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

3. Scheme Proposals

3.1 Description of Scheme Options

As discussed below a wide range of scheme options have been identified anddeveloped prior to the technical appraisal stage of this commission. From these,three principal route options (plus local alternatives) and four junction strategieswere taken forward for full technical, environmental and economic appraisal.

As mentioned in Section 1.6 this Scheme Assessment Report aims to summarisethe technical appraisal process. However, in doing so it will only concentrate onthose route options that the technical appraisal has shown as being most likely tomeet the objectives and limitations of the scheme brief. These options aredescribed below.

3.1.1 Do-Minimum Option

A Do-Minimum scenario has been developed to represent the most realistic view oftransport conditions without improvements to the A14. This allows comparisons tobe drawn in terms of traffic and environmental issues between the Do-Somethingscenarios, described below, and a baseline scenario.

In the Do-Minimum scenario only committed transport schemes and land-useproposals within the study area have been considered as shown in Figure 3.1.These are listed in Table 3.1.

Table 3.1 - Committed Highway Schemes Within Study Area

Scheme	Improvement
A428 Hardwick to Caxton Common	Dualling of existing A428
A1198 Papworth Bypass	S2AP bypass of Papworth village
Milton Junction	Safety Improvements
Access to Cambridge Science Park	Double right turning lanes
Milton Junction	Provision of dedicated left turn

Together with the schemes above it has been assumed that a replacementHuntingdon Viaduct and upgrading of the local road network around the proposedNorthstowe development will be required should the A14 Improvement scheme notbe implemented. These are described in more detail in the following sections.

Figure 3.1 - Do-Minimum Option

HUNTINGDON VIADUCT

Huntingdon Railway Viaduct is a six span structure carrying the A14(T) over theB1514 Brampton Road and the East Coast Main Line Railway on the western sideof Huntingdon. It was constructed circa 1975.

The Do-Minimum assumption for assessing the A14 improvement options is basedon the premise that the existing Huntingdon Viaduct will be replaced. It is proposedthat the viaduct will be replaced with a structure similar to that shown in drawingnumber 5021044/DR/BR/023.

NORTHSTOWE

The proposed Northstowe development is not a committed scheme itself. However,based on information set out in the County Structure Plan it has been assumed ascommitted for the purpose of the Do-Minimum scheme.

To accommodate the increased traffic flows that will result from Northstowe the Do-Minimum Option assumes that the B1050 Hatton's Road carriageway will beupgraded to Dual 2 Lane All Purpose (D2AP) road between Northstowe and theexisting A14 and that this will feed into a new Bar Hill Junction. Improvements tothe local road network will also be made by running a local access road adjacent tothe northern perimeter of the A14 between Bar Hill and Dry Drayton, as shown inFigure 3.2.

3.1.2 Blue Route Option

A14 MAINLINE

The Blue Route Option is similar to the Targeted Programme for Improvement(TPI) route as detailed in CHUMMS. It is shown on Figure 3.3 and in more detail ondrawing number 5021044/DR/HW/101 and 102. As the drawings show, theproposed A14 mainline leaves the existing A14 corridor to the west of the A1/A14Brampton Hut Junction and runs adjacent to both sides of the A1 creating a singletraffic corridor. The eastbound carriageway crosses the A1 (options have beendeveloped to cross either over or under) and runs to the east whilst the westboundcarriageway remains to the west. The two carriageways join one another to thesouth of Brampton and the route moves eastwards passing between the town ofBrampton and Buckden North Landfill Site. It then crosses the River Great Ouseand East Coast Mainline (ECML) railway and continues in an easterly direction tothe north of the Wood Green Animal Shelter and the villages of Hilton andConington. It passes to the south of Fenstanton and the closed Conington LandfillSite before tying into the existing A14 to the south of Fen Drayton.

Figure 3.2 - Northstowe Do-Minimum Option

Figure 3.3 - Blue Route Option Mainline

From this point the Blue Route Option comprises online widening of the existingA14 and the Cambridge Northern Bypass (CNB) to Fen Ditton with the exception ofa short section at Bar Hill. At this location the route moves offline to the north of BarHill between Lolworth Spring and the Girton Interchange by a distance of 110metres at its maximum point to allow a new junction to be constructed to replacethe existing one.

In locations, where the Blue Route Option involves widening the existing A14,provision will be made for local traffic in the form of a Local Access Road (LAR). Inmost cases, the LAR runs adjacent to the proposed A14 mainline and ties into theexisting A14 when the route option moves offline. This maintains the route of theexisting A14, which will be used for local traffic when the proposed scheme isoperational.

The alignment of the Blue Route Option is discussed in more detail in Section 4.2of this report.

