Highways Agency

• 1. Introduction
• 2. Existing Conditions
• 3. Scheme Proposals
• 4. Engineering Assessment
• 5. Environmental Assessment - 1
• 5. Environmental Assessment - 2
• 5. Environmental Assessment - 3
• 5. Environmental Assessment -4
• 5. Environmental Assessment - 5
• 5. Environmental Assessment - 6
• 5. Environmental Assessment -7
• 5. Environmental Assessment -8
• 5. Environmental Assessment -9
• 5. Environmental Assessment -10
• 5. Environmental Assessment -11
• 5. Environmental Assessment -12
• 5. Environmental Assessment -13
• 5. Environmental Assessment -14
• 5. Environmental Assessment -15
• 5. Environmental Assessment -16
• 5. Environmental Assessment -17
• 5. Environmental Assessment -18
• 5. Environmental Assessment -19
• 6. Traffic and Economic Assessment

4. Engineering Assessment

4.1 Introduction

This chapter presents a detailed engineering assessment of the route options interms of highway alignment, junction layouts, existing and new structures,geotechnics and contaminated land, earthworks, public utilities and compliancewith Standards. Significant engineering difficulties associated with route optionsare also identified.

Reference should be made to Table 4.1 in Appendix A, which provides acomparison of the route options for each of the above engineering parameters.

4.2 Blue Route Option

4.2.1 Mainline Alignment

The alignment details of the Blue Route Option are shown on drawing numbers5021044/DR/HW/202, 203, 205 to 207, 209, 230 to 234 and 240 to 241. As shownon the drawings the proposed Dual 2 Lane All Purpose (D2AP) A14 mainlineleaves the existing A14 corridor to the west of Brampton Hut Junction and headssouth towards the A1 corridor. On approaching the A1 the eastbound carriagewaymoves away from the westbound carriageway and can either rise on embankmentto cross over the A1 or move into cutting to pass beneath the A1. After crossing theA1 the carriageway then returns to follow the existing ground level as the alignmentruns parallel to the A1 and passes beneath the realigned Brampton - GrafhamRoad.

Adjacent to Brampton - Grafham Road, the A1 southbound to A14 eastbound linkdiverges to join the A14 eastbound carriageway as a lane gain turning the A14 intoa Dual 3 Lane All Purpose (D3AP) road east of the A1. Due to traffic volumesbeing higher on the A1 southbound to A14 eastbound slip, the slip road becomesthe mainline and the A14 eastbound merges in from the left.

At the point where it separates from the eastbound carriageway, the westboundcarriageway runs adjacent to the northbound carriageway of the A1, which itcrosses as it turns to move in an easterly direction and rejoin the eastboundcarriageway.

Since the mainline separates in this option and both the eastbound and westboundcarriageways have their own individual alignment the A14 mainline has beendesigned as two separate interchange links at a design speed of 85kph. This hasresulted in lower radii curves being used in the alignment producing a compactlayout in accordance with standards.

From the A1 crossing the A14 mainline runs east and passes to the north of theBuckden North Landfill Site before crossing the River Great Ouse and its floodplainon a multi-span viaduct. The mainline continues in an easterly direction across theEast Coast Mainline railway north of the Wood Green Animal Shelter. It thenpasses to the south of Fenstanton and the Conington Landfill Site prior to rejoiningthe existing A14 mainline to the south of Fen Drayton. In doing so the followinglocal roads require to be bridged:

• Offord Road
• Silver Street
• The A1198
• Moat's Way
• Mere Way
• The B1040
• Hilton Road
• Conington Road

After tying into the existing A14 the proposed mainline comprises online wideningof the existing A14 corridor as far as Lolworth Spring, west of Bar Hill. BetweenTrinity Foot and Lolworth Spring the existing eastbound verge of the A14 containsBT fibre optic cables. As a result of this, together with the need for access to bemaintained to properties on the north side of the A14, the existing road has beenwidened to the south. From Lolworth Spring, the proposed mainline moves offlineto the north of Bar Hill by approximately 110 metres at its maximum point in orderthat a high capacity junction can be constructed to replace the existing junction.After passing Bar Hill the route option requires an extra lane as a result ofincreased traffic volumes accessing the A14 at Bar Hill. It therefore continuesoffline to the west of Girton at the M11 Junction 14 as a Dual 4 Lane All Purpose(D4AP) road.

To the east of Girton the Blue Route Option continues as online widening along theCambridge Northern Bypass to Fen Ditton. From the M11 Junction 14 through theHiston and Milton Junctions to Fen Ditton Junction off-slip the CNB is upgraded toD3AP standard. As a result of traffic volumes a fourth 'auxiliary lane' has beenadded between the merges and diverges between the M11 Junction 14 and MiltonJunction.

With the construction of the improved A14 it is proposed that the existing A14 willbe detrunked between Spittals Junction and Fen Drayton. Included in thisdetrunking works would be the removal of the Huntingdon Railway Viaduct and therealignment of the existing A14 to form an at-grade staggered junction with theB1514, Brampton Road.

4.2.2 Junctions

JUNCTION STRATEGY A

Junction Strategy A has been developed following analysis of the A14 traffic model.It consists of three interchanges, namely Brampton, Fen Drayton and Girton, fourmainline junctions, Bar Hill, Histon, Milton and Fen Ditton and two Local AccessRoad junctions, Trinity Foot and Dry Drayton. These are described below in theorder that they appear along the A14 in a west to east direction together withdetails of the associated Local Access Road (LAR) layout.

