in respect of scheme design and engineering · 02/06/2014 · appendix 22 bridge over malago...

NSC/2/1

THE NORTH SOMERSET COUNCIL (SOUTH BRISTOL LINK CLASSIFIED ROAD)

SIDE ROADS ORDER 2013

THE NORTH SOMERSET COUNCIL (SOUTH BRISTOL LINK)

COMPULSORY PURCHASE ORDER 2013

THE NORTH SOMERSET COUNCIL (SOUTH BRISTOL LINK)

COMPULSORY PURCHASE ORDER (No 2) 2014

EXCHANGE LAND CERTIFICATES IN RESPECT OF SPECIAL CATEGORY LAND

PROOF OF EVIDENCE OF

PHILIP PATERSON BSc, CEng, MICE, MCIHT

ON BEHALF OF

NORTH SOMERSET COUNCIL

IN RESPECT OF

SCHEME DESIGN AND ENGINEERING

SCHEME DESIGN AND ENGINEERING NSC/2/1

Contents

1 . Personal Details

2. Scope of Evidence

3. Design Standards

4. The Alignment

5. Alignment Options Considered

6. The Major Junctions

7. Minor Junctions and Accesses

8. Provision for Pedestrians and Cyclists

9. Scheme Engineering

10. Departures from Standards

11. Consideration of Objections

12. Conclusions

Appendices (contained in NSC/2/2)

Appendix 1 Design Standards

Appendix 2 Scheme Cross-sections

Appendix 3 Scheme Layout Drawings

Appendix 4 Alignment Options Considered - A370 to A38

Appendix 5 Options Considered for Location of Railway Crossing

Appendix 6 Options Considered from A38 to Highridge Road

Appendix 7 Junction Options Considered at Brookgate

Appendix 8 Junction Options Considered at the A38

Appendix 9 Junction Options Considered at Highridge Road

Appendix 10 Junction Options Considered at Queens Road

Appendix 11 Junction Options Considered at Hareclive Road

Appendix 12 Network Rail Maintenance Access at Underbridge

Appendix 13 Amended Access at Chainage 2195

Appendix 14 Access to Residential Premises off Highridge Green

Appendix 15 Affected Watercourses


Appendix 16 Environment Agency Flood Zones

Appendix 17 Drainage Catchment Areas and Attenuation

Appendix 18 Longmoor Brook Underbridge - General Arrangement

Appendix 19 Col/iter's Brook Culvert - General Arrangement

Appendix 20 Col/iter's Brook Underbridge - General Arrangement

Appendix 21 Colliter's Brook Retaining Wal/s - General Arrangement

Appendix 22 Bridge over Malago Culvert - General Arrangement

Appendix 23 Departures from Standards

ii


Glossary

AOD Above Ordnance Datum (height relative to the average sea level

at Newlyn, Cornwal/ UK)

AVTM Ashton Vale to Temple Meads

BCC Bristol City Council

BS5489 Code of practice for the design of road lighting. Lighting of roads

and public amenity areas.

CAFRA Central Area Flood Risk Assessment prepared by Bristol City

Council and the Environment Agency in 2013

DEFRA Department for Environment, Food and Rural Affairs

DMRB Design Manual for Roads and Bridges published by the Highways

Agency

DMSSD Desirable Minimum Stopping Sight Distance

EA Environment Agency

km kilometres

LED Light Emitting Diode

lIs litres per second

m metres

NPPF National Planning Policy Framework

NSC North Somerset Council

SATURN Simulation and Assignment of Traffic to Urban Road Network

Selective Vehicle Selective vehicle detection is a bus priority system to al/ow traffic

Detection signals to selectively favour buses' movement through junctions

by changing traffic light sequences and timings as buses

approach.

Toucan A toucan crossing is a type of pedestrian crossing that also al/ows

bicycles to be ridden across.

iii


1. Personal Details

1.1. My name is Philip Paterson. I have been employed by CH2M Hil/ (formerly

Halcrow Group Ltd) since 1983 and I am an Associate Director. My responsibility

is to lead the design of highway projects.

1.2. I hold a BSc Honours degree in Civil Engineering. I am a Chartered Engineer and

a Member of the Institution of Civil Engineers and the Chartered Institution of

Highways and Transportation.

1.3. I have in excess of 30 years experience in civil engineering, primarily in the field

of highway engineering. This has included working on a wide variety of projects

and has included working on projects across the ful/ range of stages, from

inception through to construction. Concurrent with working as Design Manager

for the Scheme, I have been Project Manager for the design of a major highway

junction improvement for Swindon Borough Council, under CH2M Hii/'s

framework contract with the Council, and prior to that Halcrow's Project Manager

for the design of the Barnstaple Western Bypass for Devon County Council,

opened in 2007. I have also led design teams on a number of major highway

schemes, including 40km of highway for the new Chek Lap Kok Airport in Hong

Kong, the dual/ing of 10km of Castle Peak Road in Hong Kong and the design of

around 40km of new and improved highway on New Providence Island in the

Bahamas.

1.4. My proof of evidence sets out the rationale behind the route of the South Bristol

Link (the Scheme) from a highway alignment perspective and set outs the

reasoning behind the choice of junctions along the route. My proof of evidence

also summarizes the engineering that supports the scheme layout.

1 .5. i hereby declare that insofar as the contents of this proof of evidence are matters

within my knowledge they are true. Insofar as they are not within my direct

knowledge, they are true to the best of my knowledge and belief and are drawn

from documentation and information to which I have had access.


2. Scope of Evidence

2.1 . I start my evidence with a description of the standards to which the Scheme has

been developed.

2.2. I then set out the rationale for the alignment of the Scheme, starting from its

junction with the A370 to the north and moving southwards and then eastwards

to its connection to the existing Cater Road roundabout. I then describe the

options considered in arriving at the preferred alignment.

2.3. i then set out the reasoning behind the junction types along the alignment,

starting with the junction with the existing A370 to the north, then the junction at

Brookgate, and subsequently the junctions with the existing A38, Highridge

Road, Queens Road, Hareclive Road and final/y the connection to the existing

road network at Cater Road roundabout. This is fol/owed by a discussion of

junction options considered.

2.4. Fol/owing on from my evidence on the major junctions, i describe the minor

junctions and accesses to be provided to discrete parcels of land along the

Scheme.

2.5. After consideration of the junctions i present the provision for pedestrians and

cyclists.

2.6. My evidence on the Scheme layout is then fol/owed by a summary of the scheme

engineering, broken down into sub-sections on geotechnics, drainage, structures

and street lighting.

2.7. After the presentation of the Scheme engineering, there is a section on

Departures from Standards.

2


2.8. This is fol/owed by a response to objections received that relate to the Scheme

design and engineering.

2.9. My proof of evidence is then completed with conclusions.

3


3. Design Standards

3.1. The design objectives for the Scheme are:

i. To design a road and associated facilities that comply with current design

standards, resulting in a road that is accessible, effective and safe for aI/

users.

ii. To minimise the environmental impact of the Scheme whilst achieving the

overal/ objectives.

Hi. To design the facilities with due consideration to all user groups, including

those driving the route and those cycling or walking along or across the

route.

iv. To design the Scheme with due consideration to those adjacent to the route

and who will be impacted upon by the road and its associated facilities.

v. To design the route with due consideration to the views expressed by aI/

stakeholders, from statutory consultees to local residents and businesses.

3.2. The overarching design standards are those contained within the Design Manual

for Roads and Bridges published by the Highways Agency. For this project these

have been supplemented by project specific geometric design criteria.

3.3. The key standards from the Design Manual for Roads and Bridges used in the

development of the design to date are set out in Appendix 1 in NSC/2/2,

together with the project specific design criteria.

3.4. The typical cross-sectional widths to be applied to each section of the Scheme,

resulting from the consideration of the standards mentioned above, are il/ustrated

in Appendix 2 in NSC/2/2.

4

SCHEME DESIGN AND ENGINEERINGNSC/2/1

4. The Alignment

4.1. The alignment of the Scheme is described in the fol/owing paragraphs and is

il/ustrated on the drawings included within my Appendices 3A to 3E, contained

in NSC/2/2. These drawings are those for which Planning consent has been

granted (CD2/19 to CD2I23), annotated where appropriate for clarity to include

locations/places that are referred to within the text below.

A370 to Network Rail Underbridge (Appendix 3A and Appendix 3B in NSC/2/2)

4.2. The Scheme starts from a new junction with the existing A370 and heads in a

south easterly direction initial/y on a straight and then on a right hand bend of

radius 360 metres. The alignment then straightens at the junction with Brookgate

before continuing towards a crossing beneath the Network Rail Bristol to Taunton

railway line.

4.3. The road in this section reduces in height from the A370 (14 metres AOD) down

to the minimum elevation required to al/ow the inclusion of Longmoor Brook

Underbridge (9 metres AOD) before returning to an elevation of 14.5 metres AOD

to pass beneath the railway line.

4.4. In cross-section the road is general/y of a single carriageway, consisting of two

lanes of width 3.375m. Widening of the carriageway and the verges on the bend

has been provided in accordance with the design standards on the grounds of

safety. South of the Brookgate junction the cross-section includes a nearside bus

lane of width 3.0 metres in each direction, providing continuity of provision for

buses to the dedicated bus link described below.

4.5. A shared use walking and cycling facility of width 3 metres has been provided to

the east of the road, connecting to the existing bridge over the A370 and

general/y running adjacent to the road.

5


Bus Link (Appendix 3A and Appendix 3B in NSC/2/2)

4.6. From the junction at Brookgate a dedicated bus link heads in a northerly direction

to connect to the Ashton Vale to Temple Meads scheme (AVTM) and from there

to the Park and Ride site. The link is located adjacent to Colliter's Brook, at a

distance to provide adequate maintenance access width for the Environment

Agency.

4.7. The link is a single carriageway of width 6 metres and the vertical alignment is

general/y flat, with minimum gradients to facilitate drainage. The elevation rises

on the approach to the Brookgate junction to tie in to the Scheme. The elevation

of the road has been set making al/owance for drainage of the adjacent land.

4.8. A shared use walking and cycling facility of width 3 metres is provided to the east

of the link, adjacent to the road.

Network Rail Underbridge to A38 (Appendix 3B and Appendix 3C in NSC/212)

4.9. The location of the railway crossing was fixed taking into account the relative

levels of the railway and the existing ground, the location of the existing

underpass beneath the railway, the location of strategic water mains, the existing

structure carrying Col/iter's Brook beneath the railway and the lagoons within the

landfil/ site.

4.10. The alignment south of the existing railway crossing consists of a series of

flowing curves of radii 360 metres, 510 metres and 360 metres to mitigate

impacts on the adjacent Col/iter's Brook, Hanging Hill Wood and the landfil/ site.

