Busy four-lane highways create noise and Waka Kotahi NZ Transport Agency works hard to minimise disruption to neighbours – both during construction and once operational.
We engage with landowners long before a project starts, so they understand the impacts of a highway near their home.
The Waikato Expressway project needs to meet strict obligations around noise – especially to residential properties built before the highway was given consent. Decibel levels are set in the project consent conditions and must be met when the highway opens to traffic. Noise monitoring is done to make sure of that.
There are various tools for moderating road noise and a quieter asphalt surfacing is the main one.
Another option is to build noise walls adjacent to the highway or to carry out building modifications to existing dwellings to reduce the noise inside.
People who are used to a quiet rural environment may find the highway noise more than they expected. In the past, expressway sections have opened on chipseal which is much noisier and required 12 months of traffic before the final asphalt surface could be applied.
Innovations in roading technology mean that asphalt can now be applied before the road opens to traffic. The Huntly section opened in 2020 with asphalt in place and the same will be done for the Hamilton section.
In another measure to reduce noise on the Hamilton section, rumble strips will not be laid within in 100m of houses.
New subdivisions have sprung up next to the Hamilton section – but because our designation was already in place (ie the expressway was known about) any noise mitigation is the responsibility of the developer and council.
You can find a lot more about the Waka Kotahi policies, plans and guidelines for noise and vibration.
Traffic flows and noise levels
Hamilton noise monitoring report by Marshall Day Acoustics – November 2022 [PDF, 5.6 MB]
Contact us
If you have specific questions about noise, please get in touch with our Environment team at environment@nzta.govt.nz