Local Access Road

It is proposed that when the A14 improvement scheme is constructed the existingA14 will be maintained for use by local traffic. However, where the proposedmainline utilises the route of the existing A14 a designated Local Access Road(LAR) will be constructed in order to maintain the local road network. The LARlayout has been developed based on traffic flows taken from the A14 traffic modeland influenced by the layout of the Fen Drayton Interchange. It is shown ondrawing numbers 5021044/DR/HW/230 to 232.

Traffic figures indicate that an S2 standard LAR is required between Fen DraytonInterchange and Trinity Foot LAR Junction as well as between Trinity Foot Junctionand Girton Interchange. The layout of Fen Drayton Interchange splits the LAR sothat the eastbound and westbound carriageways run on opposite sides of the A14mainline. This means that the S2 LAR eastbound carriageway runs along theexisting A14 eastbound carriageway to Trinity Foot (to avoid the BT fibre opticcables) and the S2 westbound carriageway runs adjacent to the south of the A14mainline.

To the east of Trinity Foot Junction the LAR continues towards Bar Hill on thesouthern side of the proposed mainline. On approaching Bar Hill the LAR mergeswith the existing A14 westbound carriageway at the point where the proposed A14mainline moves offline and continues along the existing westbound carriageway tothe M11 Junction 14 via Bar Hill and Dry Drayton Junctions. At the M11 Junction 14it passes over the A14 westbound Link, under the A14 mainline and over both theA428 Links before tying into Huntingdon Road.

A1 Brampton Interchange

The proposed interchange arrangement, shown on drawing number5021044/DR/HW/202, involves a restricted movement option that links the existingA1 Southbound carriageway with the proposed A14 Eastbound carriageway andthe proposed A14 Westbound carriageway with the existing A1 Northbound andSouthbound carriageways. On joining the proposed A14, the A1 Southbound toA14 Eastbound Link does not merge into the mainline, instead it becomes a lanegain, converting the A14 from a D2AP carriageway to a D3AP carriageway east ofthe A1. Similarly, the A14 Westbound carriageway experiences a lane drop wherethe A14 Westbound to A1 Northbound/Southbound Link leaves the mainline,reducing the westbound carriageway of the A14 from a D3AP to a D2AP.

The proposed A14 Westbound to A1 Northbound Link crosses over the existing A1mainline and passes under the proposed A14 before tying into the A1 Northboundcarriageway just north of the Brampton-Grafham Road structure. The result ofwhich is the need for a new structure to maintain the local road over the A1 and thedemolition of a cottage with frontage onto the A1.

Also requiring demolition is a filling station that is affected by the realignment ofBuckden Road. In order to lift the local road over the mainline it must be takenoffline as shown on drawing number 5021044/DR/HW/202.

The location at which the proposed A14 crosses the existing A1 means thatBrampton Interchange is situated in close proximity to the existing A1/A14 Junctionat Brampton Hut. Therefore to accommodate any potential weaving issues on thestretch of the A1 between these two junctions an additional lane has been added tothe existing A1 between Brampton Hut and Buckden on both the Northbound andSouthbound carriageways.

Fen Drayton Interchange

The proposed interchange arrangement is shown on drawing number5021044/DR/HW/209 and involves a two-level, restricted movement interchangethat links the proposed A14 mainline with the local road network just to the west ofwhere the proposed A14 ties into the existing A14. The interchange allows thefollowing traffic movements:

• A14 Eastbound to LAR Eastbound
• LAR Eastbound to A14 Eastbound
• A14 Westbound to LAR Westbound
• LAR Westbound to A14 Westbound

All other movements, for example A14 Eastbound to LAR Westbound, can bemade by using the Trinity Foot LAR Junction which is situated approximately 1 kmeast of the Fen Drayton Interchange.

The location at which it is proposed to site the Fen Drayton Interchange sees theproposed A14 mainline on an embankment of between 2 - 3 metres in order thatthe road sits above the maximum flood level of a floodplain in the area. The impacton the interchange involves the vertical alignment having to be designed so that itcrosses over the A14. This produces a design that requires large amounts of fillmaterial to construct embankments that reach 10 metres in places.

Trinity Foot LAR Junction

Trinity Foot Junction is comprised of two roundabouts, one either side of theproposed A14, connected by a link that crosses mainline. The northern roundaboutis located to the west of Buckingway Business Park, north of the existing TrinityFoot Public House (Refer to drawing number 5021044/DR/HW/230). This is linkedto the existing Boxworth Road roundabout on the south of the A14 mainline by aD2AP standard road. The northern roundabout consists of four arms, one of whichis the link to the southern roundabout. The other three consist of the LAR from thewest, the realigned Buckingway Road from the north and another LAR to the eastaccessing properties on the north side of the A14.

The Blue and Orange Route Options have the D2AP westbound LAR carriagewaycoming off the dumbbell link to the south of the mainline. There is no designatedright turn lane on the link to provide access to the westbound carriageway for trafficcoming from the north and over the mainline, as this would involve widening thejunction structure considerably. Instead traffic will continue on the junction link fromthe north and use the southern dumbbell roundabout to double back to access thewestbound carriageway of the LAR.

Bar Hill Junction

The proposed junction, shown on drawing number 5021044/DR/HW/231, involvesa two bridge roundabout layout situated over the offline section of the A14 to thenorth of the existing junction. This allows the proposed LAR to run to the south ofthe mainline along the existing A14 and prevents local traffic from conflicting withtraffic in Bar Hill.