4.11. The road in this section is general/y flat between the railway and Hanging Hil/

Wood, with minimal fal/s to facilitate drainage, but from the crossing of Colliter's

Brook climbs at a gradient of 7.9% to the junction with the A38. This profile

remains as close as possible to the existing ground level, minimising the footprint

of the Scheme and hence the environmental impact. While the gradient in this

section exceeds the defined project specific criteria, it fal/s within the standards

set out in the DMRB, and was agreed with the Highway Authority.6


4.12. The cross-section of the road consists of a single lane in each direction with

nearside bus lanes in each direction. Widening of the carriageway and the

verges through the curves has been provided in accordance with the design

standards on the grounds of safety.

4.13. A shared use walking and cycling facility of width 3 metres is provided to the east

of the road, adjacent to the carriageway.

A38 to Highridge Common (Appendix 3C and Appendix 3D in NSC/2/2)

4.14. The location of the roundabout junction with the existing A38 was fixed from

consideration of the impact on Castle Farm and the need to retain the existing

triple-conjoined lime kilns.

4.15. The alignment then moves in an easterly direction in a series of flowing curves of

radii 510 metres, 180 metres and 180 metres to where the Scheme meets with

the existing Highridge Green, from which point the alignment follows the line of

the existing road to its junction with Highridge Road. The curved alignment was

selected to address comments arising through the consultation process, to

reduce vehicle speeds, to avoid significant trees and provide adequate continuity

of width between the common and the exchange land.

4.16. The profile of the road is such that it fol/ows the existing ground profile, with

minimal earthworks.

4.17. The cross-section consists of a single carriageway with one lane in each direction

of width 3.375 metres. Widening of the carriageway and the verges through the

curves has been provided in accordance with the design standards on the

grounds of safety.

4.18. It is proposed that the speed limit for the Scheme changes on the approach to

the common, from 40mph in the more rural section to the north to 30mph in the

residential area.

7


4.19. A shared use walking and cycling facility of width 3 metres is provided to the

north of the road, adjacent to the carriageway.

Highridge Road to Queens Road - King Georges Road (Appendix 3D in

NSC/2/2)

4.20. The alignment in this section fol/ows the line of the existing King Georges Road,

both in plan and elevation.

4.21. The cross-section consists of a single lane in each direction of width 3.05 metres

with a flush median strip provided to facilitate crossing of the road and right

turning of vehicles into premises. A number of kerbed islands wil/ be included

within this central strip to facilitate safe crossing of the road by pedestrians. This

cross-section results in a widening of the existing road by 3.7 metres on average.

4.22. A shared use walking and cycling facility of width 3 metres is provided adjacent to

the residential properties on the northern side and a footway is provided similarly

on the southern side. Consideration was given to locating these facilities

immediately adjacent to the road but, given the locations of existing utilities, this

would have reduced the opportunities for landscaping.

Queens Road to Hareclive Road - The Reserved Corridor (Appendix 3D and

Appendix 3E in NSC/2/2)

4.23. The alignment in this section is again a series of flowing curves of radii 255

metres, employed to reduce vehicle speeds and emphasise the urban

characteristics of the road.

4.24. The profile of the road has been fixed to follow existing ground levels wherever

possible, in accordance with highway design standards.

4.25. The road in cross-section consists of a single carriageway with one lane in each

direction of width 3.65 metres. This incorporates appropriate widening on bends

as part of the consideration of safety. Within the main residential area, a 4 metre

wide central median has been included to reduce the impact of the carriageway8


and facilitate crossing of the road. Existing crossing points within the reserved

corridor have been established and these have been reflected in the scheme

layout, with one signalised crossing point and three non-signalised crossings

points.


north, adjacent to the carriageway.

Hareclive Road to Cater Road Roundabout (Appendix 3E in NSC/2/2)

4.27. The last section of the alignment connects Hareclive Road to the existing Cater

Road roundabout by way of a short section of existing new road and a section on

the line of the existing Whitchurch Lane.

4.28. The profile of the road has been fixed to fol/ow existing ground levels wherever

possible, in accordance with highway design standards.

4.29. The cross-section of the road is a single carriageway with one lane in each

direction of width 3.65 metres, incorporating appropriate bend widening. Along

the section on the existing line of Whitchurch Lane there is a flush central median

of width 3 metres to facilitate turning of vehicles.


north of the road, adjacent to the carriageway.

5. Alignment Options Considered

5.1. Although no objections have been received that relate to the overal/ alignment of

the Scheme, I provide below a brief summary of the options considered for a

number of sections. The consideration of these options resulted from extensive

engagement with the various Scheme stakeholders.

5.2. The sections are as fol/ows:

i. A370 to A38

ii. Railway crossing

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iii. A38 to Highridge Road junction

iv. King Georges Road

v. Reserved Corridor

vi. Hareclive Road junction to Cater Road roundabout

5.3. My involvement in the Scheme commenced in the summer of 2012 when CH2M

Hil/ (Halcrow) was commissioned by North Somerset Council to take forward

work undertaken to that time by Mott MacDonald. The alignment as developed by

Mott MacDonald is referred to below as the pre-consultation layout.

5.4. A370 to A38

5.4.1. Arising from comments received during the stakeholder engagement exercise,

the opportunity was taken to reconsider the alignment in this section, particularly

south of the railway in the vicinity of Yew Tree farm. This review was focussed on

mitigating the impact on the farm and the environmental impact of the Scheme

within this section.

5.4.2. Having regard to the design criteria discussed in paragraph 3 above, 6 route

options were examined in addition to the pre-consultation layout. The options are

listed below:

i. Option 1

ii. Option 2

ii i. Option 3

iv. Option 4

v. Option 5A

vi. Option 5B

Alignment east of Colliter's Brook

Alignment through Ashton Vale trading estate

Alignment west of Hanging Hil/ Wood

Alignment west of Colliter's Brook

Alignment west of pre-consultation route north of railway tying

into Option 3

Alignment west of pre-consultation route north of railway tying

into Option 4

These options are illustrated in Appendix 4 in NSC/2/2 and are discussed below,

together with their advantages and disadvantages relative to the pre-consultation

route.

10


Except for Option 2 aI/ other routes considered are variations to the west of the

pre-consultation route and only Option 5 differs in its alignment north of the

railway line.

Pre-consultation layout

5.4.3. The pre-consultation route sets the base line for the options considered in this

section. The alignment is shown in Appendix 4 in NSC/2/2 and runs from a

junction on the A370 some 300m west of the Long Ashton Park & Ride to a

junction with the A38 which is just to the east of Castle Farm. The route runs

south easterly through open fields from the A370 and crosses under the railway

line close to Colliter's Brook. The route crosses the brook and runs on the east

side of the Col/iter's Brook val/ey then southwards east of Castle Farm where it

joins the A38.

Option 1 - alignment east of Col/iter's Brook

5.4.4. The main difference between this route and the pre-consultation route is that the

section south of the railway line through the Colliter's Brook val/ey is moved up to

30m west and runs closer to the brook in an attempt to reduce severance of farm

land and avoid landfill sites to reduce stabilisation requirements.

5.4.5. This option has a lower visual impact and less impact on the existing landfil/s.

Option 2 - alignment through Ashton Vale trading estate

5.4.6. This option was put forward to utilise existing roads and make use of an existing

crossing point of the railway. The route bisects Ashton Vale Trading Estate and

the alignment design did not enable the use of the existing railway crossing

without demolition of existing properties. This option was discounted and not

considered further due to the impact on the trading estate and the potential

demolition of properties when other viable options were available.

11


Option 3 - alignment west of Hanging Hil/ Wood

5.4.7. This route is the most westerly option considered and was introduced to movethe alignment away from Hanging Hill Wood. The route differs from the pre-

consultation route south of the railway. The route heads south west from the

railway, avoiding crossing Col/iter's Brook and heading sidelong up the val/ey

slope, and passes over the Viridor landfill site with a change in level of 60m. The

route passes Hanging Hil/ Wood at the top of the val/ey then continues south to

join the A38 west of Castle Farm. AI/ other options join the A38 east of the farm.

5.4.8. The advantages of this option are a lower impact on Col/iter's Brook and Yew

Tree Farm and a more sinuous route that would reduce vehicle speeds. There

would be, however, a higher visual impact and a higher impact on the existing

landfill sites.

Option 4 - alignment west of Colliter's Brook

5.4.9. This route differs from the pre-consultation route south of the railway. The route

keeps to the west of Colliter's Brook and takes advantage of the existing track

that accesses the Viridor landfil/ site. The route runs alongside Hanging Hil/

Wood and then crosses Colliter's Brook as it continues south to join the A38 east

of Castle Farm.

5.4.10. The advantages of this option are a lower impact on the existing landfil/s, lower

impact on Yew Tree Farm and reduced visual impact. The option would,

however, be closer to Hanging Hill Wood.

Options 5A and 5B - alignments west of pre-consultation route north of railway

tying into Option 3 or Option 4

5.4.11. These options cross over the railway 200m west of the pre-consultation route

where the railway embankment height is lower. The route runs from the same

point on the A370 but heads further west before going over the railway. The route

then crosses the Viridor land fill site to join either Option 3 or 4 as Options 5A and

12


5B respectively. Option 5A stays towards the top of the Col/iter's Brook val/ey

running to the west of Hanging Hill Wood to join Option 3. Option 5B heads to the

east of Hanging Hil/ Wood to join Option 4.

5.4.12. These options have the corresponding advantages and disadvantages to Options

3 and 4 south of the railway but have a higher visual impact by passing over the

railway and require additional lengths of road to provide similar connectivity to the

existing road network.

Comparison of options

5.4.13. The initial assessment concluded that Options 1 and 4 had fewer disadvantages

whilst the consultation route and Options 5A and 5B had the most. Further

topographical surveying was undertaken to al/ow a better understanding of the

impacts of both Options 1 and 4 in the vicinity of Colliter's Brook. There is an

existing access track that runs to the west of the brook to serve the landfill site

immediately south of the railway and the focus of the assessment was to

determine whether the line of this track could be utilised while minimising the

impact on Hanging Hil/ Wood. This proved to be the case and hence Option 4

was favoured over Option 1, the latter having a more significant environmental

impact.

5.4.14. From the point where Option 4 crosses Colliter's Brook at Hanging Hill Wood the

route climbs up to the A38. A number of options for the vertical alignment were

considered in this area with a view to:

i. facilitating the crossing of the Scheme by pedestrians,

ii. minimising the impact on the adjacent environment of Hanging Hill Wood and

Colliter's Brook, and

iii. minimising the impact on the existing landfil/s.

5.4.15. The proposed Scheme achieves these objectives by keeping the alignment close

to existing ground level, aI/owing passage of pedestrians beneath the Scheme at

Colliter's Brook and minimising the footprint of the Scheme and hence the

environmental impact on Colliter's Brook.

13

SCHEME DESIGN AND ENGINEERING

5.5. Railway crossing

NSC/2/1

5.5.1. This section of my evidence discusses the reasons why the crossing of the

Bristol to Taunton railway has moved west of its original location in the pre-

consultation design.

