Frequently asked questions
When is a traffic assessment required for a development?
District plan rules set thresholds based on the number of dwellings or units, the trip generation of the proposed activity, the number of parking spaces, and whether a new or altered vehicle crossing is proposed onto an arterial or collector road. Above those thresholds an integrated transport assessment or a smaller traffic impact assessment is required with the resource consent application. Sites with sight distance constraints or steep access often attract scrutiny even below the thresholds.
What standards apply to road and access design?
Road geometry, pavement design and vehicle crossings are designed to the relevant council code of practice or engineering standard, supported by Waka Kotahi and Austroads guidance for geometry, pavement and intersection design. Private accessways and shared private ways are typically covered by the district plan and the council code, with requirements for width, gradient, turning and passing provision that vary with the number of lots served.
How is pavement design related to the ground investigation?
Pavement thickness is driven by the subgrade strength, usually expressed as a California Bearing Ratio value, together with the design traffic loading over the pavement life. The subgrade value comes from the ground investigation, so testing at subgrade level is needed before the pavement can be designed, and subgrade conditions are then verified on site at construction because a weaker subgrade than assumed means a thicker pavement or subgrade improvement.