This option provides access to the B1050 Longstanton Road to the north, and to adual carriageway link to a new roundabout serving the local link road to the south.A short length of dual carriageway is also provided between this local linkroundabout and the existing Bar Hill roundabout, which would be retained in itspresent form. These sections of dual carriageway are necessary to cater foranticipated growth in traffic volumes arising from the proposed development atNorthstowe.

As a result of this development the major traffic flow through the junction will bebetween Cambridge and Northstowe and vice versa. Therefore in order to relievethe junction of the predicted high traffic flows generated by the development adesignated link and designated lane between Hatton's Road and the A14 mainlineand junction slip roads has been included within the junction layout.

The single lane link road to carry traffic between the A14 westbound carriagewayand Hatton's Road, diverges from the proposed A14 mainline westboundcarriageway and crosses over the link road between the junction roundabout andthe LAR roundabout. It then proceeds on a curve across the junction's west facingslips and the D3AP mainline before tying into Hatton's Road to the north.

Traffic flowing in the reverse direction will be segregated from Bar Hill Junction by adesignated lane between the realigned Hatton's Road southbound carriageway andthe junction's eastbound on slip.

Dry Drayton LAR Junction

The proposed A14 mainline alignment completely removes the existing junction atDry Drayton (Refer to drawing number 5021044/DR/HW/232). The displacement ofthe A14 mainline to the north of its existing alignment necessitates a new DryDrayton Junction.

The junction consists of a four armed roundabout to the south of the A14 allowingtraffic to access Oakington Road and Dry Drayton Road from the west to eastrunning LAR and vice versa. Access from the A14 mainline to Dry Drayton in thesouth and Oakington in the north will be available via the LAR connection at BarHill.

M11 Junction 14

M11 Junction 14 is a strategic interchange that links three major routes with freeflow movement. It routes traffic from the M11 motorway and the CambridgeNorthern Bypass onto the A14. The existing interchange incorporates a number offeatures that are undesirable for the level of strategic traffic carried.

The following geometric and operational deficiencies are built into the currentlayout:

• The A14(E) to A14(W) traffic passes through a tight uphill loop slowing traffic down and creating congestion, particularly in the evening peak.
• Further turbulence occurs when A14(E) to A14(W) traffic weaves with M11(S) to A14(E) traffic along a stretch of road which is too short to allow safe weaving manoeuvres.
• Further weaving occurs to the west where the Midlands bound strategic traffic weaves with local traffic leaving Cambridge on the A1307. This is compounded by the proximity of the diverge to Madingley and subsequent merge with the M11 results in driver confusion, slowing the flow of traffic.
• In the morning peak hour slow moving traffic on the A1307 into Cambridge often queues back to the diverge for the A14 eastbound link. This queuing of local traffic obstructs the free flow of strategic A14 traffic.
• The substandard horizontal alignment of the interchange link between A14(E) and M11 provides substandard visibility.
• Strategic eastbound traffic merging flow is greater than the A428 eastbound traffic. This wrong sided merge gives rise to turbulence with short headways and sudden braking and will continue to worsen as the A14 traffic continues to grow.
• The objective of the A14 Improvement Scheme is to eliminate as many of these deficiencies as possible, most of which arise from the interaction of strategic traffic with local users.

The proposed junction, shown on drawing number 5021044/DR/HW/232, uses theexisting links and slip roads as much as possible and retains the existing bridges.This provides a compact design at minimal cost and environmental impact.

The junction design provides an improved strategic traffic movement for the A14eastbound to A14 westbound, which is currently achieved by a tight radius loop.This loop is removed and replaced with an interchange link, designed to a higherdesign speed than the existing. By removing this existing loop the weavingproblems created between the existing diverge, from the M11 northbound to theA14 eastbound are eliminated.

The design of the A14 eastbound to A14 westbound interchange link requires therealignment of the A428 to A14 eastbound link. The link merges the major A14eastbound traffic on the slow side thus eliminating the problem of turbulencediscussed above.

The A14 westbound to A14 eastbound interchange link is aligned along the existinglink until just after the u-turn for the crematorium. After the u-turn (removed in thisdesign) it moves slightly to the north in a greenfield site where the link crosses theA428 to A14E and merges with it on the right hand side.

No change is envisaged to the A14 eastbound to M11 slip road.

Another important aspect this option achieves is the segregation of long distancestrategic traffic from the local traffic. The current A1307 LAR, which is dualcarriageway, directly links into the A14 traffic. These links have been removed inthis design and replaced with a single carriageway road that utilises the currentLAR westbound alignment. The new alignment utilises the existing HuntingdonRoad Bridge and the LAR is segregated from the A14 mainline and aligned to thesouth.

Histon Junction

The existing two overbridges and County Road gyratory above the A14 at Histonare not directly affected by the Cambridge Northern Bypass improvements.

Milton Junction

The existing two overbridges and County Road gyratory above the A14 at Miltonare not directly affected by the Cambridge Northern Bypass improvements.

Fen Ditton Junction

The proposal retains the existing half diamond junction with the slip roads beingredesigned to accommodate predicted traffic flows.

JUNCTION STRATEGY B (LIMITED JUNCTION OPTION)

Junction Strategy B, known as the Limited Junction Option (LJO), has beendeveloped in order to minimise the number of locations where local traffic canaccess the A14. This allows the A14 to primarily become a strategic traffic route.

