16 Vehicle Travellers 16.1 Introduction 16.2 Approach and Methods 16.3 Baseline Conditions 16.4 Potential Impacts 16.5 Potential Mitigation 16.6 Summary of Route Corridor Options Assessment 16.7 Scope of Stage 3 Assessment 16.8 References
16 Vehicle Travellers
16.1 Introduction
16.1.1 This chapter presents the assessment of the Stage 2 route corridor options for the Forth Replacement Crossing on vehicle travellers in terms of view from the road and driver stress.
16.1.2 View from the road is defined as the extent to which vehicle travellers are exposed to different types of scenery through which the proposed scheme passes. The existence of a new road provides the opportunity for more people to view the landscape and appreciate their location in relation to distinctive landscape features. Views from a new road, or section of a road, may also help to alleviate driver stress. Conversely, where views from a road are restricted by the topography of a new construction, this may cause frustration or contribute to driver boredom.
16.1.3 Driver stress is defined as the mental and physiological effects experienced by a driver using a road network. The three main components of driver stress are frustration, fear of a potential accident, and uncertainty of the route which is being followed.
16.1.4 Impacts during construction are considered in Chapter 17 (Disruption Due to Construction).
16.2 Approach and Methods
16.2.1 The assessment of impacts on Vehicle Travellers has been undertaken following guidance provided in DMRB Volume 11, Section 3, Part 9 (The Highways Agency et al., 1993).
View from the Road
16.2.2 The assessment takes into account the types of scenery or landscape character, the extent to which travellers would be able to view the scene, the quality of the landscape and features of particular interest or the prominence of the view.
16.2.3 The extent to which travellers will be able to perceive the landscape through which they are passing will vary with the relative level of the road and its surrounding topography and vegetation. The categories used to assess this are:
- no view — road in very deep cutting or contained by earth bunds, environmental barriers or adjacent structures;
- restricted view — road in frequent cuttings, or with deep cuttings across slopes, with frequent environmental barriers or adjacent structures blocking the view;
- intermittent view — road generally at grade but with shallow cuttings, environmental barriers or structures at intervals; and
- open view — road generally at grade or on embankment with views extending over the wider landscape or only restricted by existing landscape features.
Driver Stress
16.2.4 Driver stress has been assessed using the following three point scale as recommended in DMRB:
- high;
- moderate; and
- low.
16.2.5 Driver stress levels are predicted by forecasting the average peak (peak is taken as 08h00-09h00 and 17h00-18h00) hourly flow per lane for each section of the route and the average journey speed on that section. The baseline (existing) traffic conditions have been calculated using 2005 traffic flows. In accordance with the guidance in DMRB, the assessment of Driver Stress for the Forth Replacement Crossing is based on the highest traffic flow in the first 15 years after opening, which has been taken to be 2032. The baseline / forecast traffic flows and predicted journeys speeds used for the assessment are provided in Appendix A16.1.
16.2.6 Tables 16.1 and 16.2 present the guidance on categorisation of driver stress provided by DMRB based on flow and speed for a motorway and dual carriageway respectively. The motorway categories apply to the sections of route where motorway regulations apply — namely north of Admiralty in the Northern study area and south of the A904 or Scotstoun Junction in the Southern study area. The dual carriageway category applies to the section of the A90 between Admiralty and Ferrytoll, the proposed replacement bridge and the A90 to the south of the Firth of Forth. The categories only apply to those sections of road where traffic flows and speeds are relatively constant over 1km or more of the route and are therefore only presented for the sections of the mainline between individual junctions.
Table 16.1 - Driver Stress Levels on Motorways
Average Peak Hourly Flow per Lane 1 |
Average Journey speed km/hr |
||
|---|---|---|---|
Under 75 |
75 - 95 |
Over 95 |
|
Under 1200 |
High |
Moderate |
Low |
1200 — 1600 |
High |
Moderate |
Moderate |
Over 1600 |
High |
High |
High |
Table 16.2 - Driver Stress Levels on Dual Carriageway Roads
Average Peak Hourly Flow per Lane 1 |
Average Journey speed km/hr |
||
|---|---|---|---|
Under 60 |
60 — 80 |
Over 80 |
|
Under 1200 |
High2 |
Moderate |
Low |
1200 — 1600 |
High |
Moderate |
Moderate |
Over 1600 |
High |
High |
High |
1 A car or light van equals one flow unit. A commercial vehicle over 1.5 tons unladen weight or a public service vehicle equals 3 flow units.
