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Reverse sensitivity is the vulnerability of an established land use (state highway) to complaint from a newly establishing, more sensitive land use (new houses and other activities which might be disturbed by noise from a road). Managing reverse sensitivity effects is the joint responsibility of Councils, property owners and the NZ Transport Agency.

  • What is reverse sensitivity?

    Reverse sensitivity is the vulnerability of an established land use (state highway) to complaint from a newly establishing, more sensitive land use (new houses and other activities which might be disturbed by noise from a road). 

    In practice such complaints can compromise the established land use (in this case a road or state highway) by seeking restrictions on how or when it can operate. It can also mean the new sensitive land use is exposed to adverse effects if not appropriately managed.

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  • Why manage reverse sensitivity?

    Unfortunately, there is unavoidable noise and other effects associated with highway use, operation, maintenance and construction.

    Exposure to high levels of environmental noise has been linked to cardiovascular disease, cognitive impairment in children, sleep disturbance, tinnitus and annoyance. Sleep disturbance and annoyance - mostly related to road traffic noise, constitute the bulk of these effects.

    Noise may also reduce enjoyment of outdoor areas, such as gardens, decks and play areas.

    Tension can therefore arise between the Transport Agency’s need to operate and maintain a safe and efficient highway network and the desires of neighbouring land owners to enjoy their property free from interference or nuisance.

    While the Transport Agency takes care to manage unreasonable nuisance or interference, disturbance at sensitive receivers can still arise. Careful planning by managing reverse sensitivity issues creates social benefits in that it provides sensitive receivers with greater health and wellbeing, while still allowing the efficient movement of people and goods between communities.

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  • What is a noise-sensitive activity?

    A noise sensitive activity can be: 

    • any residential activity (including visitor accommodation and retirement accommodation)
    • any educational activity
    • any healthcare activity
    • any congregations within places of worship or marae.
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  • Who is responsible for managing reverse sensitivity effects?

    Managing reverse sensitivity effects requires a shared approach. This is because it is neither practical nor reasonable for landowners, developers, councils or the Transport Agency to assume sole responsibility.

    When landowners or developers establish a new dwelling (or other noise sensitive activity) or alter an existing dwelling next to the state highway (or a planned or designated road) they have a duty to mitigate the effects of their activity on the state highway. That is, they should ensure noise and vibration arising from a nearby road do not cause unreasonable disturbance to occupants of a dwelling - in particular, sleep disturbance.

    Councils have a duty to establish appropriate land use zoning, planning and consenting controls/requirements, primarily through district plans to make sure that the effects of noise sensitive activities on established or designated roads are managed. Careful and considered planning is pivotal to both protecting the environment and enhancing the quality of life for New Zealanders.

    The NZ Transport Agency is responsible for implementing good practice maintenance on existing roading infrastructure to manage noise and vibration arising from the road. For new roads or significant alterations to existing roads, the Transport Agency is also responsible for ensuring noise exposure and vibration impacts on existing nearby sensitive land use (e.g. an existing dwelling) is reasonable

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  • Why shouldn’t I build my house next to a state highway?

    Separation is often the most effective method of mitigating effects such as noise, vibration, vehicle emissions, lighting/glare and dust on people in houses. In general, the greater separation distances will result in reduced noise, vibration and other impacts, and improve outdoor amenity, such as the use of decks and gardens.

    The Transport Agency seeks for houses to be located outside of a state highway ‘buffer area’, which extends up to 40m from the traffic lanes. However, in constrained urban areas and in some other situations it can be impractical to restrict residential development to outside the desired ‘buffer area’.

    Houses can be built in the wider ‘effects area’, extending from 40m to up to 100m from the traffic lanes.

    In both the ‘buffer area’ and the ‘effects area’, the Transport Agency seeks controls to ensure dwellings and other noise sensitive activities are designed/treated to ensure internal noise levels are reasonable (to protect against sleep disturbance and provide reasonable indoor noise amenity). 

    In the ‘buffer area’, the NZ Transport Agency also seeks controls to ensure dwellings and other sensitive activities are designed/treated to ensure internal vibration levels are reasonable. 

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  • How much does it cost to acoustically treat my house?

    Each house (or other noise sensitive activity) in the ‘effects area’ and the ‘buffer area’ will require an assessment to confirm the acoustic treatment required to meet the recommended internal noise and vibration (‘buffer area’ only) levels.

