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  1. Home
  2. General
  3. Infrastructure Development Processes
  4. Quality Assurance Information Requirements
    1. QA-1 Resource Consent Application Requirements
    2. QA-2 Works Undertaken By or For a Council
    3. QA-3 Development Works Approval
    4. QA-4 Survey Plan (s223) Approval
    5. QA-5 Final Sign Off (s224c) Application Requirements
    6. QA-6 As-Built Information
    7. QA-7 Bonds and Maintenance Fee
    8. QA-8 Building Consent Considerations
  5. Design Standards
    1. DS-1 General Provisions
    2. DS-2 Streetscape
    3. DS-3 Reserves
    4. DS-4 Transportation Network
    5. DS-5 Stormwater
    6. DS-6 Wastewater
    7. DS-7 Water Supply
    8. DS-8 Public Lighting
    9. DS-9 Network Utilities
    10. DS-10 Natural Hazards & Earthworks
    11. DS-11 Road Zone/Road Reserve Occupancy
    12. DS-12 Building Consent Considerations
  6. Standard Drawings
    1. SD-1 General Provisions
    2. Street design diagrams
    3. T100 Perspective Drawings
    4. T200 Streetscape
    5. T300 Reserves
    6. T400 Transport Network
    7. T500 Stormwater
    8. T600 Wastewater
      1. T601-Manhole - Standard
      2. T602-Manhole - Shallow
      3. T603-Manhole - Ladder and Steps
      4. T604-Manhole - Precast 1050mmØ Lid
      5. T605-Manhole - Entry Fixing
      6. T606-Manhole - Standard and Raised Access Detail
      7. T607-Manhole - Inclined Access Detail
      8. T608-Manhole - Internal Drop
      9. T609-Manhole - External Drop
      10. TT610-Manhole - PE Pipe Connections - Wall Adapter and Pre-Cast Manhole
      11. T611-Manhole - PE Pipe Connections - Stub Flange and In-Situ Base
      12. T612-Manhole - PE Pipe Connections - Electrofusion Coupler and In-Situ Base
      13. T613 Manhole - PE Pipe Connections - Puddle Flange and Pre-Cast Manhole
      14. T614-Manhole - Access Detail in Carriageway
      15. T620-Rodding Eye - Shallow < 2.5m
      16. T621-Rodding Eye - Deep > 2.5m
      17. T630-Property Connection - Standard
      18. T631-Property Connection - Depth > 2.5m
      19. T632-Property Connection - Within Property
      20. T633-Property Connection - Outside Property
      21. T634-Property Connection - Entry to Wastewater Main/Manhole
      22. T637-Lateral Connection - Single Connection to Manhole
      23. T638-Lateral Connection - Two or More Connections to Manhole
      24. T639-Lateral Connection - Single Connection to Main
      25. T640-Lateral Connection - Two Connections to Main
      26. T641-Lateral Connection - Two Adjacent Connections to Main
      27. T642-Lateral Connection - Rear Lot Connection
      28. T643-Mains Connection - Saddle Connection
      29. T651-Bedding and Backfill Details
      30. T652-Anti-Scour Block and Trenchstop
      31. T653-Buildings Near Public Mains
      32. T654-Close Proximity - Retaining Wall Restrictions
      33. T660-Pump Station - Typical Site Layout
      34. T661-Pump Station - Elevation Section
      35. T662-Pump Station - Plan Section
      36. T663-Pump Station - Pedestal Base Plate, Pedestal Mounting, Valve Chamber and Riser Connection
      37. T664-Pump Station - Deflector Plate, Ladder and Plinth
      38. T665-Pump Station - Valve Extension Spindle, Spindle Guide and Handwheel
      39. T666-Pump Station - Cover Slab
      40. T667-Pump Station - Frame
      41. T668-Pump Station - Chamber Lid
      42. T669-Pump Station - Chamber Lid Padlock and Handle
      43. T670-Pump Station - Rising Main Entry to Receiving Manhole
      44. T671-Pump Station - 25mm Water Service Connection
      45. T672-Pump Station - Electrical - Standard 2 Pump Stn Without Soft Starters (1 of 2)
      46. T673-Pump Station - Electrical - Standard 2 Pump Stn Without Soft Starters (2 of 2)
      47. T674-Pump Station - Electrical - Standard 2 Pump Stn SMC - 3 Soft Starters (1 of 2)
      48. T675-Pump Station - Electrical - Standard 2 Pump Stn SMC - 3 Soft Starters (2 of 2)
      49. T676-Pump Station - Electrical - Standard 2 Pump Stn IMS2 Soft Starters (1 of 2)
      50. T677-Pump Station - Electrical - Standard 2 Pump Stn IMS2 Soft Starters (2 of 2)