2 ‘Moderate’ in urban areas.
16.2.7 It should be noted that the levels of driver stress predicted are relative, i.e. driver stress would be significantly affected by nationally anticipated increases in traffic volumes (i.e. increased driver stress in the do-minimum scenario) and not specifically a consequence of the Forth Replacement Crossing project.
16.3 Baseline Conditions
View from the Road
16.3.1 The descriptions of views from the existing road network around the study area have been produced based upon desk based assessment and knowledge of the roads gained through field survey and informed by the visual assessment (Chapter 11: Visual).
Firth of Forth
16.3.2 Views from the Forth Road Bridge are partially obstructed by the surrounding structure and safety barriers on the bridge which allow intermittent views. In clear weather, views west along the estuary extend to Grangemouth and Kincardine. Views east are dominated by the Forth Rail Bridge, with limited views beyond North Queensferry to Dalgety Bay and the islands in the estuary. The towers and cables of the Forth Road Bridge filter the views directly north and south along the Forth Rail Bridge, allowing only glimpses of South Queensferry, Castlandhill and Ferry Hills.
Northern Study Area
16.3.3 The A90 crosses Fife, becoming the M90 at the southern edge of Rosyth. To the south of the settlement, the views to the eastern side of the road are constrained by the rock cuttings adjacent to the carriageway. These cuttings have weathered to achieve a naturalised appearance as features in the landscape, which mitigates the sense of enclosure. Intermittent views are available to the west across coastal grassland, punctuated by roadside planting and small rock cuttings at Ferry Toll roundabout. Southbound traffic has views along the carriageway towards the Firth of Forth, with views of the Forth Road Bridge framed by rock cuttings, creating an ‘approach’ experience. Open views beyond Rosyth are across settlement to the west and over farmland and an industrial estate to the east. The road returns to cutting and with restricted or no views as it continues north past Dunfermline, although roadside planting softens the resulting sense of enclosure.
16.3.4 North of Inverkeithing, the A921 and A985 provide the main east-west route, crossing the existing M90 at Junction 1A. Inverkeithing Industrial Estate, near the M90, degrades views north from the A921, but beyond Inverkeithing there are attractive open views across farmland which rises northwards to Fordell Estate. The rising landform south of the road restricts views towards the Firth of Forth. West of the M90, the A985 has no views within Rosyth and open rural views thereafter. Views from the A823(M) to Dunfermline, which runs west from Junction 2 of the M90, are restricted by landform, vegetation and within the town, settlement.
Southern Study Area
16.3.5 Beyond the confines of Edinburgh, views from the A90 are generally restricted between Cramond Bridge and South Queensferry by woodland, topography and occasional cuttings, with intermittent views to the west across the surrounding farmland. From Dalmeny, there are intermittent views south across adjacent farmland towards Kirkliston, partially screened by the M9 Spur. At Ferry Muir, restricted views towards the Forth Road Bridge are glimpsed for northbound traffic, before more open views across the Firth of Forth become available, enhanced by the recent removal of the toll barriers.
16.3.6 The M9 Spur was completed in 2007 to cater for the volume of traffic between the Forth Road Bridge and the M9. Between the M9 Junction 1A and the new overbridge across the A8000, open views are available across Kirkliston to the east of the road, with short-range views to the west contained by the topography and woodland of Dundas Estate and Humbie Farm. Beyond Dundas Estate, the elevation of the road allows glimpses of the Forth Road Bridge and Forth Rail Bridge across rolling farmland. Southbound traffic has open views across farmland towards Edinburgh Airport, with views restricted by deep cuttings, as the road passes Royal Elizabeth Yard industrial estate. At the merge with the A90, views north are limited by South Queensferry settlement.
