Auckland Transport (AT) has a programme to progressively improve the performance of its unsealed road network.
We are responsible for the management and maintenance of around 7,300km of the road network. Approximately 800km of the network is unsealed and is operated as gravel roads. In general, gravel roads service sparsely populated rural areas.
Around 80% of Auckland’s gravel roads are within the Rodney area. The remaining 20% is located mainly in Franklin, Great Barrier Island, Waiheke Island, and Waitakere.
The previous programme to seal unsealed roads used a narrow prioritisation approach, relying on information that is difficult to collect and maintain. This programme also assumed that the best approach for each road was to implement a full seal.
Working with the affected local boards, we have developed new framework changing the approach to instead assess and identify the road issues and then apply an appropriate treatment based on these issues. This will mean an increased number of roads can be improved annually as a broader set of solutions are possible, beyond just sealing. Road seals remain part of this solution.
How we prioritise road sealing
The decision-making process involves:
- Assessing the strategic role of each road based on the Roads and Streets Framework and traffic volume.
- Assessing each road quantitatively and qualitatively based on a multi-criteria analysis which includes:
- safety – using gradient and crash data
- public health – using dwelling and amenity proximity
- natural environment – examining sensitive receiving environments
- climate change – looking at the risk of dust events
- cost – taken once treatment option is determined
- Establishing the priority order from the 5 criteria which are assessed as high, medium or low priority based on the score they receive.
As part of this, we will take into consideration any relevant local board plans or area plans that may help influence our decisions.
The treatment options available
The new approach also allows for a broad range of treatment options, rather than defaulting to a full seal, including:
- surface strengthening
- road widening
- safety improvements
- pothole, corrugation and drainage improvements
- dust mitigation
- full seal.
Roads will be assessed with the treatment option determined by the core issue affecting the road. If there are multiple issues, then we will select the highest rated treatment option and if warranted, we will seal roads.
Each road is prioritised by treatment type and funding is allocated according to relative priorities within each treatment group.
We will liaise with local boards to ensure the proposed treatment option is suitable for the unsealed road.
How this approach improves on the previous framework
The new approach is an improvement to the previous Seal Extension framework as it:
- uses more robust data, which is easier to keep up-to-date
- also uses qualitative information to be a more holistic appraisal of the roads
- offers broader treatments and relates solutions to problems
- considers and incorporates local needs and context, such as aligning with character needs and heritage protection.
We have updated our programme of unsealed road improvements based on the year 2020 datasets. This updated programme is based on the priority order that has come from this updated methodology.
AT funding is approved in three-year cycles. Based on these funding cycles, sections of unsealed roads that do not appear on the programme of unsealed improvements cannot be programmed for any improvement works at this time.