Highways Agency

• 1. introduction
• 2. scheme proposals
• 3. engineering assessment
• 4. environmental assessment
• 4. environmental assessment (continued)
• 4. environmental assessment (continued)
• 4. environmental assessment (continued)
• 4. environmental assessment (continued)
• 4. environmental assessment (continued)
• 4. environmental assessment (continued)
• 4. environmental assessment (continued)
• 4. environmental assessment (continued)
• 4. environmental assessment (continued)
• 4. environmental assessment (continued)
• 5. traffic and economic assessment

4. environmental assessment (continued)

4. Environmental Assessment (continued)

4.2 Traffic Noise and Vibration

4.2.1 Introduction and Method of Assessment

NOISE

Noise annoyance is defined by the World Health Organisation as 'a feeling of displeasure evoked by noise' and mainly effects people when they are in their homes or when they are in the streets. Individuals vary considerably in their sensitivity to traffic noise therefore the relationship between noise exposure and nuisance adopts the concept of an average or community annoyance rating for each noise level. The rating differs between a sudden and gradual (steady state) increase in noise. The sudden increase giving rise to a greater percentage of people annoyed compared with the same noise increase for steady state conditions.

A Stage 2 traffic noise and vibration assessment has been undertaken for the alternative options for a new route and widening works for the A14 between Ellington and Fen Ditton. Preliminary predictions of noise levels have been made for the options considered in the opening year (2010) Do Minimum, and a future year (2025) for the Do Minimum and Do Something scenarios. The effects of known development schemes (including that proposed at Northstowe) have been taken into account.

DESCRIPTIONS FOR THE MAGNITUDE OF EFFECT

The response of the human hearing system is logarithmic rather than linear in behaviour, and able to detect a noise level difference of about 1 dB(A) between two steady sounds, when presented in rapid succession under controlled laboratory conditions. The smallest change in environmental noise that is generally noticed by an individual over a period of time is about 3 dB(A). A 10 dB(A) change approximates to a subjective doubling or halving of loudness.

STUDY AREA

The study area has been split into two levels of detail:

• A fully-modelled area close to the existing A14 and CHUMMS road corridors;
• An indicative area covering roads where there may be significant changes in traffic flow.

TRAFFIC DATA

Existing 2003 traffic flows for the section of the A14 covered by this study are in range between 15,000 to 25,000 (18-hr AAWT) west of the A1 near Brampton, up to 80,000 between the A1 and M11 and over 100,000 east of the M11 junction. It is known that traffic congestion can occur frequently causing a speed reduction which has been taken into account. It can be shown that there is approximately 1dB reduction for each 10km/h speed reduction from 108 to 48km/h.

This noise assessment has been carried out for the CHUMMS Strategy and the Alternative Option only and the forecast traffic flows and speeds have been taken into account.

METHOD OF ASSESSMENT

At this stage there has not been any consultation with local authorities regarding issues on noise.

CRTN is the methodology used to determine entitlement under the Noise Insulation Regulations 1975 (as amended 1988) and is the accepted method for the prediction of traffic noise in the UK.

To provide information on the existing noise levels in rural areas where it was not reasonably possible to carry out noise calculations, a preliminary noise survey was undertaken in October 2003 by Atkins. These measurements concentrated on areas where existing levels are low or where local roads may have some effects.

The incremental effect of each option was calculated as outlined in TAG in order to estimate the number of people that are likely to be bothered by increased noise.

• Noise contours were generated along the proposed composite alignments using CTRN;
• Areas exposed to 55dB or more have been identified.

LIMITATIONS

CRTN has been developed from extensive measurement data and validated out to distances up to 300 metres from trafficked roads. However some extrapolation is acceptable for planning purposes.

In the case of this study, extrapolated levels well beyond 300 metres from roads have been made in order to make the necessary determinations of the extent of noise impacts. It has generally been necessary to limit the extent of the study within areas where noise levels are 55dB or more. Such levels may be found as much as 1km from the A14. From limited measurements, some quiet rural areas exist where levels may be lower although, there is insufficient data to form a reliable objective comparison. However, indications of such quiet areas have been outlined under 'Baseline Conditions'. In order to make quantitative determinations with reasonable accuracy, it would be necessary to have further data at locations where noise levels are low. It would also be necessary to have more precise and certain data on road alignments and earth works to determine overall impact with greater accuracy.