16.3.7 The A904 follows a sinuous route west from Ferry Muir roundabout, at the southern edge of South Queensferry, towards Linlithgow, with generally open views across the surrounding farmland. Between Newton and South Queensferry, eastbound traffic has open, scenic views across the Firth of Forth towards the Forth Road Bridge and Forth Rail Bridge, partially screened by Headrig Hill. From the A8000 from Kirkliston to South Queensferry, which until recently provided a major link to the Forth Road Bridge, travellers have intermittent rural views to the east of the road and limited views to the west into Dundas Estate, with glimpses north to the towers of the Forth Road Bridge.
Driver Stress
16.3.8 The level of driver stress on the A90 and M90 during the peak periods in 2005 was generally moderate to high. In the inter-peak period, driver stress was generally low, except for the Forth Road Bridge and A90 to the south of the Firth of Forth, where driver stress was moderate.
Limitations to Assessment
16.3.9 As part of the DMRB Stage 2 assessment, detailed mitigation proposals will not be developed. Mitigation earthworks, landscape and ecological planting, walls, fences and noise barriers would potentially affect views from the road. At this stage the residual impacts of the change to views cannot therefore be confirmed.
16.4 Potential Impacts
16.4.1 This assessment is based on potential impacts (i.e. without mitigation). As noted in paragraph 6.2.7, potential impacts in terms of driver stress are significantly affected by nationally anticipated increases in traffic volumes with or without the Forth Replacement Crossing.
Forth Replacement Bridge
View from the Road
16.4.2 Views from the proposed replacement bridge would be very similar to those from the Forth Road Bridge. As with the Forth Road Bridge, the bridge structure itself would permit only intermittent views. The alignment of the crossing would increase views of the industry in Rosyth Europarc, but travellers would still have attractive views west along the Firth of Forth, with the Forth Road Bridge and Forth Rail Bridge dominating and screening views to the east. Substantial wind deflection structures, to reduce the effects of high winds and frequency of bridge closures, would potentially interrupt views depending on the design/form used. Views along the carriageway would be limited by the towers of the proposed replacement bridge, with intermittent views north to Castlandhill and the Ferry Hills, and south to the wooded hill of Dundas Estate and surrounding farmland.
Driver Stress
16.4.3 By 2032, driver stress on the proposed replacement bridge is likely to be high during peak periods and moderate at times of lower travel demand, due to a combination of high flows and low forecast speeds.
Northern Route Corridor Options
North Corridor Option 1
View from the Road
16.4.4 This route corridor would join the existing A90 immediately north of the proposed replacement bridge. Between St Margaret’s Hope hill and the route tie-in, the road would have open views west towards the Firth of Forth. To the east, intermittent short-range views would be contained by the rock cutting through Ferry Hills and roadside planting north of The Queensferry Hotel.
16.4.5 Beyond the tie-in, views for travellers would be very similar to those from the existing A90. Between Castlandhill and Muckle Hill/Fairy Kirk hill, views would be restricted by rock cuttings, the original sections of which are weathered and would frame views of the new bridge for southbound travellers.
16.4.6 North of the cuttings, open views across Rosyth and farmland to the east would remain unchanged, although views would be partially disrupted by the structure and embankments of the revised Masterton Junction. The upgraded junction would require removal of existing trees to accommodate a more elevated carriageway, creating intermittent views to the east across the adjacent farmland. East of Duloch Home Farm there would be no views where the road enters a cutting as it passes beneath the B916.
Driver Stress
16.4.7 Driver stress on the M90 and A90 is likely to be high at peak times under North Corridor Option 1 due to the relatively high flow per lane forecast in 2032. However, driver stress may be categorised as moderate at other times, particularly on the motorway section north of Masterton Interchange, which has been assessed as low or moderate during the inter-peak period.
North Corridor Option 2
View from the Road
16.4.8 This route corridor would be constructed offline before tying back into the existing M90 to the south of the B916. Beyond St Margaret’s Hope hill, the road would be elevated with open views west towards the Firth of Forth. Intermittent views to the east would overlook the B981 to North Queensferry and the existing A90 towards the rock cutting through Ferry Hills.
