Contact: Andy Harding, ext 7787

1. Summary

1.1 The following decision is sought:

That the attached Highway Maintenance Noise Policy (Appendix 1) outlining the circumstances in which quieter surfacings should be considered be approved and incorporated into the Highway Management Maintenance Plan.

2. Reason

2.1 To ensure that appropriate consideration is given to the issue of road noise when carrying out resurfacing works, taking account of speed and volume of traffic and residents likely to be affected. It also accords with the County Council's corporate aims, in particular Stewardship of the Environment.

3. Other Options Considered and Rejected

3.1 Setting of the intervention criteria has been based on the limited guidance available. Other options considered and rejected are set out below.

3.2 Using speed limits to control speed and hence noise (option 1)

Setting speed limits is a complicated issue in which road safety is of major importance. Setting speed limits to reduce road traffic noise may result in them being ignored by motorists who will be unable to see any obvious reasons for the limits. This will bring other speed limits into disrepute and put further pressure on Police enforcement resources.

3.3 Do nothing (option 2)

This was rejected on the grounds that it was inappropriate to ignore the reasonable environmental concerns of local residents when Hampshire County Council carry out highway resurfacing works.

3.4 A policy that would produce a greater use of `quieter' road surfacing regardless of the circumstances (option 4)

The use of quieter road surfacing materials needs to be assessed against a number of factors, not just the environmental benefits but also the implication for increased use of raw materials and their transport. Other relevant factors include value for money with regard to the durability of the materials, other technical benefits (eg skid and spray reduction), initial cost and ongoing maintenance costs. A policy that did not take these other factors into account was not considered appropriate.

4. Conflicts of Interest Declared by the Decision Maker or a Member or Officer consulted - None.

5. Dispensation Granted by the Standards Committee - Not applicable.

6. Reason(s) for the Matter being dealt with if Urgent - Not applicable.

Approved by: Date:

Councillor K B Estlin

7. Background

7.1 The County Council is seeking to adopt a Noise Strategy, building upon the approach which was briefly outlined in the Local Transport Plan (LTP) (chapter 5 page 143). The need for a comprehensive Noise Strategy was recognised in the LTP and the strategy will be designed to complement various initiatives being developed both nationally and in Europe.

7.2 Within Europe, noise was recognised as an important issue in a paper published in 1996 which concluded that 20% of people in Europe were exposed to unacceptable levels of noise. In July 2000 a draft directive was published relating to the `Assessment and Management of Environmental Noise' focusing on road, rail, air traffic and industry. This is currently under consideration by the European Parliament and is likely to lead to legislation being introduced on environmental noise.

7.3 Within Britain, the Rural White Paper issued in November 2000 included a commitment by the Government to develop a policy on noise with the production of a National Ambient Noise Strategy. To assist in its production, research on noise mapping has been commissioned that will assess levels of environmental noise as well as considering public attitudes. This mapping exercise, which should be completed by 2004, should enable policy to take account more accurately the implications of noise sources, particularly in rural areas and is therefore seen as being very useful for the County Council in developing its own strategy.

7.4 The Hampshire County Council Noise Strategy has been developed in the light of national and European guidance and will in particular address issues related to the impact of traffic noise. Noise from traffic is principally generated by engine noise or vibration on the road surface and is significantly affected by speed and traffic volumes; in general, higher speeds and volumes will lead to greater levels of noise. There are two main ways in which this can be addressed, either by reducing the noise at source or by deflecting noise which is produced away from sensitive areas.

7.5 In advance of the Strategy the County Council is already tackling transport noise pollution issues and developing an approach to noise abatement incorporating a range of measures. These will be expanded and built upon as the Strategy is developed and include:

(i) road improvement design;

(ii) land use planning and traffic management;

(iii) staff transport plans;

(iv) improved vehicle technology;

(v) environmental enhancement;

(vi) monitoring and assessment; and

(vii) a full review of Highway Maintenance Policies.

7.6 It is intended that once the draft Strategy is produced a further report will be brought for decision, following which it is hoped to subject the Strategy to a wide ranging consultation encompassing a range of interested bodies, stakeholders and the general public.

7.7 It should be noted though that the proposed EC directive to map and tackle noise levels will initially target urban areas with more than 250,000 inhabitants, major roads (presumably motorway and trunk roads) and rail routes. None of Hampshire's urban centres would therefore be covered by the initial scope of this directive.

7.8 In the meantime increased media attention towards road noise; greater use of quieter road surfaces, particularly on the trunk road network where it is now policy to use surfaces 2dB(A) quieter than hot rolled asphalt; and recent Government proposals concerning monitoring and reduction of road noise have all led to greater public awareness of this issue. This has led to an increased number of complaints regarding new surfaces and requests to consider quieter surfaces on existing roads.

