. Changes in the extent, availability and nature of the views have been quantified in terms of the length of affected road.
11.3.7 The assessment concludes with a statement of the order of impact, assuming the proposed road to be operational and that proposed landscape measures have been established for 15 years (the design year). The order of impact is based on a three point scale of better/neutral/ worse.
11.4 Baseline Conditions
View from the Road
11.4.1 Driver views along the existing section of the A75 comprise a mixture of open vistas across farmland and restricted views due to the presence of plantation woodland adjacent to the carriageway. Driving east from the Carrutherstown there are views to the north of the village of Carrutherstown and to the south over agricultural fields in the vicinity of Fostermeadow Farm. From Whitecroft Gate, on the eastern periphery of the village where the route moves gently south-eastwards, Braemoss Wood, adjacent to the south of the carriageway, obscures views for approximately 0.5 km. To the north are extensive views of the rolling agricultural landscape. At this point where the straight road alignment provides views ahead to Kiln Knowe where the road gently rises.
11.4.2 From Kiln Knowe to the U81a and beyond, to the western edge of Braehill Oak Wood, there are extensive views of arable and rough grazing farmland both north and south over the undulating topography. As the existing alignment is fairly straight there are clear views ahead to the brow of the hill approximately at Oakbank. Whilst open views are generally retained to the south, with the exception of a small cluster of mature trees at Popin Well, views to the north around Oakbank are obscured by Braehill Oak Wood for approximately 0.2 km.
11.4.3 From Oakbank east to Stenriesgate there are generally open views of the agricultural landscape, with hedgerow field boundaries in the north. There are occasional clusters of trees and scrub along the southern edge of the carriageway. Despite the relatively straight alignment of the route, accesses, including the U81a road junction, are not clear from a distance and obscured from view by the presence of small hedges running parallel with the northern verge.
11.4.4 Views of the route ahead (looking east) are possible along the existing alignment from Oakbank to Stenriesgate and possibly beyond. Approximately 0.2 km east of Stenriesgate, views to the north are totally obscured to the end of the route section under consideration i.e. to Upper Mains access road. This is due to the presence of woodland, namely, Kelhead Moss Plantation, which form a continuous curtain. Whilst views to the north are obscured over this section of the route, in contrast, to the south unbroken views over farmland to Topmuir Farm are observed. From approximately Stenries View access road, where the land raises slightly, the remainder of the route ahead to Upper Mains is visible.
Driver Stress
11.4.5 The current A75 comprise a single carriageway over the 3.6 km section covered by the Proposed Scheme (see Figure 2.1). Accordingly, the average predicted two-way peak hourly flows are calculated at 1013 with a 19.7% HGV split and a speed of 75 kph. The flow unit per lane is correspondingly 706 (see footnote26). The level of driver stress is therefore assessed as being ‘moderate’ under the worst-case do-nothing scenario.
11.4.6 Slow moving farm vehicles, lorry convoys and tourist traffic coupled with restricted overtaking opportunities and concealed junctions/property entrances are features of this route that may result in driver frustration, fear and uncertainty.
11.5 Impacts of the Proposed Scheme
View from the Road
11.5.1 On the whole, the scheme is not anticipated to significantly affect vehicle-travellers view’s as it runs adjacent to the south of the existing A75. The most apparent change to driver views relate to where cuttings and embankments are proposed and where mounding is proposed. A cutting of less than 100 m in length in the vicinity of Whitecroft Gate will result in a lowering of the new carriageway, by a maximum of 2.5 m below the existing ground level. A similar situation will arise at Kiln Knowe where the route will be confined to a cutting for an approximate distance of 150 m and, at its maximum, 2.5 m below the existing ground level. A further cutting of approximately 200 m in length will begin at Popin Well Wood where the maximum height difference between existing levels and the new carriageway will be approximately 4.6 m. In addition; the construction of an embankment at Hardgrove to accommodate the proposed underpass will see the new carriageway raised some 7 m above the existing ground surface. Finally, excess fill will be mounded. This will be used between the new and existing A75 between Chainage 500–1100 and 1500–3100 creating a relative mound height of between 1.0 to 2.5 m at its apex.
11.5.2 The proposed realignment of the A75 and the anticipated vegetation clearance required to facilitate the progression of the carriageway will provide vehicle-travellers with greater open views of the wider landscape. Utilising DMRB criteria, views from the road for the existing and the proposed realignment are considered to be of moderate importance to vehicle travellers.
11.5.3 Views from the road experienced by vehicle-travellers are anticipated to change with the realignment of U81a and the associated underpass at Hardgrove. The biggest change will be to the fore-ground views where vegetation is cleared; once the vegetation has established the views from the road shall be similar to pre-construction of the alignment.
11.5.4 The new side road links to the existing A75 from the B725 at Carrutherstown, and from the proposed new A75 carriageway at Stenries, will result in temporary scarring whilst the proposed access to Fostermeadow will follow an existing track that will minimise visual impacts.
11.5.5 The Proposed Scheme will alter the driver views. The planting and mounding proposed along large sections to the north of the new alignment will provide a clear distinction between the characteristics and views experienced along the retained section of the A75 offset that of the new trunk road. Principally, views to the north from the new alignment will be intermittent and restricted given its slightly higher elevation around the U81a, whilst those views to the south with remain consistent with the current situation. Equally, views to the south from the retained section of the A75 will become restricted over a large section of the route whilst views to the north are maintained. Overall however, the generated views are consistent with the remainder of the A75 and are therefore assessed as negligible and not significant.
Driver Stress
11.5.6 Most modern road improvements designed in accordance with current standards are normally classified as inducing moderate-to-low levels of driver stress (DMRB Volume 11, Section 3, Part 9, Chapter 4).
11.5.7 The Proposed Scheme comprises an offline alignment with the provision of structured overtaking opportunities and rationalisation of existing accesses; including development of safer offline arrangements. The scheme’s aim is to provide coherent and structured opportunities for access and egress to and from the A75 from properties in conjunction with safe and clear overtaking opportunities. Meeting these aims will reduce driver frustration and fear of accidents as well as uncertainty in relation to the route being followed.
11.5.8 Despite the scheme proving a residual level of moderate driver stress, which as highlighted in Paragraph 11.5.7, is common to roads of this nature and design, the third-lane and improved access to and from the A75 will inherently improve levels of driver stress through providing safer over-taking opportunities and accesses/egresses from the road.
11.6 Mitigation and Monitoring
11.6.1 The assessment has concluded there would be no requirement for mitigation relating to driver stress of view from the road.
11.7 Residual Effects
11.7.1 The impact assessment has determined that without requirement for mitigation specific to vehicle-travellers the associated impacts on driver-views and driver-stress will be ‘slight’ and ‘moderate’ respectively; noting the limitations to the assessment method in relation to the scheme proposals. As such, it is determined that there will be no significant residual effects.