16.4.9 After Ferry Toll Junction, there would be no views from the road as it cuts through Whinny Hill, Castlandhill and Fairy Kirk hill. The alignment would limit the opportunity for an approach experience prior to reaching the proposed replacement bridge.
16.4.10 North of Fairy Kirk hill, the elevated road would enable open views west across Inverkeithing Industrial Estate to Dunfermline. More attractive open views to the east would be anticipated across the farmland valley between Fordell Estate to the north and Letham Hill to the south.
16.4.11 The approach to the final merge with the M90 would be in cutting, which would restrict the views available to the side of the road, while the rising landform would restrict views north. Southbound travellers would have views along the carriageway towards the Forth Rail Bridge.
Driver Stress
16.4.12 Driver stress is forecast to be high on the new offline section of dual two lane motorway and on the proposed replacement bridge. From the northern extent of the proposed scheme and the start of the offline section of new carriageway, driver stress is likely to be moderate to high during peak periods and moderate at other times. Drivers on the existing M90 / A90 carriageway connecting Masterton Interchange, Admiralty and Ferrytoll would be expected to experience low levels of driver stress due to the reduction in traffic on these sections of network as a consequence of constructing North Corridor Option 2.
Southern Route Corridor Options
South Corridor Option 1
View from the Road
16.4.13 The initial section of road to the south of the proposed replacement bridge would be situated on a small embankment as it diverges from the A90, with open views to either side and views north towards the Forth Road Bridge.
16.4.14 The road would be in cutting as it continues to the west towards the A904 and passes beneath the new junction with the A904, with no views available due to the surrounding landform. Southbound traffic would have intermittent views along the carriageway towards the southern edge of South Queensferry and the adjacent farmland, while views along the road for northbound travellers would be restricted by cuttings.
16.4.15 North of the A904, the road would move onto embankment, with open views west for northbound traffic across farmland towards Hopetoun Estate, and north across the Firth of Forth. From the southbound carriageway, intermittent views would be available towards South Queensferry and the woodland of Dundas Estate, interrupted by the A904 Junction overbridges.
16.4.16 The changes to the Echline / Scotstoun Junction would not represent a significant change to existing intermittent views, while the new M9 Junction 1A would require the majority of vegetation on the western side of the junction to be removed, enabling open views across farmland towards Dundas Estate, although the scenic quality of the views would be degraded by the bings near Niddry Mains.
Driver Stress
16.4.17 Driver stress on the section of dual carriageway between the proposed replacement bridge and the revised Echline / Scotstoun Junction is likely to be high during peak periods due to the combination of high flows and low speeds that are forecast in 2032. Driver stress will be moderate at times of lower travel demand. However, on the A90 to the west of Scotstoun, driver stress has been assessed as moderate at all times and on the M9 Spur to the south of Scotstoun, driver stress has been assessed as moderate at peak times and low in the inter-peak period.
South Corridor Option 2
View from the Road
16.4.18 The embankments for the new carriageway between the M9 and Humbie Reservoir would provide travellers with open views east across farmland and west towards the large bing near Niddry Mains. Beside the reservoir, views would be restricted by the structures and embankments of the new slip roads. Open views would be available from the elevated slip roads across the reservoir and adjacent woodland areas. Northbound views along the carriageway would be restricted by local topography and overbridges, while southbound travellers would have attractive open views across farmland.
16.4.19 Beyond Swineburn, the road would be briefly at grade, with open views to both sides of the road across farmland. The road would then move into deep cutting, which would restrict views for travellers, with occasional glimpses of isolated woodland to the west and Dundas Estate to the east. The route corridor would remain in cutting until it had passed the proposed junction with the A904.
16.4.20 In the vicinity of Westfield Farm, intermittent views north along the carriageway to the towers of the new bridge would be anticipated, with localised screening by landform and the overbridges for the local road and the A904 Junction. Southbound views directly ahead would be to Swineburn Wood and the bings near Niddry Mains.
16.4.21 Views from the final stretch road to the south of the proposed replacement bridge would be the same as for South Corridor Option 1.
16.4.22 The extended straight alignment south of the proposed replacement bridge would potentially provide travellers with a longer approach experience than South Corridor Option 1, dependent on topography and overbridges.