5.5.2. The need to consider options arose from the potential impact of the Scheme on

the pipelines operated by Bristol Water and Wessex Water. Four options were

proposed for discussion, Options A to D, with a view to reducing the costs to

divert the utilities. These options are summarised below and are il/ustrated in

Appendix 5 in NSC/2/2.

Option A - This was based on the bridge not moving

5.5.3. The cost to divert the water mains equipment would be in the region of £2.5m

which was deemed as significant and this option was discounted due to the

additional cost.

Option B - Move the bridge to the east by narrowing the structure and reducing

carriageway width

5.5.4. Although potential/y the bridge could be moved to the east to avoid the diversion

of the water mains equipment this option was discounted due to the potential

impact on the Brookgate industrial units.

Option C - Move the bridge to the west and onto Viridor land

5.5.5. This option requires the relocation of a pond and encroaches further on to Viridor

land. AI/owing for a 3m clearance from the western water main and adjustments

to connect into Brookgate this is aviable option with minimal impact on the water

mains equipment. This also allows for the retention of the existing arch structure

to provide a footwaylcycleway route.

14


Option D - Relocate bridge to a new position (further west)

5.5.6. This was discounted following comments from English Heritage on the visual

impact from Ashton Court and the cost of constructing the road on the landfil/.

Comparison of Options

5.5.7. It was clear that Option C advantages far outweigh the advantages of the other

options. There are also fewer disadvantages and hence Option C was the

favoured location to take forward.

5.6. A38 to Highridge Road junction

5.6.1. The pre-consultation and proposed routes are shown in Appendix 6 in NSC/212.

5.6.2. The first 750m runs through farm fields whilst the last 350m runs through and

alongside Highridge Common. The final 250m is along the alignment of the

existing Highridge Green road.

5.6.3. The first 450m approximately follows the line of the pre-consultation route,

although the junction with the A38 is slightly further east to accommodate the

lime kilns. The central 400m has been realigned by introducing back to back

curves to accommodate comments made by landowners and residents in the

consultation process to reduce the impact on property and the common. The

more sinuous alignment also has the effect of reducing speed as a road user

enters the common. The last section has been moved from the pre-consultation

alignment, which was further into the common, to fol/ow the line of the existing

Highridge Green road as much as possible, reducing the impact on the common.

5.6.4. Fol/owing confirmation of the proposed exchange land the distance between the

Scheme and Highridge Cottage was increased from approximately 10m to 20m,

by moving the alignment northwards. This has provided a greater width and

thereby has improved the connectivity between the existing common and the

exchange land.

15


5.7. King Georges Road

5.7.1. This section of the scheme is approximately 500m in length and runs along the

existing King Georges Road. There is very little scope to change the alignment

from that of the existing road due to the proximity of the residential properties and

the constraints imposed by the junctions with Highridge Road at the northern end

and Queens Road at the southern end.

5.7.2. However, arising from the stakeholder engagement exercise, the opportunity was

taken to consider a number of improvements, principal/y focussed on severance,

the potential loss of parking and the impact on the residential setting of the road.

5.7.3. A number of cross-sections were considered in order to achieve an optimal

scheme layout, providirig effective passage for vehicles using the Scheme while

retaining the urban/residential environment of the road. The initial thoughts were

to have the combined cycletrack/footpath and the footway immediately adjacent

to the road but, given the number of existing utilities that impact on the potential

for tree planting, the amount of landscaping is optimised by retaining the

cycletrack and footways on the existing alignments adjacent to the residential

premises. The ability to maximise the landscaping along this section of the route

was a key consideration from the feedback on the Scheme.

5.7.4. Consideration was also given to the ease with which pedestrians could cross the

road. Alternatives including a ful/ central reserve, a partial central reserve or no

central reserve were considered and the proposed option of a median strip with a

number of kerbed islands was considered to provide the optimum layout.

5.7.5. The inclusion of the median strip for much of the length of King Georges Road

provides an informal waiting space for pedestrians choosing to cross the road

whilst aI/owing residents to access their driveways as they currently do. It also

provides space for overtaking in the event of vehicles breaking down. The 1.5m

wide flush central reserve wil/ be finished in a contrasting coloured materiaL. This

colour contrast reduces the negative visual impact of a wider black macadam

surface although it can be overrun by vehicles.16


5.7.6. Formal pedestrian crossing points are provided at regular intervals along the road

via kerbed islands 2.0m wide. The islands have the appropriate dropped kerbs

and tactile paving with surface materials to match the central strip.

5.7.7. The proposed layout is considered to optimise the layout by making provision for

those who wish to cross the road and access driveways, while retaining an

appropriate width for vehicles using the Scheme.

5.8. Reserved Corridor

5.8.1. This section of the scheme is approximately 600m in length and runs through a

corridor that has been reserved for the route. The route wil/ be at grade to limit

the impact on adjacent property.

5.8.2. In the northern half of this sub-section the alignment of the Scheme is highly

constrained by adjacent premises, but as the route moves towards Hareclive

Road the corridor widens.

5.8.3. As a result of the stakeholder engagement exercise, an opportunity was taken to

further consider improvements that could be made with respect to severance.

5.8.4. Alternatives were considered in terms of where to locate the Scheme within the

corridor. A more curved alignment was favoured in order to help reduce vehiclespeeds and improve safety. This also aI/owed the avoidance of significant

underground water storage tanks. As with King Georges Road, consideration

was also given to the cross-section of the road through this sub-section. As more

width is available it was concluded that the introduction of a wide central reserve

in the southern half would be preferable, splitting the carriageway and hence

reducing the perception of the width of carriageway. A shared footway/cycleway

runs paral/el and adjacent to the north side of the carriageway. The footway

along the south side of the corridor deviates away from the carriageway where

the corridor is wider.

17


5.8.5. The planted central median helps to break up the dominance of the road through

this existing publical/y accessible green corridor. The median wil/ contain park

style/ornamental shrub planting and semi mature trees. It also provides a central

median for pedestrian crossing facilities linking the residential areas on either

side of the reserved corridor. Within the central median two crossings will be non-

signalised and one wil/ be signal control/ed.

5.8.6. Where the footway is not adjacent to the westbound carriageway, kerbs will be

splayed and the grass verge wil/ be reinforced to al/ow broken down vehicles to

pull off the road.

5.8.7. The proposed route is considered to provide good connectivity across the

Scheme.

5.9. Hareclive Road junction to Cater Road Roundabout

5.9.1. This section of the scheme is approximately 300m in length and runs through a

corridor adjacent to residential property on the south side and retaillcommercial

property to the north. The route wil/ be at grade to limit the impact on the adjacent

property.

5.9.2. The stakeholder engagement exercise identified opportunities relating to

accessibility for pedestrians, particularly at the junction with Hareclive Road, and

access to the commercial premises to the north.

5.9.3. The evaluation of this section of the Scheme therefore focussed on the footprint

of the junction with Hareclive Road and this has been significantly reduced. The

proposed roundabout has been replaced with a traffic signal control/ed junction,

greatly improving the connectivity for pedestrians.

5.9.4. As with the route alignment at Highridge Common, the alignment of the Scheme

has been kept, as far as possible, on the alignment of the existing road to

maximise the opportunities for 'greening' the remaining corridor.

18


5.9.5. From the new signalised junction at Hareclive Road, the Scheme extends

eastwards on a realigned section of Whitchurch Lane. This wil/ connect the

Scheme to the existing Cater Road roundabout. Access to existing commercial

properties wil/ be provided by the use of a median strip to al/ow turning without

causing a blockage, improving traffic flows in this area.

5.9.6. Existing footways are present on either side of Whitchurch Lane in proximity to

the Hareclive Road junction. These footways wil/ be re-provided as part of the

realignment proposals for Whitchurch Lane. These wil/ feed into pedestrian

crossing points on all arms of the new Hareclive Road traffic signals.

5.9.7. Two new signal controlled crossings will aid the crossing of Whitchurch Lane for

access to the superstore.

5.9.8. The Scheme wil/ terminate at the Cater Road roundabout, with vehicles able to

connect to the existing highway.

6. The Major Junctions

6.1 . Although no objections have been received that relate to the form or layout of the

junctions, this section of my proof of evidence provides a brief summary of the

rationale behind the junction design and the options considered for the major

junctions. The size and capacity of the junctions in each case is general/y

constrained by the single carriageway layout of the Scheme. The layouts of the

junctions with Highridge Road and Queens Road are also heavily influenced by

the existing built frontages.

6.2. The rationale for the designs has been developed from a consideration of four

factors as fol/ows:

i. Junction footprint I land requirement

ii. Pedestrian / cyclist provision

iii. Traffic handling capacity / congestion

iv. Route choice

19


These factors are independent but can be conflicting and hence a holistic view

has to be taken to determine an optimum balance for each junction. For example,where aI/ traffic movements are catered for at a junction, the 'footprint' increases

which in turn impacts upon severance and urban realm characteristics.

Simplifying the junctions enables the junctions to operate on a lower cycle time,

which increases the number of times a crossing can be activated and reduces

the time pedestrians and cyclists have to wait.

6.3. In order to maintain capacity at the junctions while providing optimum pedestrian

facilities and reduced junction footprints, it was necessary to restrict certain

movements through some of the junctions. This, however, was only considered

where convenient alternative routes choices were available. Where movements

have been restricted these are described under each junction below.

6.4. Traffic flows used to assess aI/ the junction layouts were obtained from the

SATURN traffic model of the area. The development and local improvement of

this model in the relevant area is described in the evidence given by Robert

Thompson (NSC/3/1).

6.5. A370 Roundabout

Design objectives

6.5.1. A key objective of the layout design here was achieving a vehicular capacity

adequate to meet the expected Opening Year (2016) and Design Year (2031)

weekday peak hour forecasts. This was in recognition of the fact that the A370 is

a key radial route intolout of Bristol from/to the South West.

Options considered

6.5.2. The options considered drew on earlier work which proposed an at-grade

roundabout junction with the A370, and which included a segregated left turn

lane from the A370 (westbound) approach to the Scheme. The position and

layout were governed by:

20


i. The Desirable Minimum Stopping Sight Distance (DMSSD) to the 'give way'

line on the A370 westbound approach (from Bristol).

ii. The abutment to an existing accommodation bridge over the A370 to the

west of the B3128 interchange, which dictates the closest position the

roundabout can be whilst satisfying the DMSSD, and

iii. the desire for no works encroachment to the north of the existing kerb-line of

the A370.

6.5.3. Further fine-tuning and lane layout/geometric changes were introduced as

fol/ows:

i. The diameter of the roundabout was increased to ensure aI/ roundabout

approaches were ful/y compliant with standards

ii. The termination of the segregated left turn lane was changed from a 'give-

way' to a lane gain / merge arrangement on account of predicted flows and

the consideration of operational and safety factors

Junction performance

6.5.4. The operation of the junction from a traffic perspective is presented in the proof of

evidence of Robert Thompson (NSC/3/1).