As with Junction Strategy A, Strategy B consists of three interchanges, namelyBrampton, Fen Drayton and Girton. However, there are only three mainlinejunctions, located at Histon, Milton and Fen Ditton and three Local Access Roadjunctions, Trinity Foot, Bar Hill and Dry Drayton. The only junctions, however, thatdiffer to those described for Junction Strategy A are Bar Hill Junction, Dry DraytonJunction and Girton Interchange. These are described below in the order that theyappear along the A14 in a west to east direction together with details of theassociated Local Access Road (LAR) layout.

Local Access Road

As with Junction Strategy A, the LAR layout has been developed through theanalysis of the A14 traffic model and influenced by the layout of the Fen DraytonInterchange. This LAR is shown on drawing numbers 5021044/DR/HW/230 and240 to 241.

Between Fen Drayton Interchange and Bar Hill the LAR has the same layout asdescribed in Section 4.2.2 for Junction Strategy A. At Bar Hill Junction there is noaccess to or from the A14 therefore the LAR returns to a D2AP at this point toaccommodate the high volumes of traffic that will use the LAR between Cambridgeand Northstowe. To reflect this on the A14 the mainline remains as a D3AP throughBar Hill to M11 Junction 14.

At Bar Hill the LAR splits into two separate carriageways, with the eastboundcarriageway running adjacent to the A14 mainline and the westbound carriagewaycontinuing along the existing A14 westbound carriageway. The LAR continuesunder this arrangement until the two carriageways join back together before tyinginto Huntingdon Road.

Bar Hill LAR Junction

The Bar Hill Limited Junction Option, as shown on drawing number5021044/DR/HW/240, consists of a dumbbell roundabout layout linking Bar Hill andthe proposed Northstowe development with the LAR network. There is no accessto or from the proposed A14 mainline. The S2 LAR that runs to the west of Bar Hillties into the southern dumbbell roundabout, which is linked to both the existing BarHill roundabout to the south and the second dumbbell roundabout to the north by aD2AP standard link road. As well as this link the northern roundabout also has therealigned S2 Hatton's Road and eastbound carriageway of the Bar Hill to Girtonsection of the LAR tying into it.

As with the Junction Strategy A, the major traffic flow at this junction will bebetween Cambridge and the proposed Northstowe development except that trafficwill be on the LAR rather than the mainline. Therefore to avoid feeding these flowsthrough the LAR junction two designated links have been included in the junctionlayout. The westbound link has the same geometry and is very similar in its route tothat described in the Junction Strategy A section. The westbound carriageway ofthe D2AP LAR splits on the approach to Bar Hill with the LAR continuing through tothe southern dumbbell roundabout and the designated link crossing over thedumbbell link and the A14 mainline before tying into Hatton's Road. Under theproposals of the Northstowe development Hatton's Road is proposed to beupgraded to D2AP standard, therefore the link will merge with Hatton's Road as alane gain to coincide with these proposals.

Similarly, to divert traffic travelling from Northstowe to Cambridge away from thejunction itself a designated left turn link has been provided between Hatton's Roadand the eastbound carriageway of the LAR. To tie-in with the proposals for Hatton'sRoad this link diverges from Hatton's Road as a lane drop leaving an S2carriageway running into the northern dumbbell. The link then acts as a lane gainon the eastbound carriageway of the LAR where it merges with the LAR as itleaves the northern dumbbell.

Dry Drayton LAR Junction

As with the junction option for Junction Strategy A the Dry Drayton LJO is an LARjunction. As drawing number 5021044/DR/HW/241 shows the junction spans theD3AP mainline and the split D2AP LAR. Connection between Oakington Road/DryDrayton Road and the LAR is provided via a dumbbell layout, which is linked to leftin/left out junctions with the LAR.

M11 Junction 14

The layout of M11 Junction 14 associated with the LJO (Refer to drawing no.5021044/DR/HW/241) is intended to perform the same function as the option forthe previous junction strategy in that it utilises the existing corridors of theinterchange links and slip roads as much as possible and retains the existingbridges.

However the LJO layout provides linkage between the D2AP LAR/HuntingdonRoad and the trunk road/motorway network whereas the Junction Strategy A runsthe S2 LAR directly through the junction into A1307 Huntingdon Road with noconnection. The provision of LAR links to the original junction option layout createsan additional six link roads within the junction. The most significant of the twelvemerging and diverging movements introduced by these links are those interfacingwith the trunk road/motorway network, as listed below:

• A diverge in the A14 westbound interchange link approximately 700 metres in advance of the A14 westbound merge with M11 westbound traffic.
• A merge into the A14 eastbound interchange link approximately 500 metres in advance of its next merge with the A428 eastbound carriageway.
• A merge into the M11 southbound mid-way between its A14 eastbound diverge and the A14/A428 southbound merge.

4.2.3 Structures

EXISTING STRUCTURES

Existing structures along the scheme have been discussed in Section 2.5. Tables4.2 and 4.3 of Appendix B list those structures affected by the Blue Route Optionand makes recommendations as to their treatment under this project.

NEW STRUCTURES

In carrying out the preliminary design of new structures, the identified structures,where appropriate, have been grouped by structural type. For each group, aconceptual design has been worked up, based on similar structures that have beenfound to be economic on other recent schemes.

The groups are shown on the following drawings:

• 5021044/DR/BR/002 - Bridges Group 1, two span overbridge, open abutments
• 5021044/DR/BR/003 - Bridges Group 2, two span overbridge, closed abutments
• 5021044/DR/BR/018 - Bridges Group 3, bridleway/footbridge, two span overbridge
• 5021044/DR/BR/019 - Bridges Group 4, three span overbridge, closed abutments
• 5021044/DR/BR/006 - Bridges Group 5, single span underbridge
• 5021044/DR/BR/007 - Bridges Group 6, two span underbridge, open abutments
• 5021044/DR/BR/020 - Bridges Group 7, four span overbridge, open abutments
• 5021044/DR/BR/010 - Bridges Group 8, Girton Grange Accommodation Bridge.