In areas of open land that are enjoyed as a general public amenity, the effect of noise can be important. Guidance on noise is provided by the World Health Organisation (WHO). They have indicated that "daytime outdoor noise levels of less than 55 dB LAeq (approximately equal to 58dB LA10, (18 hour)) are desirable to prevent any significant community annoyance" and this has been restated in PPG 24 Planning and Noise - Noise exposure Categories: Explanation of Noise levels, paragraph 4, and page 11.

4.2.2 Baseline Conditions

GENERAL

The findings of the noise survey and calculated data has been used as the basis for comparison. These take into account the present effects of road surface conditions, a thin wearing course surface reduces noise by up to 3dB compared to a normal hot-rolled asphalt surface. Where speeds are less than 75km/h noise levels are 1dB lower.

All noise levels are in terms of LA10 (18 hour).

AREAS ADJACENT TO THE EXISTING ROUTE

A14 between Ellington and A1 near Brampton

The area is open countryside with isolated dwellings situated at some distance from these roads. However, noise levels from these are evident in most parts of the area with levels measured above 50dB except at Brampton Wood. Calculations confirm that most of the area of this woodland is below 50dB.

Levels of 60dB or more affect all areas within approximately 250m to 300m of the A14 and A1M but near the junction the combination of the two sources extends noise over a wider area than each road on its own. Levels of 55dB or more may extend as far as 600m from the A14 and 500m of the A1 but more near the junction.

A1 South of the A14 Interchange

Interchange The A1 between the A14 and Buckden Road Interchanges, affects the housing areas on western side of Brampton with levels in the low 60s dB at the nearest houses that are within 250m and 55dB or more up to 500m and in some places, greater distance near the junction.

A14 between A1 near Brampton and A141 near Stukeley Junctions

The present A14 affects the houses on the north side of Brampton with most above 55dB at up to 500m distance. At Hinchingbrooke Country Park, which is partly on ground rising from the road, noise levels of 55dB or more are found within 700m each side of the A14 with additional noise from the B1514 thus affecting most of the park and the racecourse.

A14 between A141 near Stukeley and A1198 Junctions

On the northern side of the A14, which has a noise reduced surface, there are the extensive housing areas of Stukeley and the southern side of Huntingdon. Taking into account the present environmental barriers and bunds, noise levels are 60dB or more within 200 to 250m of the A14 and 55dB or more within approximately 700m.

Parts of Hinchingbrooke Hospital are exposed to levels above 55dB. Within the areas to the east of the B1514, those to the north of the B1044 and west of the A1198, there are further areas of housing close to the A14. Taking into account the present environmental barriers, noise levels are 60dB or more within 350m of the A14 and 55dB or more within 800m and further where there are additional contributions of noise from other roads.

A1198 to A1096/B1040 Galley Hill Junctions

The houses on both sides with housing developments on the southern side of Hemingford Abbotts and Hemingford Grey experience 60dB or more within approximately 250m of the A14, which has a noise reduced surface and 55dB or more within approximately 500m. The more distant effects of traffic noise with levels of 50dB or more affects the southern side of Hemingford Grey.

A1096/B1040 Galley Hill to west of B1050 Bar Hill Junctions

Noise levels are 60dB or more within 250 to 300m of the A14 and 55dB or more within 500 to 600m but less within the housing at Fenstanton on account of the existing environmental barriers.

Fen Drayton is affected by distant A14 noise with levels of approximately 50dB on the southern fringes.

B1050 Bar Hill to M11 Interchange at Girton

Noise levels are 60dB or more within 300m of the A14 which has a noise reduced surface and 55dB or more within 500 to 600m but less within the housing area of Bar Hill.

Lolworth is affected by levels in the low 50's dB and some of the northern fringes of Boxworth may be above 50dB due to the local road even where they are unaffected by local traffic. However, at Conington houses away from local traffic experience noise levels of less than 50dB.

A14 from Girton to B1047 Fen Ditton

Noise levels are 60dB or more within 300m of the A14 and 55dB or more within 600m. However at Girton, where the road is in cutting, houses up to 180m are affected by levels of 60dB or more with those closest in the 65 to 70dB range. Similar levels affect the nearest houses around Histon Junction.

AREAS ADJACENT TO CHUMMS STRATEGY

The following applies to both the CHUMMS Strategy and the Alternative Proposal.

A14 between Ellington and A1 south of Brampton

Noise levels south of the landfill site and Station Farm are isolated houses likely to be in the low 50's dB or lower in parts.