Other factors

6.5.5. Given the nature of the A370 and the location of the junction, no specific crossing

provision is built into the layout for pedestrians and cyclists. The footway/cycle

route along the Scheme deviates from the road at Longmoor Brook overbridge

and connects to the 'Festival Way' cycletrack to the north of the A370 by way of

the existing accommodation bridge.

6.5.6. Specific bus priority measures are not considered necessary at this junction as a

dedicated bus link is provided to the Park and Ride site from the Brookgate

junction, as discussed below.

21


6.6. Brookgate

Design objectives

6.6.1 . The main objectives of the Brookgate junction with the Scheme are to:

i. Enable a bus link connection to the western end of the proposed Ashton Vale

to Temple Meads Metrobus scheme and then to the Long Ashton Park and

Ride site; and

ii. Provide an alternative access to Brookgate and South Liberty Lane,

expressly to improve connectivity to the industrial units and to remove some

of the traffic associated with the industriallcommercial premises along these

roads from the residential streets to the north.

Options considered

6.6.2. Two signal/ed junction alternatives were considered, the only difference between

them being the treatment of the bus lane termination on the northbound Scheme

approach. Option 1 considered a signal/ed pre-signal termination at the end of

the bus lane, enabling a bus requiring a lane change to move over with other

northbound traffic held. Option 2 omitted the bus pre-signal, thus requiring buses

to make this lane change unassisted. The assessment concluded that the lane

change for buses would not be difficult given the expected volume of right turners

to either Brookgate or the bus link. In view of this the Option 2 solution was

adopted. The options are il/ustrated in Appendix 7 in NSC/2/2.




Other factors

6.6.4. An uncontrolled crossing point over the Brookgate link is included to

accommodate the pedestrian/cycle route on the east side of the Scheme. As22


there is no footway on the western side of the Scheme, there is no need to

include control/ed crossing facilities over the main alignment at this junction.

6.6.5. Southbound Metrobus services and other buses routing from the Long Ashton

Park and Ride site have a dedicated signal/ed bus link connection into the

junction. Southbound detection on this link can be arranged to provide a priority

bus demand as necessary. On the northbound Scheme approach most if not all

buses wil/ require a right turn to the bus link and, as such, Selective Vehicle

Detection using advanced detection wil/ be used to provide priority. Buses

continuing northbound on the Scheme to the A370 junction are unlikely to need

priority as the green time available to this movement wil/ be satisfactory.

6.7. A38 Bedminster Down Road

Design objectives

6.7.1. Achieving necessary traffic capacity at this key junction with the A38 was the

prime consideration, to al/ow good traffic flow for users using the whole length of

the Scheme and particularly for those using the section between the A370 and

A38 to avoid congestion along the existing routes via Winterstoke Road or

through Barrow Gurney.

6.7.2. Other location constraints are as follows:

i. The existing position of Winford Bridge, where Colliter's Brook passes under

the A38;

ii. The proximity of Castle Farm and its immediate curtilage to the west of the

junction; and

iii. Old lime kilns located just south of the A38.

Options considered

6.7.3. Two different layout options were considered for this junction, a signal/ed

roundabout (Option 1) and a traffic signal control/ed cross-roads (Option 2).

These are il/ustrated in Appendix 8 in NSC2/2. The signal/ed roundabout was23


shown to operate much better in capacity terms. The high predicted right turn

flows from the Scheme southbound to the A38 made a signal/ed roundabout

approach appriopriate, particularly as two lane provision was deemed necessary

for the southbound right turn from the Scheme.




Other factors

6.7.5. The proposed signalled roundabout layout includes controlled Toucan crossing

facilities over the A38 (eastern) entry and exit, thus providing safe passage

across the A38 for pedestrianslcyclists using the footway/cycleway along the

north/east side of the Scheme. Controlled crossing facilities are also

accommodated on the Scheme (northern) arm to allow access tolfrom the

northbound Metrobus platform stop.

6.7.6. The footway route along the south side of the A38 is maintained by uncontrol/ed

crossing points of the Scheme as pedestrian usage of this footway is very low.

6.7.7. On the southbound Scheme approach the bus lane is extended through to the

roundabout entry, with a separate signal or 'bus gate' used to give a right of way

for buses entering the junction. This al/ows safe 'priority' access to be given for

buses proceeding along the Scheme, or those services turning right onto the

A38. Advance detection could be used to give an early 'priority' cal/ for

southbound buses, although the platform stop and thus potential for stopping

makes the provision of a stop-line 'cal/' loop more appropriate.

6.7.8. On the northbound approach 'Selective Vehicle Detection' could be used to

provide a bus priority cal/ in this direction. The signalling at the roundabout and

the fact that the Metrobus platform stop in this direction is on the exit side makes

this feasible.

24


6.7.9. The existing access onto the A38 from Castle Farm is retained. The access track

from the north east corner of the farm curtilage is maintained, and a new 'cross-

over' to fields east of the Scheme provided just north of the northbound Metrobus

platform stop. This 'cross-over' occurs beyond the localised junction widening to

reduce the crossing width to the minimum afforded by the link design for this

section of the Scheme.

6.8. Highridge Road

Design objectives

6.8.1 . The key objective was to develop an adequate junction layout whilst minimising

the land-take required from Highridge Common. Another issue was maintaining

safe access to the existing garage and forecourt on the Highridge Green

approach, notably for drivers making the right turn in but also assisting egress for

those attempting the right turn out. As with the other Scheme junctions on the

route section through Bishopsworth, there was also a clear desire to achieve a

high level of se Nice for pedestrians and cyclists.

Options considered

6.8.2. Two different layout options, illustrated in Appendix 9 in NSC/2/2, were

considered for this junction. Minimising land-take from Highridge Common and

providing convenient crossing facilities for pedestrians meant that a signal

controlled layout was the obvious choice. Both options considered incorporate

control/ed pedestrian crossing facilities on all arms. However, Option 1 does this

using a 'split' or 'staggered' crossing with intermediate islands on the two

Highridge Road arms, whilst the other option uses 'single' crossings on all arms.

The latter option had the benefit of a lower land take, but the level of

convenience and level of se Nice afforded to pedestrian users of the junction was

much less. In view of this, the Option 1 layout was the one taken forward.

6.8.3. In determining this layout it was concluded that two movements should be

restricted. These are the left turn from Highridge Road into King Georges Road

and the right turn from King Georg8s Road into Highridge Road. The alternative25


route for the left turn ban is to turn right at the Queens Road junction and is only

likely to be used as access for residents of King Georges Road from the North.

The right turn from King Georges Road is another lightly trafficked movement,

which can be facilitated more directly by the current route of turning right at the

Whitchurch Lane junction.




Other factors

6.8.5. The design makes provision for controlled pedestrian crossings on aI/ four

junction arms; with the facility across the Highridge Road (N) arm catering for

cyclists as welL. The layout of the junction, with the intermediate islands on the

two Highridge Road arms, al/ows aI/ crossings to operate on a 'walk with traffic'

basis, thus minimising potential wait times for pedestrians.

6.8.6. Signalling at this junction al/ows 'Selective Vehicle Detection' to be employed as

previously described. The Metrobus platform stops are sited on the two Scheme

exits, this being the ideal situation in that any buses making a priority request

pass through the stop-line first before stopping.

6.8.7. The proximity of surrounding properties meant there were a number of local

access issues to consider in developing the layout. These were as fol/ows:

i. Access to/from the local garage on the Highridge Green approach, which is

very close to the stop-line, was a key consideration. A short waiting bay and

'Keep Clear' zone was included during the option assessment, although this

had the effect of shortening the length of the right turn lane available for

traffic on the Highridge Green approach. Traffic model/ing showed that this

was acceptable in the Opening Year (2016), but by the Design Year (2031)

there was a risk that the longer expected queue of vehicles turning right at

the main junction may simply choose to queue back across this 'bay', rather26


than impede ahead and left turning traffic. As such, lengthening the right turn

lane and introducing a yel/ow box marking was included in the Scheme for

which planning approval has been granted;

ii. The driveway access from No 83 is within the junction, which is unavoidable.

Consideration was given to providing a separate signal and 'cal/' facility to

al/ow vehicles leaving this driveway to exit easily. However, the safety

problem with this was that any signal for this driveway mounted, say, on the

adjacent central island, might easily be seen and misconstrued by a waiting

driver at the King Georges Road stop-line. In view of this and, as presently

proposed, a driver attempting to exit this driveway would do so in one of the

available inter-stage periods, or a suitable 'gap' in traffic flow during one of

the three signal stages; and

iii. Access to/from the driveway to No 80 was affected in earlier layouts by the

traffic island on the Highridge Road (eastern) approach. This was

subsequently shortened to enable the right turn in.

6.9. Queens Road

Design objective

6.9.1. The objective was to establish a junction with satisfactory capacity, while

recognising the numerous constraints imposed by the existing layout. Constraints

are imposed by frontage development, notably the Queens Head Public House

(PH) in the south-west corner. Taking land from this corner would require

demolition of the public house and accordingly this constrained the type of

junction possible. An existing private access to a club on the east side of Queens

Road was also a key constraint, insofar as this was very close to the proposed

junction, and thus affected how the south-east corner of the layout could be

arranged. The layout of the south-east corner was also significantly influenced by

the presence of a large underground Wessex Water tank.

Options considered

6.9.2. Two different layout options were considered for this junction, as illustrated in

Appendix 10 in NSC/212. The only difference between the two options was the27


addition of a control/ed crossing on the King Georges Road arm with Option 2.

However, in view of sub-standard inter-visibility across the south west corner it

was decided not to increase risk by adding a crossing on the west side. Option 1

was therefore the proposed layout.

6.9.3. In developing this layout it was decided to restrict four movements. From Queens

Road the right turn is not available. The alternative is a right turn onto

Gatehouse Lane followed by the South to East movement identified in the

Hareclive Road scenario below. From the north of Queens Road the left turn has

been restricted, but the more direct route is along Whitchurch Lane. Travel/ing

from the East the left and right turns are both prohibited, with the alternatives

being routes at the Hareclive Road junction discussed below.




Other factors

6.9.5. Control/ed pedestrian crossings are incorporated on three arms of the junction, a

Toucan type provided at the northern crossing on the shared footway/cycle route.

Proposed vehicle turning restrictions have the advantage of providing a

considerably enhanced level of service for pedestrians using the crossing over

the Scheme on the east side of the junction.

6.9.6. Signalling the Queens Road junction al/ows 'Selective Vehicle Detection' to be

used on the Scheme approaches. In consideration of the existing frontage

development the westbound Metrobus stop has been located to the east of the

junction.

6.9.7. The proximity of the Queens Head PH, and also the vehicular access to the club,

means that frontage access was a key factor at this junction. Access for

deliveries to the public house is via a small yard with an entrance just west of the

junction on King Georges Road and this wil/ be retained.28


6.10. Hareclive Road and Whitchurch Lane

Design objective

6.10.1. The key objective was to minimise the size or 'footprint' of the Hareclive Road

junction. It was also considered important to provide a high level of service for

pedestrians, given the key desire line for local pedestrian movement between

Hareclive Road and the Lidl foodstore on the north side of Whitchurch Lane. It

was considered that the junction should offer an adequate level of capacity to

deal with expected traffic flows in both the Opening Year (2016) and Design Year

(2031) while keeping 'wait times' to cross the Scheme low to minimise

inconvenience.