8. Measurement and Regulations

8.1 In order to reflect the perceived noise level the dB(A) weighting has been adopted to measure traffic noise. This takes account of the frequencies of road noise that are most readily detected by the human ear. Noise levels are measured over an 18 hour period and are quoted as the arithmetical mean of the noise level which is exceeded for 10% of the time in each of the 18 one-hour periods.

8.2 The dB scale is logarithmic and therefore an increase in 1 dB(A) is equivalent to an increase in traffic flow of 25%. Doubling the volume of traffic would increase the noise level of 3 dB(A).

8.3 An indication of the level of typical common sounds on the dB(A) scale (taken from the Design Manual for Roads and Bridges Volume 11) is attached as Appendix 2.

8.4 The Noise Insulation Regulations identify when properties are entitled to noise insulation following major roadworks or for new roads. There is entitlement to noise insulation if the following conditions are met:

(i) the combined expected maximum traffic noise level from the new or altered highway must not be less than 68 dB(A);

(ii) the noise level is at least 1.0 dB(A) more than the total prevailing noise level prior to the works; and

(iii) the contribution to the increase in the noise level must be at least 1.0 dB(A).

8.5 It should be noted though that there are no similar statutory requirements relating to increases in traffic noise due to routine maintenance of the highway network. There are however regulations relating to other alterations to the highway.

9. Assessment of Road Traffic Noise

9.1 Traffic noise is made up of two components, noise generated directly by the vehicle (engine, transmission and exhaust) and noise from the tyre/road interface. At speeds lower than 50 kilometres per hour (km/h) the majority of traffic noise is attributed to the vehicle, however at higher speeds the tyre/road noise becomes more significant. The amount of noise generated is dependent on tyre characteristics, vehicle speed and volume, road surface texture and road surfacing material characteristics.

9.2 The maintenance engineer has little control of the above factors, other than the surfacing elements, and possibly vehicle speeds. Generally it is accepted that porous asphalts provide the lowest noise levels, followed by other negative textured materials, asphalt and multiple surface dressings, traditional surface dressings and concrete in ascending order.

Table 9.2

Note: `Negative texture' surfacings are those in which the surface is generally smooth but with voids or hollows in. Tyres grip the surface by pressing down into the voids, unlike `positive texture' in which the aggregate protrudes up from the surface and presses into the tyres. `Positive texture' tends to be more noisy when vehicle tyres pass over them.

9.3 Experience in Hampshire broadly supports this assessment. For the Bentley Bypass carrying 16,000 vehicles per 18 hour flow at 90 km/h, the original porous asphalt was assessed at 75.4 dB(A), whilst the safepaving (negative texture) was assessed at 78.5 dB(A). Furthermore, testing on the Alresford Bypass following a 14 millimetres racked in surface dressing gave recordings of 79.7 dB(A) for a traffic flow of 12,000 vehicles per 18 hour for similar speeds. After further surface dressing works, comparable to a multi-layer dressing, levels were assessed at 74.5 dB(A). Whilst both appear higher than the predicted figures in graph 4.3 (Appendix 3), relative to each other they appear correct. Even allowing for an increase of 1.0 dB(A) to reflect the lower traffic level on the Alresford Bypass, the new level of noise would appear to have been significantly reduced to a level more comparable with negative texture surfacing. Further tests will be carried out after additional sections of the bypass are treated.

10. Acceptable Levels of Road Noise

10.1 Whilst there are no definitive requirements for levels of road traffic noise with respect to maintenance works, using the Noise Insulation Regulation figure of 68 dB(A) adjacent to a building (if this is considered an acceptable level) and assuming limited ground absorption it is possible to relate this figure to roadside levels, as shown in table 10.1.

Table 10.1

Note: Figures dependent on site characteristics

10.2 The Planning Policy Guidance `Planning and Noise' however states that insulation packages supplied under the Noise Insulation Regulations are inadequate for road traffic noise levels of 78 dB(A) and above at the façade. This would equate to roadside levels as indicated below.

Table 10.2

Note: Figures dependent on site characteristics

10.3 Given that insulation packages would have inadequate effect within these roadside levels, they should perhaps be considered the maximum roadside noise levels.

11. Impact of Practice Changes

11.1 In addition to the concerns regarding increases in traffic noise due to new surfacings, consideration should also be given to the County Council's Corporate Strategy and the long-term maintenance liability and environmental effects of opting to reduce road traffic noise by using quieter surfacings.

11.2 Whilst it is accepted that thin surfacings and porous asphalts reduce road traffic noise, there is a concern that there are often disbenefits associated with sustainability of the widespread use of these materials. Additionally, traffic disruption is likely to be higher for thin surfacings than for surface dressing.

11.3 It can be seen in graph 6.5 that the condition of the network remains relatively constant over a period of time as successive treatments are carried out as they are required. In the case of a conventional surfacing regime, in the `ideal' situation, roads are routinely surface dressed at regular intervals before being resurfaced. In the case of thin surfacings however, intermediate surface dressing is not possible if the noise characteristics are to be maintained.