    This is because site specific characteristics such as the terrain, location/orientation of the dwelling (or sensitive activity), traffic characteristics and road characteristics all influence noise exposure and vibration. The cost to acoustically treat a house will therefore vary from situation to situation. 

    As a guide, professional fees for an acoustic assessment of the design of a house to demonstrate compliance with the specified internal noise levels may cost $500 to $1500 but may be more for complex situations or where a vibration assessment is also required (activities in the ‘buffer area’).

    We have prepared a guide on building and property noise treatments, which is available on our website.  The intended audience for this guide is primarily engineers, architects and contractors, but may be of interest to homeowners or developers. This guide provides indicative (2013) costs for building treatments.

    State highway guide to acoustic treatment of buildings [PDF, 4 MB]

    The most common form of acoustic treatment is the provision of ventilation and cooling systems, which allow windows to remain closed to reduce interior noise levels. 

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  • How do I treat my house to comply with the requirements?

    The Transport Agency does not provide advice related to compliance with the internal noise and vibration level requirements.  We recommend you engage the services of a suitably qualified acoustics professional and a building design professional. 

    The most common form of acoustic treatment is the provision of ventilation and cooling systems, which allow windows to remain closed to reduce interior noise levels. 

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  • What tools are available to estimate building/dwelling noise treatment requirements.

    We have developed tools (calculators) and guidance for building and property noise treatments. The intended audience for these is primarily engineers, architects and contractors, but may be of general interest to homeowners and developers.

    The road-traffic noise calculator provides a prediction of exterior noise exposure at dwellings where the terrain, building and road are not complex.

    Road traffic noise calculator

    This calculator allows the internal noise level to be estimated based on the building construction and a specified external noise level (from the road-traffic noise calculator). Noise is predicted through the wall facing the road, and optionally through the roof, windows and doors. Both the total noise level and the path contributions are displayed.

    Internal noise calculator

    We have also prepared a guide on building and property noise treatments.

    State highway guide to acoustic treatment of buildings [PDF, 4 MB]

    The most common form of acoustic treatment is the provision of ventilation and cooling systems, which allow windows to remain closed to reduce interior noise levels. 

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  • What’s the best way to comply with the requirements?

    Separation and screening of a dwelling or sensitive activity from the road are the two best ways to comply with noise and vibration requirements.  This is because these methods improve outdoor noise amenity, for example for the use of gardens and decks etc. while also reducing or eliminating the requirement for building acoustic and/or vibration treatments. 

    Orienting and siting a building so living areas and especially bedrooms, are facing away from the road and/or are screened by terrain or other solid barriers will improve indoor noise levels. It can also be beneficial if primary outdoor amenity areas such as decks, gardens and play areas are screened from the road by the dwelling, terrain and/or other solid barriers.

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  • If I build a solid fence or wall will that block out the noise?

    In some instances, barriers such as walls, fences (no gaps between palings) or earth bunds may be all which is needed to comply with the internal noise level requirements. An effective barrier provides the benefit of not only reducing indoor noise levels but also outdoor noise levels, improving outdoor amenity. 

    Care needs to be taken during the design and location of barriers to consider urban design effects and maintenance requirements. To be effective, noise barriers for individual developments or dwellings need to join up with other noise barriers or extend wider than the area to be protected and should block line of sight from all parts of the dwelling to all parts of the road. Otherwise it may be necessary for the barrier to include return sections at each end of the barrier perpendicular to the highway. 

    We have prepared a guide for noise barriers which is available on our website.  The intended audience for this guide is primarily engineers, architects and contractors but may be of general interest to homeowners and developers.

    State highway noise barrier design guide [PDF, 3.7 MB]

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  • If I live next to a state highway can closing my windows help minimise noise?

    Yes, closing windows can significantly reduce the road-traffic noise heard inside a building. In many situations, this is the only measure required to achieve the required internal noise levels. 

    However, closing windows may compromise the natural ventilation and cooling of a building. Where windows need to be closed to achieve reasonable internal sound levels, mechanical ventilation and in some cases, cooling will be required. 

    Care should be taken when choosing mechanical ventilation to avoid systems that are excessively noisy.  Supplemental cooling may be required in some parts of the country that are hot in summer months.

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  • If I plant trees will that block out the noise?

    No, trees or shrubs generally provide minimal benefit in terms of reducing actual noise levels. However, there is usually a perceived reduction in noise when a road is visually screened by trees or shrubs which can have benefits. 

    Trees and shrubs are a practical method for visually screening the road, noise walls or bunds and reducing graffiti.

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