Options considered

6.10.2. Four different layout options, and some sub-options, were considered for this

junction, as shown in Appendix 11 in NSC2/2. The proposed option emerging

from these assessments was Option 3A, which incorporated the following design

developments:

i. The Scheme/Whitchurch Lane junction was signal/ed;

ii. The former alignment of Hareclive Road north of the new Scheme junction

was retained, and hence the existing priority junction with Whitchurch Lane.

However, unlike the previous Option 3 layout the traffic movements on

Whitchurch Lane are now 'controlling', with drivers on the Hareclive Road

approach required to 'give way'; and

iii. Local bus stop provision was added to the section of Hareclive Road to the

north of the new Scheme junction. The existing southbound bus stop is

directly affected by the new junction, so required re-location. The northbound

stop was retained in its existing position. Half-width lay-bys were introduced

to reduce potential exit blocking in the northbound direction, and to prevent

southbound passage to the stop-line being prevented by a stopped bus

during the green phase for Hareclive Road.

29


6.10.3. The adoption of this layout was considered to best achieve the design objectives

of reducing the footprint of the junction and providing a high level of service for

cyclists and pedestrians.

6.10.4. The Hareclive Road junction was therefore designed as predominantly ahead

movements only. This is satisfactory as there are alternative network options.

6.10.5. When travel/ing from the East a route to the South can be achieved via a slight

detour. Firstly a right turn onto Whitchurch Lane then left onto Hareclive Road,

where you then proceed ahead at the Hareclive Road junction. East to North is

achieved turning right onto Whitchurch Lane before the Hareclive Road. The

East to West movement proceeds using the ahead movement.

6.10.6. Approaching the junction from the South the left turn was provided to minimise

the 'rat running' along Gatehouse Avenue. The South to North movement is

facilitated through the junction. Travelling South to East is as per the North route,

with a right turn onto Whitchurch Lane fol/owed by a left at the Whitchurch Lane

junction.

6.10.7. Vehicles approaching from the West wanting to head southbound would need to

make a right turn at the Queens Road junction and use Gatehouse Lane or

alternatively a left at Queens Road or Highridge Road junction accessing

Whitchurch Lane and then Hareclive Road.

6.10.8. Vehicles from the North of the junction travel/ing East would use Whitchurch

Lane as per the current arrangement. Traffic heading southbound would opt for

Hareclive Road much as they do now. Vehicles wanting to turn right to access

the new road could choose from a right turn at the Queens Road junction or at

Highridge Road.




30


Other factors

6.10.10. The junction with Hareclive Road has control/ed pedestrian crossing facilities on

aI/ four junction arms. The crossing on the northern Hareclive Road wil/ also be a

Toucan type, thus aI/owing use by cyclists as part of the shared use

footway/cycle route on the north side of the Scheme. The control of the traffic

signals wil/ provide long 'green man' times at aI/ crossings, due mainly to the

prohibited turns introduced which in turn enable a very simple method of control

and 'walk with traffic' pedestrian crossing provision. Control/ed crossing facilities

are also included at the SchemelWhitchurch Lane junction, with the crossing over

Whitchurch Lane again catering for the cycle route.

6.10.11. The importance of the Scheme as a Metrobus route needed to be considered in

defining the junction type here, and in particular how 'priority' could be ensured

for the new Metrobus services. Signal/ing at both the junctions wil/ al/ow

'Selective Vehicle Detection' to be used on the Scheme approaches, thus

permitting equipped buses to make a 'priority' cal/ for the signal stage in which it

gets green, or extending this stage to al/ow passage of the bus through the stop-

line if it is already running. The Metrobus platform stops are sited downstream of

the stop-lines at Hareclive Road to ensure that any buses making a priority

request do pass through the stop-line before stopping.

7. Minor Junctions and Accesses

7.1. As part of the Scheme development, the need to provide access to various

adjacent land holdings and minor roads was considered. The provision was

discussed with individual landowners and the results are summarised below

under the same sections as used for the discussion on the alignment above.

7.2. The locations of the minor junctions and accesses and the chainages (distances

along the road) referenced below are shown on the drawings included in

Appendix 3 in NSC/2/2. References to right and left are considered when viewed

in the direction of increasing chainage.

31


7.3. The consideration of the interaction between the Scheme and the Public Rights

of Way is considered in the proof of evidence of Elaine Bowman (NSC/11/1).

7.4. A370 to Network Rail Underbridge (Appendix 3A and Appendix 3B in NSC/2/2)

7.4.1. Individual field accesses have been provided, as requested by the tenant farmer,

at chainage 220 (to the right) and chainage 510 (both sides). The latter have

been located at field boundaries and provide access in both directions.

7.4.2. Connectivity for moving livestock and for the passage of light vehicles has also

been provided beneath the Scheme at Longmoor Brook Underbridge.

7.4.3. Maintenance access for the Environment Agency and Network Rail has been

provided from the link road to Brookgate. During discussions with Network Rail a

preference for laybys directly off the Scheme was expressed and it is the

intention to provide these, with a consequent reduction in length of the

maintenance access, as il/ustrated in Appendix 12 in NSC/2/2.

7.4.4. The link road to Brookgate forms a priority junction with Brookgate, the priority

being given to vehicles moving to/from the Scheme.

7.5. Network Rail Underbridge to A38 (Appendices 3B and 3C in NSC/2/2) .

7.5.1. Two accesses have been provided to the landfil/ site directly from the Scheme at

chainages 1100 (right) and 1315 (right). These accesses, when used in

conjunction with the Scheme itself, are reasonably convenient alternatives to the

existing access track that is to be stopped up to al/ow construction of the

Scheme.

7.5.2. Provision for pedestrians to cross the road safely has been provided beneath

Colliter's Brook Underbridge.

7.5.3. Access to fields associated with Castle Farm has been provided at chainage

1850 (both sides).

32


7.5.4. Direct access has been provided from Castle Farm to the A38. It is intended that

this is a left out access only and that vehicles turning right to head in a southerly

direction on the A38 should initially turn left and then turn by way of the

roundabout. The secondary access to the farm/landfil/ site is to be stopped up

but a reasonably convenient alternative has been provided for the farm from the

retained primary access and the revised access arrangements for the landfil/ site

have been addressed in paragraph 7.5.1 above.

7.5.5. Direct field access has been provided to land south of the A38 on both sides of

the roundabout. To the west, a field access is to be stopped up but a reasonably

convenient alternative is to be provided at the same location. This access will

also be supplemented by a number of new direct field accesses from the Scheme

as described in paragraph 7.6.1 below.

7.5.6. Within the footprint of the new roundabout a private means of access to the south

of the roundabout is to be stopped up. A reasonably convenient alternative is to

be provided from an access at chainage 2195 (left). This was shown as a single

access as part of the Planning Application but has been adjusted under the

proposed Side Roads Order to provide access to two land holdings, as shown in

Appendix 13 in NSC/2/2.

7.6. A38 to Highridge Common (Appendix 3C and Appendix 3D in NSC/2/2)

7.6.1. Direct field accesses have been provided, at the request of the landowners, at

chainage 2195 (both sides), chainage 2305 (left), chainage 2375 (right),

chainage 2440 (right) and chainage 2460 (left). An access at chainage 2400 (left)

has been included in the proposed Side Roads Order fol/owing discussions with

the landowner.

7.6.2. At chainage 2740 (right) access is provided to the residential premises known as

Highridge Cottage. This is a reasonably convenient alternative to the existing

access that is to be stopped up.

7.6.3. At chainage 2780, a connector road is provided to link the Scheme to the existing

Highridge Green. Immediately to the south of this the existing HighridgeGreen is33


stopped up. The new connector road, when used in conjunction with the

Scheme, is a reasonably convenient alternative to the stopped up length of

Highridge Green.

7.6.4. It is proposed that the existing access to No. 139 Highridge Green be stopped

up. However, a reasonably convenient alternative is proposed alongside the

existing access and connecting to the retained length of Highridge Green.

7.6.5. Between this point and the junction with Highridge Road, access is retained to aI/

residential and commercial premises, with some of the accesses improved.

7.6.6. As part of the consultation process it was agreed that additional accesses be

provided to the residential premises at nos. 143, 177 and 183 Highridge Green.

These were included in the Side Roads Order and are il/ustrated in Appendix 14

in NSC/2/2.

7.7. Highridge Road to Queens Road - King Georges Road (Appendix 3D in

NSC/2112)

7.7.1. Minor junctions wil/ be retained to both Elmtree Drive and Broadway Road.

7.7.2. Access to aI/ existing residential and commercial premises wil/ be retained,

although roadside parking wil/ not be permitted in order to maintain traffic flows.

7.8. Queens Road to Hareclive Road - The Reserved Corridor (Appendix 3D and

Appendix 3E in NSC/2/2)

7.8.1. No vehicular access is required within this length of the Scheme.

7.8.2. Four existing footpaths are to be stopped up but these are aI/ to be replaced with

reasonably convenient cycletracks with rights of way on foot.

7.9. Hareclive Road to Cater Road Roundabout (Appendix 3E in NSC/2/2)

7.9.1. Access to aI/ commercial premises will be retained.

34


7.10 In conclusion, the construction of the Scheme wil/ affect a number of private

means of access as set out in the preceding paragraphs. However, in aI/ cases

reasonably convenient alternative means of access are proposed under the

Scheme.

8. Provision for Pedestrians and Cyclists

8.1. In developing the Scheme layout, due regard was taken of a number of

constructive suggestions received during the extensive consultation exercise.

These suggested improvements related to the fol/owing issues:

i. Connectivity to existing facilities

ii. Ease of passage along the route, with a preference expressed that the

combined cycletrack/footway should not cross from one side of the Scheme

to the other, and

iii. Transverse severance created by the introduction of the Scheme

8.2. Developments to the Scheme resulting from consideration of these issues were

as fol/ows:

i. At the northern end of the scheme, adjacent to the A370, the shared use

cycletrack/footway has been extended to connect to Festival Way.

ii. The shared use facility has also been provided adjacent to the bus link that

connects to the AVTM scheme, further improving connectivity.

iii. Diversions to existing Public Rights of Way (PROW) have been included

where appropriate and where possible these have been provided beneath

the proposed Scheme to reduce potential points of conflict. Examples are at

Longmoor Brook and Colliter's Brook underbridges and these are described

in the evidence of Elaine Bowman (NSC13/1).

iv. Footway provision at Brookgate has been revised to improve connectivity.

v. Along the entire length of the scheme the shared facility has been located on

the one side (to the north/east) greatly simplifying the longitudinal passage

for pedestrians and cyclists, particularly through the junctions.