Junction Strategy

The Blue Route Option has nine associated junctions, as listed below:

• Brampton Interchange
• Fen Drayton Junction
• Trinity Foot Junction
• Bar Hill Junction
• Dry Drayton Junction
• M11 Junction 14
• Histon Junction
• Milton Junction
• Fen Ditton Junction

Two junction strategies have been developed which include variants of each ofthese junctions together with alternative mainline cross-sections and Local AccessRoad layouts. These strategies are described in Section 4.2.2.

3.1.3 Purple Route Option

A14 MAINLINE

The Purple Route Option is shown on Figure 3.4 and in more detail on drawingnumber 5021044/DR/HW/103. As can be seen it follows the same route as theBlue Route Option from where it leaves the existing A14 at Brampton Hut to east ofthe Wood Green Animal Shelter. From this point the proposed A14 turns andtravels in a north-easterly direction before tying into the existing A14 to the west ofGore Tree Farm. It commences in an easterly direction along the route of theexisting A14, passing through Fenstanton and south of Fen Drayton. After passingFen Drayton the Purple Route Option runs along the same line as described for theBlue Route Option in Section 3.1.2 above.

JUNCTION STRATEGY

The Purple Route Option has nine associated junctions similar to those listed forthe Blue Route Option. The difference being that the Purple Route Option has ajunction at Galley Hill and no Fen Drayton Interchange.

Only one junction strategy has been developed for the Purple Route Option, whichis described in Section 4.3.

3.1.4 Orange Route Option

A14 MAINLINE

The Orange Route Option is shown on Figure 3.5 and in more detail on drawingnumber 5021044/DR/HW/104 and 105. As with the Blue and Purple Route Optionsthe commencement of the Orange Route Option is to the west of the existingBrampton Hut Junction with the A1. From here the route travels adjacent to thewest of the A1 and in doing so maintains one corridor of traffic in this area.

After crossing the A1 between Brampton and Buckden the Orange Route Optionpasses to the south of Buckden Landfill Site before crossing the River Great Ouseand East Coast Mainline. It continues eastwards to the south of the Wood GreenAnimal Shelter and north of the villages of Hilton and Conington. To the west ofConington is where the Orange Route Option begins to follow the same route asthe Blue Route Option, which it continues to do through to Fen Ditton.

JUNCTION STRATEGY

As with the Blue Route Option, the Orange Route Option has nine associatedjunctions, as listed below:

• Brampton Interchange
• Fen Drayton Junction
• Trinity Foot Junction
• Bar Hill Junction
• Dry Drayton Junction
• M11 Junction 14
• Histon Junction
• Milton Junction
• Fen Ditton Junction

Figure 3.4 - Purple Route option Mainline

Figure 3.5 - Orange Route Option Mainline

Two junction strategies have been developed which include variants of each ofthese junctions together with alternative mainline cross-sections and Local AccessRoad layouts. These strategies are described in Section 4.4.2.

3.2 Cost Estimates

3.2.1 Basis of Estimates

Estimated costs for each scheme option have been calculated using basicquantities measured from preliminary design information. Table 3.2 below providesa breakdown of the estimates and the sections that follow describe associatedspecial factors and additional costs.

Where it was not considered practical to develop the design to a standard enablingdetailed quantification, an assessment of quantities or suitable allowance has beenmade. Unit rates have been obtained from various reference projects and appliedto the quantities as appropriate.

Costs are estimated to third quarter 2001 (Q3/2001) to enable them to be readilycompared to the Highway Agency's current Scheme Budget and previousestimates prepared for the HA.

Table 3.2 - Route Option Cost Estimates

Scheme Element	Do-Minimum £m	Blue (Junction Strategy A) £m	Blue (Junction Strategy B) £m	Purple £m	Orange (Junction Strategy A) £m	Orange (Junction Strategy B) £m
Preliminaries	0.430	26.043	27.138	25.556	26.124	27.197
Roadworks	2.184	87.052	88.728	86.522	87.214	88.849
Earthworks	0.314	39.909	39.711	28.498	36.539	36.214
Structures	26.513	94.872	98.971	95.156	98.919	103.018
Land	0.042	6.548	6.590	6.889	5.971	6.013
SU	0.300	15.994	16.249	17.781	15.278	15.533
Preparation & Supervision	0.492	34.641	35.542	33.265	34.668	35.544
Contingencies/Allowances	2.264	227.70	231.123	220.889	227.645	230.967
TOTAL	32.539	523.759	544.052	514.556	532.358	543.335

3.2.2 Special Factors

PRELIMINARIES AND TRAFFIC MANAGEMENT

Based on recorded data from previous contracts an allowance of 8% of theestimated construction costs has been made for preliminaries, excluding trafficmanagement. Traffic management has been assessed on a route specific basis toreflect the complexity of on-line widening.