A1 to Great Ouse Bridge near Offord

Open areas to the south of Offord Cluny to the south are likely to be in the 40's dB with little effects from major roads.

Offord to A1198 south of Wood Green Animal Shelter

Open areas and isolated buildings that exist with noise levels are in the upper 40's and low 50's. Close to local roads, such as the A1198, levels can be much higher.

South of Wood Green Animal Shelter to Fenstanton

Open areas to the north of Hilton where levels are in upper 40's and low 50's dB.

Fenstanton to Bar Hill

The open countryside to the south of Fenstanton and to the north of Conington have some noise influences of the existing A14 with levels of 55dB or more within 550m of it and 60dB within 250m.

CHANGES BETWEEN PRESENT AND OPENING YEAR (2010)

Changes between the present and 2010 will be related to traffic growth and any effects of resurfacing the existing roads with quieter surfaces. For the purposes of the following, the 2010 situation is taken as the basis for comparison.

4.2.3 Key Issues/Areas

Both the options would introduce noise into rural areas that are presently little affected by noise. However, the impact of noise will be dependent upon how quiet the present area is. This is dependent on:

• The distance from the existing A14 and A1 (M).
• Effects of traffic on local roads.
• Benefits of providing environmental barriers

This is an area which is largely low-lying or generally undulating. There are few road cuttings and most of the existing A14 is near or slightly above the surrounding ground level. As a result, noise from this road tends to propagate over wide areas as described previously.

There would be limited opportunities to place any of the options within significant cuttings or provide substantial earth bunding so as to provide a significant reduction in the lateral spread of noise. Consequently, any option considered should be sited as far as possible from where people live. However, this would have the effect of introducing noise into areas of countryside that are presently subject to low levels.

4.2.4 Mitigation Measures

On the basis of current Highways Agency advice, resurfacing with a thin wearing course (TWC) would reduce noise levels by 2.5dB(A).

Acoustic fences and/or earth bunds could reduce noise levels by up to 15dB(A) if they are of a sufficient size. However, where screening is only partial, noise reductions of 5dB(A) or less would be expected and beyond 300m are unlikely to have much effect, particularly where the road is at grade and the surrounding area is level.

Noise mitigation will be required in a number of areas for both options as outlined and it is assumed that all environmental noise barriers would be reflective. Mitigation has not been considered for the exiting A14 except where improvements are proposed.

4.2.5 Assessment of the two Options

This Scheme Assessment Report provides details of the effects of the CHUMMS Strategy and Alternative Option only.

The options are compared with the 'Do Minimum' scenario using the TAG criteria and, where appropriate, taking into account the outlined mitigation measures described previously. Indicative noise contour maps have been prepared showing the free-field noise levels in 5dB bands from 55 to 75dB at 5m above existing ground levels within a limited distance from the road (generally no more than 500m from the road where there are noise sensitive areas). In addition, a noise contour map has also been prepared for the 'do minimum' scenario. All situations relate to 2025.

All options include the effects of noise from the section that comprises the Cambridge Northern Bypass. In the case of the 'do minimum' scenario, this considers the present road layout and necessary changes that would need to be made by 2025. For the 'do something' options environmental barriers would be acoustically absorptive except where it has been shown that conventional reflective barriers would cause no adverse impact to people.

DO MINIMUM

By the assessment year (2025) traffic increases would, in general cause noise levels to be 1 to 2dB higher than those in the do minimum (2010). However, where traffic congestion increases, such noise increases may not occur.

It is expected that all of the A14 would be resurfaced in a quieter material by the year 2025. In addition, a new single carriageway road link would be built between Bar Hill and Dry Drayton. A new Huntingdon Viaduct would be built on the line of the present one.

The number of properties that would be within 300m of the centreline of the A14 is 555 at between 0-100m, 1,232 at between 100-200m and 1,712 at between 200-300m.

ROUTE OPTIONS

The CHUMMS Strategy and Alternative Proposal have been examined. To illustrate the general impact of these and the 'Do Minimum' situation, indicative 1:50,000 scale noise contour maps have been prepared. These are included in the EAR.

The following table summarises the effects of noise within the study area and where houses are affected by noise levels of 55dB or more.

ASSESSMENT

The number of properties that would be within 300m of the centreline of new roads is 215 at 0-100m, 432 at 100-200m and 939 at 200-300m. This applies to both the CHUMMS Strategy and Alternative Proposal.