35


vi. AI/ junction designs have been reviewed to improve the passage for

pedestrians, avoiding aI/-red phases wherever possible. Junction footprints

have been minimised to improve the connectivity for pedestrians.

vii. In King Georges Road, a median strip has been included to provide an

informal crossing facility along the length of this section. Five formal

pedestrian islands have also been included.

viii. In the reserved corridor, transverse connectivity has been maintained by

providing signalised and non-signalised crossing points. A wide median has

been included to facilitate the Grossing of the road in this area.

ix. The proposed roundabout at Hareclive Road has been replaced by a

signalised junction with a smal/ footprint, greatly improving connectivity

between the residential areas and the superstore.

8.3. The provision for pedestrians and cyclists is therefore considered to provide a

high level of service, the requirements for these users having been an integral

part of the Scheme development.

9. Scheme Engineering

9.1. In the fol/owing sub-sections I wil/ describe the engineering that underpins the

scheme layout. This wil/ be presented under a number of discipline sub-

headings.

9.2. Geotechnics

9.2.1. This sub-section provides a description of the key elements of the geotechnical

works associated with the Scheme, including comment on the crossing/treatment

of landfills. The final details of the geotechhical works are subject to detailed

design by the appointed Design & Build contractor.

Earthworks Slopes

9.2.2. Earthworks are generally intended to be constructed with 1:3 side slopes.

36


9.2.3. To permit construction of embankments on weak/soft foundation soils it is

envisaged that ground improvement wil/ be required. Where a limited thickness of

weak/soft soil is present then this can be excavated and replaced with

engineered fill. For areas where the thickness of weak/soft soils is too large then

alternative methods of ground improvement may be more appropriate.

Retaining Structures

9.2.4. Retaining structures are proposed for areas where limited space precludes the

use of 1 :3 earthworks slopes.

9.2.5. Sheet piled vertical retaining wal/s are to be provided on the north-west and

south-east approaches to Colliter's Brook underbridge. This is to avoid the large

scale re-alignment of Colliter's Brook, which would be required to accommodate

embankment side-slopes.

Ground Improvement

9.2.6. To avoid excessive excavation of weak/soft soils one or more of the fol/owing

ground improvement techniques could be employed:

i. Surcharge - suitable for soft al/uvial cohesive soils and could include use of

vertical drains to increase the rate of consolidation.

ii. Vibro-stone columns - may not be suitable in very soft cohesive soils.

iii. Soil mixing - feasibility wil/ depend on the suitability of the soils.

iv. Heavy compaction - dynamic compaction suitable in non-organic al/uvial

soils, alternatively use of an intelligent compaction system (e.g. Landpac)

may be suitable for achieving compatibility of stiffness between improved

soils and areas of build out embankment.

9.2.7. This is not an exhaustive list of potential ground improvement options and input

from a specialist contractor/supplier wil/ be required to arrive at an acceptable

design for any ground improvement option. I can, however, confirm that sufficient

land has been identified for these potential technical solutions.

Landfil/ Areas37


9.2.8. The alignment crosses three known areas of landfill, as illustrated in Appendix 6

in NSC/2/2.

i. Yanley 3 - construction is over an area of the landfil/ that has been

safeguarded so that it includes only inert fil/, which is composed of natural

materials excavated during construction of other landfill cel/s.

ii. Yanley 2 / Yew Tree - recent ground investigation indicates that the road

construction wil/ not encroach on this landfil/ area. In the event that the road

construction does impinge on the landfil/ then construction options are as

given below.

iii. Stones - construction will require a cut on the eastern side of the

carriageway and fil/ on the western side.

9.2.9. Construction options include:

i. Road on piled platform

ii. Excavate and replace with engineered fil/

iii. Heavy dynamic compaction fol/owed by placement of engineered fil/

9.2.10. This is not an exhaustive list of potential construction options and input from a

specialist contractor/supplier wil/ be required to arrive at an acceptable design for

crossing the landfil/s. I can, however, confirm that sufficient land has been

identified for these potential technical solutions.

9.3. Drainage

9.3.1. Drainage for the Scheme is considered under two headings, Flood Risk and

Surface Water Drainage.

Flood Risk

9.3.2. From a review of the Environment Agency Flood Maps it is apparent that the

route of the Scheme lies within Flood Zones 1, 2 and 3; and as defined by the

NPPF (CD2/6) the route of the Scheme may be concluded as having a low to

high probability of flooding. The Scheme is classified as 'Essential Infrastructure'.

38


9.3.3. The Environment Agency, Bristol City Council and North Somerset Council have

been consulted throughout the development of the Scheme. The Environment

Agency has not objected to the proposed Scheme subject to the discharge of a

number of conditions.

Flood Risk Assessment

9.3.4. The proposed route crosses areas of previously developed and undeveloped

land. Within the undeveloped land, the route passes through the

Ashton/Longmoor Brook and New Colliter's Brook floodplain and open farmland,

crossing several streams and unnamed drains. The watercourses in the vicinity

of the site have historical/y been subject to diversion and hydraulic improvement.

9.3.5. The watercourses directly affected by the proposed scheme are the

Ashton/Longmoor Brook, Colliter's Brook, New Colliter's Brook and the Malago,

as shown in Appendix 15 in NSC/2/2. In addition to these 'main rivers' there are

a series of ordinary watercourses and agricultural drainage ditches south of the

A38 which wil/ also be affected.

9.3.6. Appendix 16 in NSC/2/2 shows the proposed route and the Environment Agency

flood zones. The majority of the route (3.9km) lies within the Environment Agency

Flood Zone 1 (Iow probability of flooding, ~1 in 1 OOO-year flood event). Only

0.2km of the route falls within Flood Zone 3 (high probability of flooding, )0 1 in

1 OO-year flood fluvial event), and 1.1 km within Flood Zone 2 (medium probability,

between 1 in 1 OO-year and 1 in 1 OOO-year fluvial event). The majority of these

lengths are related to the Ashton/Longmoor Brook and Colliter's Brook,

particularly downstream of the Bristol to Taunton railway line. A smal/ proportion

of the proposed route also fal/s within Flood Zones 2 and 3 as it crosses the

Malago in Bishopsworth.

9.3.7. A detailed Level 3 Flood Risk Assessment (CD4/3-4/5) was developed in

accordance with the NPPF (CD2I26), the DMRB and relevant Environment

Agency and Local Authority guidance.

39


9.3.8. The principal aim of the Flood Risk Assessment and Drainage Strategy was to

maintain the existing hydrological behaviour as far is reasonably possible, and to

mitigate for detriment in line with the design principles stated below:

i. A 60-year scheme design life to 2072, with climate change impacts taken into

account for sea level rise (481 mm to 2072), rainfal/ intensity (30% increase in

peak rainfall intensities) and river flow (20% increase in peak flow);

ii. The standard of protection provided for new works from fluvial flood risk is

the 1 in 1 OO-year flood event, including climate change al/owance (and 0.6m

freeboard);

iii. Where required, compensatory flood storage provided for events up to the 1

in 1 OO-year flood event, including an al/owance for climate change;

iv. The Ashton Vale to Temple Meads (AVTM) hydrological and hydraulic model

would be used to assess the impacts of the proposed scheme on tidal and

fluvial flood risk along the Colliter's Brook and Ashton/Longmoor Brook. The

AVTM model had also been used to assess the impact of the proposed

Ashton Gateway development (Bristol City Stadium) adjacent to the AVTM

route. This ensured a consistency of approach and assessment of cumulative

impacts and mitigation measures between the three proposed schemes.

Impact of the route

9.3.9. The hydrological and hydraulic model tested the impact of the proposed schemeby including the fol/owing scheme elements: a new clear span bridge over

Ashton/Longmoor Brook, ground raising in the floodplain on the left bank of the

New Colliter's Brook, ground raising in the floodplain and channel realignment of

the Colliter's Brook (south of the railway line), and replacement of an existing

culvert across the Colliter's Brook with clear span bridge. Model results were

compared to the existing situation.

Mitigation Measures

9.3.10. The hydrological and hydraulic modelling demonstrated that mitigation measures

were required. The principle mitigation measures tested within the hydrological

and hydraulic model and proven to manage fluvial/tidal flood risk from the

scheme were:40


i. New bridge crossings designed as clear span structures with a minimum

soffit level above the 1 in 1 OO-year flood event (including an al/owance for

climate change) plus 0.6m freeboard;

ii. Road levels set to a minimum level of 1 in 1 OO-year flood event (including an

al/owance for climate change) plus 0.6m freeboard;

iii. A compensatory flood storage area between the New Col/iter's Brook and

Ashton/Longmoor Brook to mitigate for the loss of floodplain storage from the

proposed raised road embankment on the left bank of the New Colliter's

Brook. This wil/ provide an additional 15,000m3 of storage capacity and result

in betterment in flood risk;

iv. The proposed realignment of the Colliter's Brook adjacent to the Viridor site

will maintain current channel capacity to prevent any increase in flood risk;

v. A flow assessment was completed to ensure that the new culverts proposed

for the ordinary watercourses south of the A38 would be capable of providing

conveyance for a 1 in 1 OO-year flood event (including an al/owance for

climate change), with an additional 0.3m freeboard, in line with guidance from

the DMRB. New culvert lengths have been minimised where possible;

vi. Strengthening works to protect the existing culverts for the New Colliter's

Brook and the Malago from additional loadings caused by the proposed

route.

9.3.11. With these mitigation measures, which have been incorporated into the Scheme

for which Planning permission has been granted, the route does not increase

flood risk elsewhere.

Cumulative Impacts (Ashton Vale to Temple Meads and Ashton Gateway)

9.3.12. The Flood Risk Assessment considered a range of scenarios combining the

scheme with the AVTM and Ashton Gateway (Bristol City Stadium) proposed

developments, to test potential mitigation options to ensure that whichever

combination of developments (the Scheme, AVTM and Ashton Gateway)

proceed, mitigation options were effective at managing flood risk.

41


9.3.13. The hydrological and hydraulic model tests confirmed that sufficient flood storage

can be provided under all scenarios to avoid an increase in flood risk.

Planning Requirements

9.3.14. The Flood Risk Assessment demonstrated that the proposed scheme passes the

Sequential and Exception Tests, in accordance with the NPPF, in terms of

providing wider sustainability benefits to the community that outweigh flood risk.

Conclusion

9.3.15. The Flood Risk Assessment and Drainage Strategy developed in consultation

with the Environment Agency, North Somerset Council and Bristol City Council

concluded that the Scheme has a good level of protection against flooding

(general/y better than a 1 in 1 OO-year flood event plus climate change), and

demonstrated that the development wil/ be safe for its lifetime.

9.3.16. The proposed mitigation works ensure that the route does not increase flood risk

elsewhere.