SITE CLEARANCE

Huntingdon Railway Viaduct carries the existing A14 over the B1514 BramptonRoad and the East Coast Mainline Railway on the western side of Huntingdon. Ifthe new A14 is constructed the existing A14 will be detrunked and the viaductremoved and replaced with an at-grade junction at Brampton Road. The costestimates for each route includes an estimate of the cost of demolishing the viaductand replacing it with an at grade junction. All the costs associated with thedemolition of the viaduct; including those for the junction earthworks and pavementhave been included under the heading of demolition within the site clearancesection of the estimate.

EARTHWORKS

As the area is predominantly agricultural an estimated depth of topsoil for removalhas been established as 300mm.

The amount of acceptable material likely to be obtained from cuttings has beenassessed from examination of the geological data to hand. It has been assumedthat all unacceptable material will be placed in environmental bunds to avoid thecosts associated with transport and deposition to landfill sites.

There is generally a shortfall of acceptable material. Potential sites for borrow pitshave been identified along the proposed routes and so it is assumed that a fairproportion of the shortfall will be acquired in this manner.

COMMUNICATIONS

The cost estimates include allowances for emergency telephones, traffic surveyequipment, Close Circuit Television (CCTV) and Traffic Control Centres (TCC)Scheme equipment. It is possible that funding for TCC systems may be moreappropriately obtained from other budgets, but with the work still being undertakenwithin the A14 Scheme.

3.2.3 Supplementary Costs

An estimate for soft landscaping has been made from experience of typicalprovisions for similar schemes.

Diversion estimates have been requested from the various utilities companieswhose apparatus will be affected. Where estimates were not forthcoming,provisional assessments have been included in the estimates.

Land Acquisition Costs are to be estimated by the District Valuer. Atkins haveprepared drawings of land take for the various options and this has enabled a moredetailed cost estimate to be produced than would have been possible when theScheme Budget was established. The land take is predominantly agricultural and arate of £7,000 per hectare has been obtained from the DEFRA (Department forEnvironment, Food and Rural Affairs) website. In addition, development land to thesouth of the Cambridge Northern Bypass has been identified. The developers haveplanning permission for homes on the site between Histon Interchange and theImpington Rail Bridge and compulsory purchase of a strip of land will be necessaryto allow widening at the location. The cost of acquiring this land has been reviewedand an approximate value included in the estimates.

The cost of compensation for noise (Part 1 Claims) is to be estimated by theDistrict Valuer. As we have no better information at this stage we have included theScheme Budget allowance for Part 1 Claims in the cost estimates.The allowance for Preparation and Supervision has been reviewed. Werecommend that a total of 13% of the value of the works be applied for this,comprising 8% for preparation and 5% for supervision.

3.2.4 Developer Contributions

Between Bar Hill and the M11 Junction 14, the scheme has been appraised tomake provision for proposed development at Northstowe. It is possible that acontribution will be received from the developers however the scale of such isunknown and therefore has not been taken into account in the cost estimates atthis stage.

3.2.5 Detrunking Existing A14

No allowance has been made in the estimate for detrunking the A14 except for theremoval of Huntingdon Railway Viaduct and the associated at-grade junction withBrampton Road.

3.2.6 Comparison of Estimates

The estimates in Table 3.2 show the Blue Route Option (with Junction Strategy B)as the most expensive and the Purple Route Option as the cheapest.Significant variances between the elemental estimates are commented on below.

EARTHWORKS

The earthworks required for the Blue Route Option is significantly higher than theothers due to the greater imbalance between cut and fill, resulting in a far greatervolume of imported material required.

Although the Blue and Purple Routes follow the same alignment at the westernend, the Purple joins the existing A14 alignment earlier and therefore utilises moreof the existing carriageway, thus reducing earthworks requirements.

STRUCTURES

The estimates for structures vary between the routes. The cost of overbridges,underbridges and viaducts for the Orange Route Option is approximately £4m morethan for the Blue Route Option. This is predominantly because of the longer viaducton the Orange Route Option spanning both the River Great Ouse and the EastCoast Main Line.

The Galley Hill junction, unique to the Purple Route Option, requires extensivereinforced soil walling between slip roads and the main line, resulting in asignificant difference in the estimate for retaining walls.

VAT

The A14 Improvement scheme is a combination of new road construction builtoutside the existing highway boundary, on which VAT is non-recoverable, andonline widening on land within the highway boundary, on which VAT is recoverable.Therefore, because the Purple Route Option has the greatest extent of on lineconstruction the total amount of VAT for this option is lower than the other routes.