On the basis of TAG and compared with the 'Do Minimum' situation 2024 there would be a net decrease of 407 people that would be annoyed by noise with the CHUMMS Strategy. With the Alternative Proposal there would be a net decrease of 149. On balance, the CHUMMS Strategy is the most favourable. However, this assessment does not include people who are affected by changes in noise where levels do not reach 55dB.

OTHER AREAS AFFECTED BY NOISE CHANGES FROM TRAFFIC RE-DISTRIBUTION

Some areas outside the route corridors above are expected to be affected by changes in traffic. The extent of these traffic changes and the consequential effects on traffic noise are dependent on the layout and location of the junctions required to gain access to the A14 route. The following table outlines the effect arising from the two options considered.

CHUMMS Strategy

The extent of expected changes in noise of 3dB or more in the case of CHUMMS Strategy are extensive as outlined in the following table.

Alternative Proposal

By 2025, the effects of noise changes outside the A14 corridors with the Alternative Proposal would be much less extensive than and there would be only be 3 to 5dB decreases to houses near Park Lane, School Hill and High Street between Bell Hill and Station Road.

The Alternative Proposal would require the rebuilding of the viaduct after the new route is operational. This would mean that the effects of noise outside the A14 route corridors for interim situation would essentially be as for the CHUMMS Strategy.

4.2.6 Summary and Conclusions

EXISTING SITUATION AND DO MINIMUM

At present there are a large number of people affected by noise arising from the A14 between Ellington and Fen Ditton. There are almost 3,500 houses within 300m of the present route between these places and by 2010, over 1,850 are affected by noise levels from the A14 of 60dB or more if no scheme is built and almost 1,950 by 2025.

OPTIONS AND ASSUMPTIONS

Two options have been assessed, the CHUMMS Strategy and an alternative that retains the existing A14 as a through route, the Alternative Proposal.

For both options, the same simple 2m or 3m high environmental noise barriers or earthworks have been considered for mitigating noise from the new roads. Both options assume quiet road surfaces.

The effects of noise changes in areas situated some distance from the A14 where levels are below 55dB has not been carried out at this stage. In order to make such determinations with reasonable accuracy, it would be necessary to have further data at locations where noise levels are low. It would also be necessary to have more precise and certain data on road alignments and earth works.

GENERAL EFFECTS OF THE OPTIONS

The CHUMMS Strategy would remove much of the impact of noise at Godmanchester. However, risks of noise increases remain at the quiet areas of Buckden and Offord Cluny with further risks at Hilton, an area where present levels are low.

East of Trinity Foot the scheme is on-line and there are opportunities to mitigate noise at most locations that are within 200 or 300m of the route. Some barriers would provide significant reductions on present levels at those houses most affected. However, beyond that distance and where other roads have influence, noise levels may be increased due to the increased traffic, reduced congestion and limited extent that barriers could reduce noise.

NOISE CHANGES FROM TRAFFIC OUTSIDE THE PRESENT A14 AND THE OPTIONS

Outside the A14 route corridors, the construction of the CHUMMS Strategy would affect increases of 3dB or more at over 2,300 houses with decreases of 3dB or more at less than 230. The Alternative Proposal would have much less effect with just 57 houses benefiting from a 3dB or more decrease.

4.2.7 Conclusions

The CHUMMS Strategy would mean that there would be a net reduction of 407 people annoyed by noise compared to 149 with the Alternative Proposal.

In the areas of the A14 corridors, over 1,000 houses would be affected by a noise increase of 1dB or more with the CHUMMS Strategy compared to over 1,400 with the Alternative Proposal. The CHUMMS Strategy would effect noise decreases of 1dB or more at over 4,000 houses (equivalent to approximately 9,600 people) compared to just over 2,100 (5,040 people) with the Alternative Proposal.

Away from the A14 Corridor, the CHUMMS Strategy would affect increases of 3dB or more at over 2,300 houses (approximately 5,500 people) with decreases of 3dB or more at less than 230. These are concentrated on Brampton Road and the western quadrant of Huntingdon inner ring road, reflecting the changed access arrangements into Huntingdon with local traffic diverted off existing routes, and the A1 corridor. Reference should be made to paragraph 1.11 on traffic considerations.

The Alternative Proposal would have much less effect with just 57 houses (approximately 137 people) benefiting from a 3dB or more decrease and no properties would experience an increase of 3dB or more.