Where space is available, open abutments (bankseats) have been shown, sincethey are generally considered to be more aesthetically attractive. Where space isrestricted, eg at junctions, closed (full height) abutments have been shown.

Steel composite construction has been assumed, since this has been found to bemore cost effective than concrete on recent schemes. However, concretesolutions, particularly precast concrete beams, will be equally technicallyacceptable.

It should be noted that the drawings show concepts and indicative details; nocalculations have been done to determine member sizes.

The major structure on this route option is the River Great Ouse Viaduct, whichcrosses the flood plain of the River Great Ouse. Details of this structure are shownon drawing numbers 5021044/DR/BR/008 and 009.

Tables 4.4 to 4.7 in Appendix C detail the number of new structures required for theBlue Route Option.

4.2.4 Relaxations and Departures From Standards

As a result of various constraints along the scheme corridor it has been necessarywhen designing the scheme to drop below desirable minimum standards in certainlocations, as permitted by the Highway Agency's Design Manual for Roads andBridges (DMRB).

The Blue Route Option mainline has been designed to standard without the need toincorporate any relaxations or Departures from Standards. However, a number ofsideroads and junctions along the route have been designed with substandardgeometry in order to minimise the impact on the surrounding area. In some of thesecases, where the geometry has had to be significantly reduced in standard, adeparture from standards has been applied for to the Highways Agency or localhighway authority for their approval. Table 4.8 in Appendix D details the Departuresfrom Standards for the Blue Route Option and provides a statement justifying theirinclusion in the scheme.

4.2.5 Earthworks

The alignment of the Blue Route Option begins by following the existing groundlevel on its approach to the A1 corridor before extensive earthworks in the form ofembankments are proposed as part of the A1 Brampton Interchange. Where thereare two A14 eastbound options for crossing the A1, it is the option that passesbeneath the A1 in cutting that is preferable in terms of earthworks, due to therebeing a shortfall of generated material along the scheme. However, it should benoted that other aspects of the design, for instance drainage and construction ofthe bridge under the A1 make this option less favourable.

From the A1 Brampton Interchange to the A1198 the main earthworks required arethe approach embankments to the River Great Ouse Crossing and the cuttingthrough the ridge to the south of Godmanchester. The Blue Route Option hasembankment heights of up to 13 metres at the River Great Ouse and cutting depthsof approximately 7-8 metres where the route intersects the A1198, masking it fromthe town of Godmanchester.

From the A1198 to the point where the route joins the existing A14 at Fen Drayton,the proposed route option generally follows the local topography requiring onlyminor cuttings and low embankments. The vertical alignments indicate that thedepth of these cuttings does not exceed 6 metres.

The low embankments referred to above have been deliberately designed into thescheme to ensure that the route runs above the flood levels of the localisedfloodplains along the A14 corridor. Fen Drayton Interchange is located on afloodplain and therefore requires embankments of up to 9 metres in order to lift thelink roads over the raised mainline.

It is the junctions and side roads within the Blue Route Option that constitute themajority of the fill required. This is because all the side roads cross above the A14mainline. For the more major side roads large sweeping alignments have beendesigned that have resulted in long lengths of embankment.

To the east of Fen Drayton Interchange the mainline mainly follows the route of theexisting A14 to Fen Ditton with the existing carriageway and earthworks beingwidened. The existing carriageway tends to follow the existing ground level with afew minor embankments and small cuttings in isolated locations. Therefore, theproposed mainline will not require any major online embankments until reachingthe CNB where widening of the existing 8 metre high embankments are required.Major earthworks are required for the numerous associated junctions, in particularthe designated Northstowe Links at Bar Hill and the M11 Junction 14 options. Alljunctions cross over the mainline and are therefore on embankment. The lack ofsite won material at this end of the scheme, as a result of there being few cuttings,means that fill material will have to be imported for the construction of the junctionembankments.

The only significant cutting in the eastern end of the scheme is where the A428eastbound carriageway is realigned to tie into the Cambridge Northern Bypass.Approximately 750 metres of the link is situated in a cutting of some 4 metresdepth.

Drawing numbers 5021044/DR/HW/202, 203, 205 to 207, 209, 230 to 234 and 240to 241 provide details of the heights of the earthworks required along the schemeand Table 4.1 in Appendix A schedules the volume of cut and fill for all the schemeroute options. Drawing numbers 5021044/DR/HW/301 & 302 show typical crosssectionstaken through the various route options and provide an indication of thescale of the major earthworks.

4.2.6 Contaminated Land

In addition to the landfill sites at Buckden, Conington and Milton, as discussed inSection 2.4.4, there are also several potential contaminated sites associated withboth former and existing petrol stations, fuel and goods distribution depots,scrapyards and vehicle repair garages.

South of Brampton village, to the north of the proposed Blue Route Optionalignment and the Buckden North landfill site a former petrol station is present.Although there is no visual evidence of contamination on the surface of the sitethere is a possibility that the associated underground fuel storage tanks may havehistorically leaked or discharged fuels into the underlying ground and groundwater.Therefore, as the realignment of Buckden Road impacts on this filling station thereis a possibility that the ground and groundwater beneath the route may be affectedby contaminant migration.