16.4.23 This option would include a revised layout for the Scotstoun Junction, where the M9 Spur merges with the A90. However, this change would be unlikely to cause a discernible change to the existing views for travellers.
Driver Stress
16.4.24 By 2032, driver stress between the proposed replacement bridge and the M9 to the north of M9 Junction 1A has been assessed as high at peak periods and moderate at other times. The rerouting of traffic from the M9 Spur to the new motorway link would result in driver stress on the M9 Spur being low at all times. Driver stress on the A90 to the east of Scotstoun would remain moderate.
16.5 Potential Mitigation
View from the Road
16.5.1 At this stage of the assessment, detailed mitigation measures have not been developed, so it is not possible to assess to what extent views would be altered by mitigation earthworks, landscape and ecological planting, walls, fences and noise barriers. However, for each route corridor option, areas where potential mitigation could be introduced to enhance the journey experience for drivers have been identified.
16.5.2 Without appropriate mitigation, the source of adverse impacts for travellers are likely to include the following:
- journeys through deep cuttings causing a distressing sense of enclosure for drivers;
- lack of distant views ahead along the carriageway causing lack of certainty about the route; and
- change to existing route to reveal or increase views of unattractive features.
16.5.3 Mitigation measures include the prevention of impacts through the selection of a route corridor option that provides the most varied journey experience, maximising opportunities to appreciate scenic and valued views and providing adequate stretches of long-distance views ahead along the carriageway. The best fit within the landscape and the reduction / offsetting of impacts is also sought through the use of:
- elevation - construct the road at grade where possible;
- earthworks - tie in cuttings and embankments with the natural landform;
- rock cuttings - create naturalistic looking rock faces; and
- planting and seeding - integrate with surrounding ground cover, scrub or woodland, replace lost vegetation, provide screening and soften/vary the sense of enclosure.
16.5.4 Potential mitigation measures for each option are outlined below.
North Corridor Option 1
- minimise the extent of new rock cutting through Castlandhill / Muckle Hill section and retain the weathered existing rock cuts to reduce the sense of enclosure; and
- retain the existing vegetation beside the road to the north of the Masterton Junction where possible to soften the sense of enclosure.
North Corridor Option 2
- grade out the cutting slopes through Castlandhill and Fairy Kirk hill to enhance the fit with the landscape and ensure the rock cutting method achieves a naturalistic appearance;
- replace planting around the cutting through Fairy Kirk hill to soften the appearance and offset the loss of existing vegetation; and
- replace planting at the M90 split where possible, to soften the appearance of the cutting.
South Corridor Option 1
- grade out the cutting slopes to improve the landscape fit and reduce the sense of enclosure at the A904 junction;
- replace woodland lost at the edge of Dundas Estate to improve the appearance of the severed woodland edge; and
- introduce roadside planting where appropriate, such as adjacent to Dundas Estate, to vary and soften the sense of enclosure.
South Corridor Option 2
- replace woodland lost at the edge of Swineburn Wood to improve the appearance of the severed woodland edge and improve the fit of embankments within the landscape;
- grade out the cutting slopes to improve the landscape fit and reduce the sense of enclosure at the A904 junction;
- introduce roadside planting, where appropriate, to vary and soften the sense of enclosure; and
- promote views towards the proposed replacement bridge to enhance the approach experience.
Driver Stress
16.5.5 The Forth Replacement Crossing will be designed to appropriate road design standards in accordance with DMRB. The objective is to ensure that the design (including aspects such as gradients, junctions, lane change requirements) enables traffic to flow freely and are able to manoeuvre within the traffic stream with relative ease. Driver stress will be highest where a driver’s ability to manoeuvre is constrained by a combination of high traffic flows or a high proportion of large vehicles and constrained road capacity.
16.5.6 Fear can be reduced by ensuring that sight distances generally comply with the current standards, giving a clear view of the carriageway ahead. The provision of adequate lighting at junctions may also help to reduce fear in vehicle travellers undertaking their journey at night. Current design standards do not require road lighting for the full length of the Forth Replacement Crossing.