Surface Water Drainage

9.3.17. The drainage strategy has been developed in accordance with the guidance set

out in the NPPF (CD2/16). As such consideration has been given to the

management of surface water discharge from the proposed highway, with

comparison between preand post development surface water run-off rates

associated with the rural and urban elements. This has resulted in an outline

sustainable drainage system aimed at reducing the rate of surface water

discharge from the site, whilst giving due consideration to climate change.

Site Description with Regard to Surface Water Management

9.3.18. The route of the Scheme passes through undeveloped farmland and the south

Bristol suburb of Bishopsworth, and hence consideration has been given to

assessing both greenfield and brownfield surface water runoff rates in the42


development of a sustainable drainage system, whereby consideration has been

given to flood reduction, pollution reduction, biodiversity and the local community.

9.3.19. The site in which the Scheme is to be constructed encompasses a number of

streams and unnamed drains and a flood plain, which have been considered in

the development of the sustainable drainage strategy to ensure their

performance is not compromised by the scheme.

9.3.20. Due to the extent of development within the south Bristol suburb of Bishopsworth

there has been limited opportunity to develop a sustainable drainage strategy

with respect to both the col/ection of surface water runoff and its disposal in a

sustainable manner.

9.3.21. The route of the Scheme encroaches into the landfil/ site operated by Viridor and

requires the repositioning of two of their surface water balancing ponds; the

waste has been clarified as being inert, however the new detention basins and

cut-off ditches are to be lined with an impermeable membrane in this vicinity.

9.3.22. The site is influenced by the surface water runoff from a number of existing roads

which merge with the proposed Scheme; the drainage strategy has been

developed to intercept the runoff from adjoining roads, in particular Queens Road

where surface water runoff is believed to contribute to flooding.

9.3.23. To control pluvial flow routes in the areas of open farmland consideration has

been given to the incorporation of a number of cut-off drains to be constructed

within the highway boundary. These ditches will divert existing overland flows to

their pre-development destination while protecting embankments and cuttings

from run-off from external catchments.

9.3.24. The ground conditions general/y comprised clay overlain by made ground to a

depth of around 1 metre in some locations, and thus there is considered no

opportunity to discharge surface water directly to the underlying groundwater

regime due to the impermeable nature of the sub-strata. The investigation also

informed that the groundwater level was typical/y high and in one instance was

perched and believed to have a potential artesian head. This data has been used43


to develop the detention basins proposed to support the sustainable drainage

strategy.

Consultation

9.3.25. Consultation has taken place with, amongst others, the Environment Agency,

North Somerset Council, Bristol City Council, Viridor Waste Management Ltd and

Wessex Water.

Surface Water Drainage Strategy

9.3.26. A number of drainage catchments have been determined based on a

consideration of the vertical alignment of the road. These catchments, referenced

A to M, are summarised in Appendix 17 in NSC/2/2.

9.3.27. Catchments A to H are categorised as greenfield catchments as they currently

comprise open farmland. The attenuation facilities promoted in the design have

been sized to control a 1 in 100 year site discharge to less than or equal to 1 in

100 year greenfield peak runoff rates. It should be noted however that DEFRA &

EA (2005) suggests that a practicable minimum limit of 5 lIs should be applied to

the discharge rate to keep the risk of blockage to an acceptable leveL. Where the

greenfield rate for the catchment is calculated as below 5 lIs, this practicable

minimum limit has been applied.

9.3.28. Catchments J to M are categorised as brownfield catchments as they lie within

the urban area of BristoL. As Lead Local Flood Authority, Bristol City Council has

requested that wherever possible the designated brownfield catchments should

be assessed with respect to discharge rates and associated volumes on the

same basis as for greenfield catchments to provide a degree of betterment within

the south Bristol suburb of Bishopsworth. The stipulated requirement is

achievable for catchments K and L, however for catchments J and M, where

there is limited space available for either a detention basin or underground

storage tank, it is not a viable option, and thus a degree of betterment over the

pre-development runoff rates has been agreed. BCC has agreed that the

44


drainage strategy for catchment J should result in 30% betterment over the pre-

development runoff rates.

9.3.29. In determining an acceptable degree of betterment for catchment J, in

consultation with BCC, it has been established that flooding occurs on a regular

frequency in the vicinity of Queens Road. To mitigate the ongoing flooding issues

in Queens Road in the immediate vicinity of the proposed Scheme it has been

agreed with BCC that an element of the runoff from Queens Road be intercepted

as part of the Scheme. The extent of the runoff from Queens Road to be

intercepted is subject to confirmation as part of the detailed design.

9.3.30. For catchment M, the current highway drainage system serving the roads in the

catchment is to be replaced to serve the proposed Scheme; however as the

distance between the proposed outfal/ location at Pigeon house Stream Lake isapproximately 330m from the proposed catchment, it is proposed to utilise

Wessex Water's surface water sewer to convey flows from the highway drainage

network to the lake. This discharge has been agreed in principle with Wessex

Water.

9.3.31. An al/owance for climate change has been made, with rainfal/ figures increased

by 30% in accordance with normal practice, as set out in NPPF (CD2/16).

9.3.32. The selection of an outfal/ has been based on the fol/owing order of preference:

i. Infiltration

ii. Discharge to watercourse

iii. Discharge to surface water sewers

As the underlying impermeable strata mean that infiltration is not possible,

discharge to watercourse is the preferred method. While this can be achieved for

all catchments, for catchments H and M the most practicable watercourse

connection requires use of lengths of Wessex Water surface water sewers.

45


Attenuation Facilities

9.3.33. In order to maintain the rate of runoff to original greenfield runoff rates, whilst

giving due consideration to climate change, attenuation of flows from the

development is necessary. The proposed methods include attenuation basins,

tank sewers and attenuation tanks and the method for each catchment is listed in

Appendix 17 in NSC/212.

Drainage Network

9.3.34. The col/ection of surface water flows from the carriageway is to be in accordance

with the details contained in the DMRB documentation. It is proposed to use a

positive gravity drainage system, with gul/eys associated with the kerbs and a

carrier pipe system to carry the surface water to the attenuation facilities.

9.4. Structures

9.4.1. The form of the proposed structures has been selected to address a number of

factors including the site constraints, stakeholder requirements, construction cost,

maintenance requirements and aesthetics. A brief description of the individual

structures is included below.

Longmoor Brook Bridge (Ch. 296m)

9.4.2. This bridge structure is required to convey the Scheme over the existing

Longmoor Brook watercourse and a proposed 2.4m wide pedestrian and

livestock path on the east bank of the watercourse. The structure comprises a

single span of approximately 12.5m with adjacent concrete wingwal/s to retain

the highway embankment. The bridge superstructure is formed from a series of

precast concrete beams which are placed in position by crane and then made

structural/y continuous with each other via an in-situ reinforced concrete deck

slab. This form of bridge permits rapid construction with minimal impact on the

watercourse. In line with current industry best practice, the bridge deck is made

ful/y integral with its supporting abutment wal/s, as the elimination of bridge

bearings and movement joints significantly reduces the future maintenance works46


associated with the bridge. The structure wil/ be supported on piled foundations,

carrying the loads through the al/uvium present at the site to the underlying

Mercia Mudstone rock. A general arrangement drawing of the structure is

included in Appendix 18 in NSC/212.

Bridge over Colliter's Brook Armco Culvert

9.4.3. This structure is located on a proposed access road linking the Scheme (at an

approximate chainage of 730m) and the Ashton Vale Trading Estate. The

proposed access road crosses the existing Colliter's Brook watercourse at a

location where the brook is conveyed within an Armco culvert, a corrugated steel

culvert structure buried approximately 1.2 metres below existing ground leveL. In

the absence of information regarding the strength of the existing culvert structure

it is proposed to construct a concrete slab spanning over the existing culvert,

supported on a row of piles on each side of the culvert. This provides a robust

structure which ensures that the existing culvert is not subject to any increase in

load from the proposed access road. A general arrangement drawing of the

structure is included in Appendix 19 in NSC/212.

Colliter's Brook Bridge (Ch. 1515m)

9.4.4. This structure carries the Scheme over the existing Colliter's Brook watercourse

and a proposed 1 .8m wide footpath on the north bank of the watercourse. The

structure comprises a single span of approximately 13m with adjacent concrete

wingwal/s to retain the highway embankment. The form of the structure is as

described above for Longmoor Brook Bridge, since this form again offers an

efficient method of construction and provides a durable structure. A general

arrangement drawing of the structure is included in Appendix 20 in NSC/2/2.

Colliter's Brook Retaining Wal/ - North (Ch. 1420m to 1490m) and Colliter's

Brook Retaining Wal/ - South (Ch. 1528m to 1683m)

9.4.5. Two retaining wal/s are required on either side of Col/iter's Brook Bridgewhere

the proximity of Colliter's Brook prevents the construction of standard highway

embankments. It is proposed to construct the wal/s from steel sheet piles driven47


into the ground as these will provide protection to the highway against any future

scour. A concrete capping beam wil/ be cast around the tops of the steel piles

and the front face of the wal/s below the capping beam wil/ be clad in a material

with the appearance of natural stone. General arrangement drawings of thestructures are included in Appendix 21 in NSC/2/2.

Bridge over Malago Culvert (Ch. 3572m)

9.4.6. The structure is proposed where the Scheme crosses the confluence of the River

Malago and a tributary watercourse, where both watercourses are conveyed

within buried concrete culverts. In the absence of structural records for the

existing culverts a piled overspanning slab is proposed, similar to that described

above for the structure over Colliter's Brook Armco Culvert and with the same

objective of ensuring that the Scheme does not impose any additional load on

the existing culverts. A general arrangement drawing of the structure is included

in Appendix 22 in NSC/2/2.

Culverts

9.4.7. A series of culverts are required beneath the Scheme main carriageway and

associated link roads, ten of which require clear spans in excess of 0.9m. These

ten larger culverts wil/ be constructed using a series of standardised precast

reinforced concrete box sections laid adjacent to each other on a granular

bedding. At the upstream and downstream ends, the culvert wil/ terminate at an

in-situ reinforced concrete headwal/ with adjacent wingwal/s at 45 degrees to the

alignment of the watercourse. An integral mammal ledge will be incorporated

within the culvert box segments at locations where this is deemed necessary for

safe mammal passage.

9.5. Street Lighting

9.5.1. The requirement for street lighting arises from a consideration of safety. For the

project there are two distinct sections, the rural length within North Somerset and

the urban length within the Bristol City boundary.

48


North Somerset Area

9.5.2. Given the rural context of this length of the road and the environmental

constraints, such as Ashton Court, only the areas in the vicinity of the junctions

are to be lit. This fol/ows the principles set out in Guidance Notes for the

Reduction of Obtrusive Light (GN01 :2011). The extent of the lighting to be

provided in these areas is defined as being over a stretch long enough to provide

about 5 seconds of driving distance leading into or away from conflict areas at

the expected traffic speed (Lighting of Roads for Motor and Pedestrian Traffic

CIE 115:2010 - Chapter 8: The Lighting of Conflict Areas). Conflict areas are

typical/y junctions, intersections, roundabouts and pedestrian crossings, where

significant streams of motorized traffic intersect with each other or with other road

users such as pedestrians and cyclists. Where a 40mph speed limit is in place

this equates to a distance of 90 metres.