In the vicinity of the proposed Trinity Foot Junction a number of potentialcontaminated sites have been identified, including electroplating and metal finishingworkshops, existing and former petrol stations. The potential environmental issuesof these sites may impact on the proposed junction works at Trinity Foot and furtherinvestigation would be required at Trinity Foot prior to construction to verify if anycontamination is present which may impact upon the construction works or thescheme in the long-term.

Also within the area is an industrial estate south of Bar Hill, which contains anumber of industrial processes which may have led to contamination entering theunderlying geology and groundwater regimes. Activities include an operationalpetrol filling station, transformer manufacture, printers and glass fibre manufacture.

The industrial estate lies to the south of the existing A14 and with off-line wideningto the north being the favoured option it is unlikely that any ground contaminationwill be encountered along this northern route by the proposed road construction.

To the east of the scheme there are areas to the east and south of Milton Junctionassociated with activities such as vehicle repair, scientific apparatus andinstrumentation manufacture, pharmaceutical manufacturers and distributors. Tothe north and east of Milton junction there are enamelling and sheet metal works,garage services, printers, cleaning services, hydraulic equipment servicing andscientific apparatus and instrumentation manufacture.

None of the above sites lie beneath the proposed construction route of the existingA14, and contaminant migration is likely to be minimal due to the underlyinggeology consisting predominantly of cohesive materials or clays. However, an oldrailway yard and part of the existing sewage treatment works historically underliethe existing A14 / Cambridge Northern Bypass prior to its construction. Thereforefurther widening of the A14 / Cambridge Northern Bypass may encounter potentialcontamination associated with these former uses.

4.2.7 Public Utilities

As the Blue Route Option travels from west to east the first major conflict withStatutory Undertakers' (SU) apparatus is an oil pipeline that runs in a north to southdirection parallel with the A1. Due to the angle at which the route option crossesthe pipeline it is likely that a diversion will be required rather than just theimplementation of protection measures.

East of the oil pipeline there are minor conflicts with SU apparatus (mainly watermains) where the local road network requires realigning in order to cross themainline. The next major impact occurs with BT fibre optic cables, which run in theexisting A14 eastbound verge between Fenstanton and Bar Hill. The proposed A14Eastbound to LAR Eastbound Link of the Fen Drayton Interchange crosses thisapparatus in two places as does the proposed A14 mainline as it moves offline atLolworth Spring to the north of Bar Hill.

In the same location but in the existing A14 westbound verge are 300mm diameterpotable water mains. As a result of widening this section of the existing A14 to thesouth these mains require diverting. A number of 6" and 8" gas mains are alsoaffected where they cross the mainline at Trinity Foot and Bar Hill. Foul seweragepipes that run from the Huttons Drove Sewage Treatment Works, between TrinityFoot and Bar Hill, across the existing A14 require rerouting as a result of the BlueRoute Option.

At the eastern end of the scheme the CNB was originally constructed largelythrough a green field site where disturbance to utilities was minimal. ExistingStatutory Undertakers' plant tends to cross the CNB radially into Cambridge andcrosses above the A14 in bridge decks at Histon and Milton junctions. Thesebridges, and hence the plant, are not directly affected by the Blue Route Optionproposals.

However one main, a 200mm diameter gas main running for 1,600 metreslongitudinally in the north verge of the embankment at Girton, is directly affected.Furthermore a 180mm polyethylene gas main and a cluster of minor servicescrossing in the Girton Road overbridge deck are affected as this bridge deck isrequired to be replaced.

The impact in terms of cost that each route option has on the StatutoryUndertakers' apparatus is listed in Table 4.1 in Appendix A.

4.3 Purple Route Option

4.3.1 Mainline Alignment

As can be seen on drawing numbers 5021044/DR/HW/210 to 218, and 230 to 234the alignment of the Purple Route Option matches that of the Blue Route Option upto a point between the A1198 and Moat's Way. From here it runs in a north easterlydirection before tying into the existing A14 to the west of Gore Tree Farm where itcontinues to run online through Fenstanton to Fen Drayton and on to Fen Ditton.

The online section of the route option consists of asymmetrical widening to thenorth in order to avoid properties on the fringes of the southern side of the existingA14 between Gore Tree Farm and Galley Hill. By widening to the north a Site ofSpecific Scientific Interest located to the east of Gore Tree Farm is also avoided asare BT fibre optic cables situated in the existing A14 southern verge.

Between Galley Hill Junction and Fen Drayton the existing A14 is widenedasymmetrically to the south, enabling the existing local road network to be utilisedfor local traffic between Galley Hill and Fenstanton whilst at the same time avoidingthe conservation area within Fenstanton. However, it does result in the loss of fourhouses, disused farm outbuildings and a BT Feeder Station along the route. It alsorequires some substantial diversion works of Statutory Undertakers' apparatus(refer to Section 4.3.7).

In order to separate the local traffic from the strategic traffic on the proposed A14, aSingle 2 Way (S2) Local Access Road (LAR) has been provided. The LAR utilisesthe existing section of the A14 between Huntingdon and Gore Tree Farm, which ismade redundant by taking the proposed A14 offline. At Galley Hill the LAR is linkedinto the proposed Galley Hill Junction before proceeding on the route of the existingaccess road to the west of Fenstanton. It continues adjacent to the mainline alongthe boundary of the Fenstanton conservation area where it merges withFenstanton's original bypass. This avoids directing local through traffic along thevillage's narrow high street. From Fenstanton the LAR runs adjacent to thewidened A14 on the eastbound carriageway of the existing A14.