16.5.7 Driver stress in terms of route uncertainty can be minimised by the provision of signs designed and sited in accordance with the appropriate standards.
16.6 Summary of Route Corridor Options Assessment
Northern Route Corridor Options
16.6.1 Overall, North Corridor Option 1 would offer the most benefits in terms of views for travellers and woukld be likely to result in comparatively less driver stress.
North Corridor Option 1
View from the Road
16.6.2 North Corridor Option 1 would offer the most open and varied views for travellers, with views across farmland to the north of Inverkeithing and a view, framed by weathered rock cuttings, of the approach to the new bridge.
Driver Stress
16.6.3 Driver stress has been assessed as high during peak times and moderate at other times for North Corridor Option 1.
North Corridor Option 2
View from the Road
16.6.4 The route corridor for North Corridor Option 2 would be likely to require substantial new rock cuttings, which could appear conspicuous and unweathered for several years.
16.6.5 North of Fairy Kirk hill, North Corridor Option 2 would provide travellers with attractive open views across the rolling farmland to the east and views southwards from the higher ground towards the Forth. However, the cuttings through Whinny Hill, Castlandhill and Fairy Kirk hill and the sinuous alignment would severely restrict the views and minimise opportunities for drivers to gain an approach experience to the new bridge.
16.6.6 Overall North Corridor Option 2 would provide the most enclosure and least variety in views for travellers.
Driver Stress
16.6.7 North Corridor Option 2 is likely to result in high levels of driver stress during most periods as a result of the lesser carriageway provision on the offline section compared to North Corridor Option 1. However, drivers using the existing section of M90 / A90 that is bypassed by the offline section are likely to experience low levels of driver stress.
Southern Route Corridor Options
16.6.8 Overall, it is considered that impacts on vehicle travellers would be of similar significance for either of the southern route corridor options.
South Corridor Option 1
View from the Road
16.6.9 Views from South Corridor Option 1 would be generally intermittent since the majority of the route corridor would be in cutting. This short route would provide a very brief approach experience in terms of view of the new bridge, although the short distance that would need to be travelled would reduce the amount of time that travellers would be enclosed.
Driver Stress
16.6.10 Levels of driver stress are likely to be high at peak times and moderate during the inter-peak period for South Corridor Option 1 on the proposed replacement crossing, similar to those anticipated for South Corridor Option 2. Under South Corridor Option 1, drivers are likely to experience moderate driver stress for the remainder of their journeys on the A90 or M9 Spur east or south of the reconfigured Echline / Scotstoun Interchange.
South Corridor Option 2
View from the Road
16.6.11 South Corridor Option 2 would provide a long approach to the crossing, maximising the opportunity to appreciate a view of the Forth Road Bridge, the Forth Rail Bridge as well as the proposed replacement bridge. However, the majority of this route corridor would be in cutting, with restricted rural views to either side of the road. Although the elevated approach to M9 Junction 1A would provide drivers with an open view to the south, it would be dominated by the large bing near Niddry Mains, which would have an adverse impact on the scenic quality of the view.
Driver Stress
16.6.12 As with South Corridor Option 1, driver stress is likely to be high at peak times and moderate during the inter-peak period. However, with South Corridor Option 2, a greater proportion of bridge traffic would remain on the proposed motorway link between the A904 and M9, resulting in high driver stress on this section at peak times. However, driver stress would be low on the M9 Spur throughout the day.
16.7 Scope of Stage 3 Assessment
16.7.1 The Stage 3 assessment for Vehicle Travellers will be undertaken in accordance with the DMRB Volume 11, Section 9 and will include the following:
- assessment of impacts on driver stress, using updated traffic data based on the proposed scheme;
- review of the Stage 3 visual assessment to inform the view from the road, taking account of landscape and visual mitigation during winter year of opening and summer 15 years after opening; and
- identification of any further mitigation, including input where appropriate into aspects such as signage and lighting.
16.8 References
The Highways Agency et al. (1993).DMRB, Volume 11, Vehicle Travellers, Section 3, Part 9, June 1993. The Highways Agency, Scottish Executive Development Department, The National Assembly for Wales and The Department of Regional Development Northern Ireland.