11.4 If typical costs are put against these `ideal' regimes, the theoretical change to using thin surfacings is likely to mean an increased cost of 40%. Similarly, usage of materials is also likely to increase by approximately 40%.

11.5 It should be noted however that, as shown in graph 6.5 (Appendix 4), the practised regime for conventional maintenance has historically not attained the frequencies of the ideal intervention due to limited funding levels. Whilst this has not had a significant effect on much of the traditionally surfaced network, the implications of delaying intervention on roads surfaced with a noise reducing surface is currently not known.

11.6 In addition, if thin (quieter) surfacings are used, a double salt application is recommended during icy conditions, which not only cost more but the additional salt will cause more harm to the local environment.

11.7 One other issue to consider is the effect of quieter surfacings on driver behaviour. It is generally accepted that vehicle speeds can and do increase as the sensation of speed is reduced with the reduction in road noise. This may have an effect upon road safety and accident levels.

12. Options

12.1 In order to consider the effects of the possible changes to the current maintenance policy, the following options have been examined.

Option 1

12.2 A radical step would be to consider reducing traffic speeds after maintenance works, such as through rural villages, where the effects of increases in noise due to a new surface could be offset by reductions due to lower speeds. Graph 4.3.

Option 2

12.3 If the policy continues that decisions on surfacing choice are based solely on engineering requirements, the number of complaints is likely to rise given the increasing awareness of the general public and changes in the Highway Agency Policy (2.7). However, the cost implications would be minimal, relating to administration of complaints only.

Option 3

12.4 Assuming that a change in policy would not affect the majority of the urban network, which is defined as roads with less than a 40 miles per hour speed limit, the remaining network could be treated with the aim of not exceeding a maximum noise level at roadside in the vicinity of properties. Assuming a maximum level of 78 dB(A) at roadside, graph 4.3 would indicate that traditional materials would maintain this level for roads carrying up to 32,000 vehicles per 18 hour day. This level of traffic is only exceeded on about 50% of the `A' road network, approximately 66% of which is rural, and only a small proportion of which has adjoining properties.

12.5 An assessment of the implications of adopting this maximum level assuming 30% residential or for continuity has to be treated is as follows:

(i)	additional annual cost over existing methods	£94,000
(ii)	estimated additional cost comparing `ideal' regimes	£287,000
(iii)	additional annual material usage over existing methods	400 tonnes
(iv)	additional annual material usage comparing `ideal' regimes	736 tonnes

Option 4

12.6 If the lower figure in line with the `Calculations of Road Traffic Noise' were to be used (68 dB(A) at building) equivalent to typically 74 dB(A) at roadside, a greater proportion of the `A' road network and other roads are likely to be affected. Although, again, not all of these roads are residential and therefore perhaps only 20% of these roads are directly affected. For this assessment all rural `A' roads, and 25% of `B' roads have been considered, subject to the proportion with adjoining properties.

(i)	additional annual cost over existing methods	£235,000
(ii)	estimated additional cost comparing `ideal' regimes	£304,000
(iii)	additional annual material usage over existing methods	1000 tonnes
(iv)	additional annual material usage comparing `ideal' regimes	1850 tonnes

13. Conclusion

13.1 The effects of maintenance operations to resurface roads can have a significant impact on road traffic noise which in some cases can cause annoyance to adjoining properties.

13.2 Whilst there are definite benefits in moving towards blanket use of quieter road surfacing materials now available, the disbenefits of this in terms of real costs and environmental and possible road safety costs preclude this option. However, there is a need in certain circumstances to use quieter surfacings and therefore the effects of surfacing operations should be considered carefully to ensure that appropriate materials are used, not just to meet engineering requirements but also those of the environment.

13.3 The circumstances in which quieter surfacings should be considered for use are contained in the attached Highway Maintenance Noise Policy.

7233/ASH

APPENDIX 1

HIGHWAY MAINTENCE NOISE POLICY

1. Introduction

1.1 This procedure shall be read in conjunction with the Highway Maintenance Noise Strategy.

1.2 The Engineer responsible for designing the road maintenance scheme shall be responsible for ensuring that consideration is given to the implications of any increase in road noise.

2. Procedure

2.1 The direct effect on adjoining properties should be considered before a decision on choice of surfacing is finalised unless any of the following requirements are met. Table 2.1.5 can be used to assist with assessing the reduction effect of distance.

2.1.1 Traffic speeds are likely to be below 30 miles per hour

or

2.1.2. roadside noise levels are predicted to be below 78 dB(A) after the works

or

2.1.3 where traffic flows are likely to be below 32,000 vehicles per 18 hour day

or

2.1.4 where similar materials are specified with the same of lower texture depths and therefore there is likely to be no increase in roadside noise

or

2.1.5 where there are no properties in the immediate vicinity of the surfacing works. See table 2.1.5.

Table 2.1.5