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Auckland Transport

Road sealing Road sealing

Auckland Transport (AT) is responsible for sealing unsealed roads in the Auckland region.

After a road is sealed it can take a few weeks for the seal to fully set. During this time the seal can be damaged by large vehicles, heavy rain, heat or vehicles that brake suddenly, turn sharply or drive at high speeds. We monitor newly-sealed roads until they are set and rectify damage as it occurs.

Seal extensions

Sealing a previously unsealed road for the first time is known in the roading industry as a “seal extension”.

Auckland has 7,300 kilometres of legal road, of which approximately 868km (12%) is unsealed. 678km (78%) of the unsealed road network is in Rodney and the remaining 190km is located mainly in Franklin, Hauraki Gulf Islands, and Waitakere*.

Typically, 50,000 vehicles a day use Auckland’s unsealed road network.

* The Waitakere Ranges Heritage Area Transport Design Guidelines will be taken into account when considering the sealing of any unsealed roads in this area. These state that: “existing unsealed roads should remain in an unsealed state, unless there are overriding health or road-safety reasons”.

How we prioritise road sealing

matakana valley road unsealed

AT prioritises sealing unsealed roads using the criteria contained in the Seal Extension Guidelines, which have been reviewed by rural Local Boards.

The criteria considers traffic volume, including heavy commercial vehicles, houses and amenities close to the road, safety (traffic accidents), road gradient (steepness) and regional and local priority. Traffic volume is given the highest weighting for prioritisation as vehicle movements are the primary cause of dust.

The prioritisation produces a ranking of all the unsealed roads compared to the available budget in Auckland Council’s Long-term Plan (LTP). The LTP for the period 2015 to 2018 allocated $10m in total for sealing. This is sufficient to seal a total length of 12.56km or 1.5% of the total unsealed road length (sealing all unsealed roads has been estimated to cost more than $350 million).

Priority list of all unsealed roads

matakana valley road sealed
Images: Matakana Valley Road before and after road sealing.

AT has produced a priority list of all of the unsealed roads in Auckland. The rural Local Boards have reviewed this list.

Get the priority list of all unsealed roads in Auckland.

Current and future sealing work

Three roads from the Priority List of Unsealed Roads in Auckland, were identified for seal extension during the period 2015 to 2018. So far the sealing of Silver Hill Road and Takatu Road have been completed. Monowai Road Stage 1 construction is underway, after being held and maintained by the Contractor over the winter months of 2018. We expect Stage 1 construction to be completed by the end of 2018, and Stage 2 by June 2019. 

Three (3) roads have been identified, and confirmed for seal extension in the Council LTP for the period 2018 to 2021. These three (3) roads are:

  1. Wellsford Valley Road;
  2. Ahuroa Road; and
  3. Ngarewa Drive.

They are currently in the design phase.

    Cost of sealing

    There is no typical or standard cost per kilometre to seal an unsealed road. Sealing changes a road’s physical characteristics, a driver’s expectations and encourages higher speeds.

    To mitigate these changes, it is often necessary to widen the road, undertake geometric and safety improvements including increasing the radius of bends and corners, the provision of road markings and road signs, and strengthening the road foundation. Land acquisition or the construction of retaining structures is a feature of many sealing projects. It is also necessary to improve the collection and disposal of storm water to prevent water getting into the foundation layers. This prolongs the life of the sealed road.

    The annual cost of maintenance and renewals for a sealed road is approximately $18,500 per km, and for an unsealed road approximately $4,500 per km.

    Dust suppressants

    A trial of dust suppressants is being currently being carried out in Kaipara. The trial is evaluating 5 different pavement compositions to determine the best approach to introducing dust-suppressant solutions in the Auckland region.

    Find out more about the dust supression trial.

    For more information

    Contact Auckland Transport