With the construction of the improved A14 it is proposed that the existing A14 willbe detrunked between Spittals Junction and Hemingford Grey. Included in thisdetrunking works would be the removal of the Huntingdon Railway Viaduct and therealignment of the existing A14 to form an at-grade staggered junction with theB1514, Brampton Road.

4.3.2 Junctions

Following the analysis of the A14 traffic model only one junction strategy wasdeemed viable for the Purple Route Option. The strategy consists of twointerchanges, namely Brampton and M1 Junction 14, five mainline junctions, GalleyHill, Bar Hill, Histon, Milton and Fen Ditton and two Local Access Road junctions,Trinity Foot and Dry Drayton.

With the exception of Galley Hill Junction, the junctions listed above are the sameas those described for the Blue Route Option Junction Strategy A in Section 4.2.2.Galley Hill Junction is described below.

JUNCTION LAYOUT

Galley Hill Junction

The proposed junction arrangement situated in the same area as the existingGalley Hill Junction and shown on drawing number 5021044/DR/HW/217,comprises a two-bridge, grade separated, large radius roundabout allowing allmovements to and from the A14 mainline. The roundabout contains nine arms, fourof which are the westbound and eastbound on and off slip roads. The remainingarms connect into the local road network including the B1096 St Ives Road to thenorth and the B1040 to the south. There is access to the LAR located on thesection of existing A14 that has been made redundant by taking the mainlineoffline, as well to the recently levelled development area to the south east of thejunction.

The location of the proposed junction is very confined, with property and landconstraints affecting the layout of the junction. As a consequence retainingmeasures will be required in order that the junction slip roads can run in closeproximity to the mainline and allow a compact layout. A retaining measure will alsobe required to avoid a mobile phone mast and station. To the north-west of thejunction the LAR impacts on the nearby Galley Hill farm, where a farm house andsome disused outbuildings would require demolition.

4.3.3 Structures

EXISTING STRUCTURES

Existing structures along the scheme have been discussed in Section 2.5. Tables4.2 and 4.3 of Appendix B list those structures affected by the Purple Route Optionand makes recommendations as to their treatment under this project.

NEW STRUCTURES

The major structure on the Purple Route Option is the River Great Ouse Viaduct,which crosses the floodplain of the River Great Ouse as shown on drawing number5021044/DR/BR/008. For further details of new structures refer to Section 4.2.3.

4.3.4 Relaxations and Departures From Standards

The Purple Route Option mainline runs primarily on the line of the existing A14,therefore a series of relaxations from standard have been incorporated into thedesign in order to minimise the impact on nearby properties.

A number of sideroads and junctions along the route have been designed withsubstandard geometry to affect as little of the surrounding area as possible. Insome of these cases, where the geometry has had to be significantly reduced instandard, a departure from standards has been applied for to the Highways Agencyor local highway authority for their approval. Table 4.8 in Appendix D details theDepartures from Standards for the Purple Route Option and provides a statementjustifying their inclusion in the scheme.

4.3.5 Earthworks

As the Purple Route Option follows the existing A14 alignment there is very littleneed for any major earthworks on the online section as it tends to follow the localtopography. The exception to this is in isolated areas where the road climbs onembankment to rise above localised floodplains.

The commonality between this route option and the Blue Route Option means thatthere is a 9 metre deep cutting to the east of the A1198 between chainages 10000and 11150. This is to mask the route from the town of Godmanchester and toenable fill material to be generated.

It is the junctions and side roads within the Purple Route Option that require themajority of the fill material. This is because all the side roads cross above the A14mainline. For the more major side roads large sweeping alignments have beendesigned that have resulted in long lengths of embankment. However, the PurpleRoute Option has the lowest earthworks imbalance of the route options as a resultof having fewer side road crossings.

4.3.6 Contaminated Land

For details of contaminated land refer to Section 4.2.6.

4.3.7 Public Utilities

The Purple Route Option affects the same Statutory Undertakers' apparatus as theBlue Route Option with the exception of the gas mains to the south of Fenstanton.By widening the existing A14 to the south when coming online, fibre optic cables inthe existing A14 westbound verge between Galley Hill and Fenstanton aredisrupted and require diverting. A BT feeder station requires demolishing to thesouth of Fenstanton as a result of the widening, which also impacts onapproximately 2.5km of water main.

The impact in terms of cost that each route option has on the StatutoryUndertakers' apparatus is listed in Table 4.1 in Appendix A.

4.4 Orange Route Option

4.4.1 Mainline Alignment

The alignment details of the Orange Route Option are shown on drawing numbers5021044/DR/HW/222, 224 to 226, 228, 230 to 234 and 240 to 241. As shown onthe drawings the proposed Dual 2 Lane All Purpose (D2AP) A14 mainline leavesthe existing A14 corridor to the west of Brampton Hut Junction and heads south,adjacent to the west of the A1 before crossing it further south than the Blue andPurple Route Options.

On leaving the A1 A1 Brampton Interchange the Orange Route Option passes tothe south of the Buckden South Landfill Site before crossing the River Great Ouseand its floodplain and the East Coast Mainline railway on a multi-span viaduct. TheD3AP mainline continues in an easterly direction passing to the south of the WoodGreen Animal Shelter. In doing so it crosses a number of local roads, which arelisted below:

• Offord Road
• Silver Street
• The A1198
• Mere Way
• The B1040
• Hilton Road
• Conington Road

This route option then passes approximately 1.5km to the north of the village ofHilton before continuing eastwards to the site of the Fen Drayton Interchange.From this point it continues to Fen Ditton along the same alignment as the BlueRoute Option.