9.5.3. The lighting levels for traffic routes are set out in BS 5489 Part 1 2013 Table A.2

& A.3 and are dependent on the type of road, the amount of traffic and the

environmental classification. For this section of road the type of road is classified

as a single carriageway traffic route with either speed ;:.40mph or :5 40mph, the

traffic volumes have been derived from the traffic model for the scheme and the

environmental classification has been that appropriate for National Parks and

areas of outstanding natural beauty in rural areas (class E1). These lighting

levels are only required at peak times and wil/ be dimmed at other timesby using

predetermined settings in the luminaires. The luminaires that are to be used have

no light above the horizontal, minimizing light spil/age and sky glow.

Bristol City Area

9.5.4. Given the urban nature of the length of the Scheme within the Bristol City area,

the entire length wil/ be lit from Highridge Green through to Cater Road

roundabout. The lighting wil/ be by long life LED lanterns and wil/ be control/ed

via a management system that wil/ enable lighting levels to be changed as and

when required to react to changing traffic flow and weather conditions. The

lighting for the roads and junctions has been designed to an ME3 standard as a

minimum and pedestrian areas to S3/S4 as a minimum. Columns wil/ be49


standard conical columns and the heights wil/ vary between 10 metres and 8

metres for the carriageway areas and 6 metres where supplementary columns

are required in pedestrian areas.

10. Departures from Standards

10.1. I set out the design standards that have been used as the basis for developing

the design to date in Section 3 above. In applying these design documents and

the design standards contained therein to the layout as described in Sections 4,

5 and 6 above, it has not always been possible to achieve the standards in ful/.

The design documents make provision for this and there are acceptable levels

below the full standards which are permissible. These deviations from the ful/

standard are described as Relaxations and Departures.

10.2. In the development of the Scheme layout to date, five Relaxations and eight

Departures have been identified. These are summarised in the fol/owing

paragraphs and are described in detail in Appendix 23 in NSC/2/2.

10.3. Four of the five Relaxations relate to the application of crossfal/ to the road in the

urban section of the road and the fifth to the radius of a crest curve in the vertical

alignment within the urban section of the road. The rationale for three of the

Relaxations relating to crossfal/ is to reduce the works necessary to achieve

satisfactory tie-ins to the existing road infrastructure and for the fourth to reduce

the undulating appearance of the kerb lines through a series of horizontal curves.

The rationale for the Relaxation relating to crest curvature is also to reduce the

works necessary to achieve satisfactory tie-in to the existing road infrastructure.

10.4. Three of the eight Departures relate to permissible combinations of horizontal

curvature and crossfall within the urban section of the road and the rationale for

these Departures is to reduce the works necessary to achieve satisfactory tie-ins

to the existing road infrastructure. One of the Departures relates to the

application of a sag curve at the junction of King Georges Road and Queens

Road and the rationale is again to reduce the works necessary to achieve

satisfactory tie-ins to the existing road infrastructure. Two of the Departures

50


relate to intervisibility at junctions within the urban section of the road and these

are required to avoid demolition of property. The final two Departures are related

to the layout of the roundabout at the A370, one is concerned with stopping sight

distance on the A370 southbound and the other the merging arrangement from

the A370 southbound to the South Bristol Link. Should the recommended

relocation of the speed limit change on the A370 be implemented then the first of

these would fall away and the second was considered a safer layout through the

Road Safety Audit process.

10.5. I am satisfied that aI/ of these proposed Relaxations and Departures are

appropriate and safe in the context of the proposed road.

11. Consideration of Objections

11.1. A number of the objections are related to the highway layout and a response to

these is provided below.

11.2. OBJ/1 to OBJn Whiteknight Cleaning Company, Rushbrooke UK Ltd, Mass

Brickwork, Sutherland Property & Legal Services, Jo Steventon Smith & Mass

Developments

11.2.1 . These objections centre on the loss of existing parking resulting from the

proposed junction between Brookgate and the link road to the South Bristol Link.

11.2.2. With the introduction of the junction, a length of approximately 75 metres of

existing kerbside parking wil/ be lost, albeit on the existing bend and interrupted

by gateways. This was considered as part of the Scheme development and

provision has been made for 11 parking spaces on the link road to the Scheme.

Paral/el and echelon parking are standard highway layouts and are considered to

be safe off-street parking provision.

11.2.3. An area of 17.5 square metres is required from the premises on the corner of

Brookgate in order to properly form the junction of the road link to the Scheme

51


and Brookgate. The swept paths of vehicles has been checked to ensure that

this area of land required is minimised.

11.2.4. If the footpath was constructed on the other side of the road, the road itself would

have to be shifted northwards within the road corridor, resulting in a similar

amount of land take.

11.3. OBJ/9 Osborne Clark obo Paul, Danila and Judy Giannetto

11.3.1. Ground 3 - The access in question serves two land holdings and is whol/y within

the land identified within the CPO. There wil/ be no need for third party access

rights over land to be retained by the Objector.

11.3.2. Ground 4 - Access to the drainage pond for maintenance wil/ be provided directly

from the highway without the need for access over third party land.

11.3.3. Ground 6 - Parcel 04/23 was included as it was understood that the landowner

required direct access to this field.

11.4. OBJ/10 Long Ashton Parish Council

11.4.1. In the case of LA 12/12c/20 it was considered that a reasonably convenient

alternative was available by way of Longmoor Brook Underbridge, aI/owing

separation of pedestrians and vehicular traffic using the Scheme. While the

posted speed wil/ be 40mph, faster speeds may result and it was therefore

considered safer to avoid the potential conflicts.

11.5. OBJ/12 David James & Partners obo Mrs Green

11.5.1. Access to Periwig Cottage is retained to/from the Scheme and drainage of the

property wil/ not be adversely affected as surface water from the Scheme wil/

drain away from the property and will be col/ected by the Scheme drainage.

11.6. OBJ/13 David James & Partners obo J A Wring et al

52


11.6.1. Access to the land in question is to be retained at its current location and the

Scheme development has considered any drainage impacts. There are no

proposals to provide access to land in separate ownership by way of this access.

Discussions were held with the landowner to confirm their access requirements.

11.7. OBJ/14 David James & Partners obo Mr and Mrs Knowlson

11.7.1. Access to Highridge Cottage is provided directly to/from the Scheme on the line

of the existing access to Highridge Green. The Scheme drainage has been

developed such that there wil/ be no adverse impact on the property.

11.8. OBJ/15 David James & Partners obo E Hil/

11.8.1. Access to the retained portion of land to the east of the Scheme wil/ be provided

from the access numbered 4 on Site Plan 3B with the Side Roads Order.

11.9. OBJ/16 David James & Partners obo G R Withers et al

11.9.1. The drainage for the Scheme wil/ be designed such that run-off does not directly

enter the stream. Discussions have been held with the Environment Agency in

this respect.

11.9.2. Traffic flows on this section of the A38 are expected to decrease with the

completion of the Scheme, facilitating right turn movements. The predicted traffic

flows are presented in the evidence of Robert Thompson (NSC/3/1).

11.10. OBJ/17 David James & Partners obo Mrs D Bloyce

11.10.1. I believe access to aI/ fields required has been provided.

11.10.2. It is intended that any large machinery wil/ use the accesses provided to each

field directly from the Scheme. The underpass is only intended to provide

passage for livestock and normal sized vehicles, as discussed with the tenant

farmers and their representatives.

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11.11. OBJ/18 David James & Partners obo J P Boyce, L J Boyce and G Case

11.11.1. AI/ existing accesses tolfrom Whitchurch Lane wil/ be retained to/from the

Scheme and a median strip is to be provided to facilitate right turning of vehicles.

11.12. OBJ/19 David James & Partners obo J P Boyce

11.12.1. AI/ existing accesses to/from Whitchurch Lane wil/ be retained to/from the

Scheme and a median strip is to be provided to facilitate right turning of vehicles.

11.13. OBJ/20 David James & Partners obo G Case and S Case

11.13.1. The Objector has not been specific in terms of access but I believe that suitable

access to the land in question has been provided as part of the Scheme.

11.14. OBJ/28 Ashton Park

11.14.1. The locations of the ponds were set to optimise the drainage provision but are

not considered to unnecessarily isolate parcels of land. The pond adjacent to the

bus link has been relocated between the Planning submission and the Side

Roads Order.

11.15. OBJ/29 Bond Dickinson obo Raymond and John Burnel/

11.15.1. Access arrangements are addressed in the evidence of Paul Wright (NSC/9/1).

11.16. OBJ/30 TL T obo Viridor

11.16.1. The detailing of the surface water attenuation ponds wil/ be discussed with the

landowner during the detailed design to ensure there is no ingress of water into

the landfil/ and to ensure that the existing surface water management system

continues to function in a satisfactory manner.

11.17. OBJ/32 to 35 Phyllis and Raymond James

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11.17.1. Based on discussions held with the landowner, it is understood that reasonably

convenient alternative access has been provided.

11.17.2. Public Right of Way LA 12/15/10 is proposed to be diverted given that where it

currently crosses the line of the Scheme there are likely to be earthworks slopes

and the reasonably convenient alternative avoided the need to cross such

slopes.

11.17.3. The drainage proposals have been developed in accordance with accepted

standards and as such wil/ be engineered as part of the detailed design to avoid

erosion, damage to property and pollution.

11.18. OBJ/40 Steve and Charlotte Johns

11.18.1. It is not proposed to take away the access to 183 Highridge Green but the

existing access wil/ be widened.

11.18.2. Provision has been made in the development of the Scheme to retain access to

the garage by way of a 'yel/ow box' on the Scheme to prevent blocking of the

access.

11.19. OBJ/41 Alan Cox

11.19.1. It is not proposed to take away the access to the garage at 80 Highridge Road,

although with the introduction of the Scheme this access wil/ be left-in and left-

out, with right in possible subject to detailed design.

11.19.2. Provision has been made in the development of the Scheme to retain access to

the garage by way of a 'yellow box' on the Scheme to prevent blocking of the

access.

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11.20. OBJ/43 Mary Walker

11.20.1. A formalised pedestrian crossing will be incorporated as part of the traffic

signalised junction to be constructed as part of the junction between the Scheme

and Highridge Road.

11.20.2. There wil/ also be two non-signalised crossing points with central islands and

dropped kerbs incorporated within the Scheme along the length of the existing

Highridge Green adjacent to the common.

12. Conclusions

12.1 . My preceding evidence has described the rationale for the development of the

Scheme layout and the engineering that lies behind it. I believe that due regard

has been taken of the views and requirements of the various stake holders andthat the Scheme as presented provides an acceptable balance between the

requirements of the road user, other users in terms of pedestrians and cyclists,

and those that have interests adjoining the Scheme.

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in respect of scheme design and engineering · 02/06/2014 · appendix 22 bridge over malago...

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