With the construction of the improved A14 it is proposed that the existing A14 willbe detrunked between Spittals Junction and Fen Drayton. Included in thisdetrunking works would be the removal of the Huntingdon Railway Viaduct and therealignment of the existing A14 to form an at-grade staggered junction with theB1514, Brampton Road.

4.4.2 Junctions

The Orange Route Option has two junction strategies, both of which are almostidentical to those described for the Blue Route Option. The difference between thetwo strategies is the location of the A1 Brampton Interchange, which is describedbelow for the Orange Route Option. For details of the other junctions refer toSection 4.2.2.

A1 BRAMPTON INTERCHANGE

The layout of Brampton Interchange for the Orange Route Option is similar to thatof the Blue Route Option in that the same restricted movements are provided for.The existing A1 Southbound carriageway is linked with the proposed A14Eastbound carriageway and the proposed A14 Westbound carriageway has links tothe existing A1 Northbound and Southbound carriageways. The proposed A14Westbound to A1 Northbound Link crosses over the existing A1 mainline andpasses under the proposed A14 before tying into the A1 Northbound carriagewayat the existing Brampton-Grafham Road structure. By taking the A14 mainlinefurther south and locating the interchange further south, this link is tied into theexisting A1 Northbound carriageway and can be accommodated by the existingstructure.

The vertical alignment of the A14 Westbound to A1 Northbound Link requires substandardvertical geometry in order for it to pass under Brampton Road and overthe A1 before passing beneath the proposed A14. This is discussed in more detailin Section 4.4.4.

As with the Blue and Purple Route Options the location at which the proposed A14crosses the existing A1 means that Brampton Interchange is situated in closeproximity to the existing A1/A14 Junction at Brampton Hut. Therefore, an additionallane has been added to the existing A1 between Brampton Hut and Buckden onboth the Northbound and Southbound carriageways to accommodate weaving.

4.4.3 Structures

EXISTING STRUCTURES

Existing structures along the scheme have been discussed in Section 2.5. Tables4.2 and 4.3 of Appendix B list those structures affected by the Blue Route Optionand make recommendations as to their treatment under this project.

NEW STRUCTURES

The major structure on the Orange Route Option is the River Great Ouse Viaduct,which crosses both the floodplain of the River Great Ouse and the adjacent runningEast Coast Mainline (ECML) railway as shown on drawing number5021044/DR/BR/004. For further details of new structures refer to Section 4.2.3.

4.4.4 Relaxations and Departures From Standards

As with the Blue Route Option the Orange Route Option mainline has beendesigned without the need for any relaxations or Departures from Standards.Relaxations were however required in the design of Fen Drayton Interchange aswell as in the realignment of some of the existing roads in order that they could betaken across the proposed A14 mainline.

The vertical alignment of the A14 Westbound to A1 Northbound Link has a numberof constraints along its alignment that were required to be taken into account whendesigning the link. In order to avoid these constraints the geometry has had to besignificantly reduced in standard and a departure from standards has been appliedfor to the Highways Agency for their approval. Table 4.10 in Appendix D lists anddetails the departures from standards for the Orange Route Option as well asproviding a statement justifying their inclusion in the scheme.

4.4.5 Earthworks

The alignment of the Orange Route Option begins by following the existing groundlevel on its approach to the A1 corridor before extensive earthworks in the form ofembankments are proposed as part of the A1 Brampton Interchange.

From the A1 Brampton Interchange to Fen Drayton the main earthworks requiredare the approach embankments to the River Great Ouse/ECML Crossing, whichreach heights of approximately 13 metres, and the cutting through the ridge to thesouth of Wood Green Animal Shelter, which has a maximum depth of 8 metres.The Orange Route Option also has a pronounced cutting between Offord Road andSilver Street, approximately 2 km in length and up to 11 metres in depth.

From Silver Street to the point where the route joins the existing A14 at FenDrayton, the proposed route option generally follows the local topography requiringonly minor cuttings and low embankments. The low embankments referred toabove have been deliberately designed into the scheme to ensure that the routeruns above the flood levels of the localised floodplains along the A14 corridor. FenDrayton Interchange is located on a floodplain and therefore requiresembankments of up to 9 metres in order to lift the link roads over the raisedmainline.

From Fen Drayton to Fen Ditton the Orange Route Option has the same alignmentas the Blue Route Option and hence the same earthworks. These are described inSection 4.2.5.

As with the Blue and Purple Route Options there is an overall shortfall of materialgenerated along the route as a result of the number of sideroads that cross themainline on embankment. However, the greater number of cuttings along theOrange Route does mean that it has a lower imbalance of material compared withthe Blue Route Option. This is shown in Table 4.1 of Appendix A.

4.4.6 Public Utilities

The public utilities affected by the Orange Route Option are very similar to thosedescribed for the Blue Route Option. The first main conflict occurs with an oilpipeline that runs in a north to south direction parallel with the A1. The angle atwhich the route option crosses the pipeline requires a diversion of the pipelinerather than just the implementation of protection measures.

Minor conflicts with SU apparatus (mainly water mains) on the local road networkare present where the sideroad is realigned to cross the mainline. The next majorimpact occurs where the mainline ties back into the existing A14 corridor havingrun offline from Brampton Hut. Conflicts with BT fibre optic cables, water mains andgas mains occur where the proposed route impacts on the existing verges.Reference should be made to Section 4.2.7 regarding these conflicts as they areidentical to those described for the Blue Route Option.

The impact in terms of cost that each route option has on Statutory Undertakers'apparatus is listed in Table 4.1 in Appendix A.