      51. T678-Pump Station - Electrical - Standard 2 Pump Stn ISMC - 3 Soft Starters (1 of 3)
      52. T679 Pump Station - Electrical - Standard 2 Pump Stn ISMC - 3 Soft Starters (2 of 3)
      53. T680-Pump Station - Electrical - Standard 2 Pump Stn ISMC - 3 Soft Starters (3 of 3)
      54. T681-Electrical - 2 Pump Stn Mincas SMC-3 Soft Starters (1 of 2)
      55. T682-Electrical - 2 Pump Stn Mincas SMC-3 Soft Starters (2 of 2)
      56. T683-Pump Station - Electrical Cabinet
    9. T700 Water Supply
      1. T700-Water Supply Pipe Hierarchy
      2. T701-Water Supply - Looped and Linked Principal Mains
      3. T705-Water Main - Location at Intersections
      4. T706-Watermain - Location at Cul de Sac
      5. T707-Water Main - Rider Main to Main Connection
      6. T708-Water Main - Flushing Point
      7. T709-Water Main - Branch Valves and Hydrant Combinations
      8. T710-Water Main - Support for Asbestos Cement Main
      9. T713-Hydrant Surround
      10. T714-Hydrant Box
      11. T715-Hydrant Surround Blocks
      12. T716-Valve Surround
      13. T717-Valve Box
      14. T718-Valve Surround 75mm Concrete
      15. T719-Valve Surround 100mm Concrete
      16. T720 Valve Surround Heavy Duty Concrete
      17. T721-Anchor block for Sluice Valves on Mains
      18. T722-Anchor Block for Flanged Fittings on Mains
      19. T723-Thrust Blocks
      20. T724-Hydrant and Valve Marker Post
      21. T727-Water Meter - Type 1 and 2 Point of Supply Location Installation
      22. T728-Water Meter - Type 3 and 4 Point of Supply Location Installation
      23. T729-Water Meter - Fire System Connection With Potable Supply Installation
      24. T730-Standard 20mm Manifold Connection
      25. T731-Standard 20mm Manifold Connections - Plan View
      26. T732-Multiple 20mm Installations
      27. T733-20mm Connection Requiring Double Check Valve
      28. T734-20mm Connection Requiring RPZ Installation
      29. T735-25mm, 40mm or 50mm Meter Installation With Double Check Valve
      30. T736-<50mm Meter Installation with RPZ
      31. T737-Property Connection - 50mm Combination Meter Installation with Double Check Valve
      32. T738-Combination Meter Installation with RPZ
      33. T739 >50mm Combination Meter Installation with RPZ & Bypass Option
      34. T740-Property Connection - Secure Connection
      35. T741-Manhole - Class A Loading
      36. T742-Chamber - Class A Loading
      37. T743-Manhole - Class B Loading
      38. T744-Chamber - Class B Loading
      39. T751-Bedding and Backfill Details
      40. T753-Buildings Near Public Mains
    10. T800 Public Lighting
    11. AB As-Built Drawings
  7. Approved Materials
  8. Construction Standards
    1. CS-1 General
    2. CS-2 Site Clearance
    3. CS-3 Earthworks
    4. CS-4 Excavation
    5. CS-5 Excavation in Trench
    6. CS-6 Fill
    7. CS-7 Bedding & Backfill
    8. CS-8 Subsoil Drainage for Earthworks & Roads
    9. CS-9 Pipework
    10. CS-10 Pipe Fittings
    11. CS-11 Manholes & Rodding Eyes
    12. CS-12 Sumps
    13. CS-13 Trenchless Technology
    14. CS-14 Road Ripping
    15. CS-15 Road Pavement Layers
    16. CS-16 Kerb & Channel
    17. CS-17 Concrete Work
    18. CS-18 Carriageway Surfacing
    19. CS-19 Roadmarking
    20. CS-20 Berm Features
    21. CS-21 Street Structures
    22. CS-22 Road Maintenance
    23. CS-23 Grassing & Turfing
    24. CS-24 Vegetation Planting & Gardens
    25. CS-25 Reinstatement
  9. Inspection & Testing Requirements
    1. IT-1 General Provision
    2. IT-2 Streetscape
    3. IT-3 Reserves
    4. IT-4 Transportation Network
    5. IT-5 Stormwater
    6. IT-6 Wastewater
    7. IT-7 Water Supply
    8. IT-8 Public Lighting
    9. IT-9 Network Utilities
Infrastructure Development Code

DS-4.5 Conveyance


DS-4.5.1   Widths, Lengths and Grades

Drawing Ref: T400, T405

The following shall apply:

  1. Only Road Zones with a minimum width of 12m shall be accepted for vesting in Council.
  2. Road Zones with widths narrower than 12m will be private ways. Maintenance shall be the responsibility of the owners of the lots that are served by the private way.

DS-   Urban Roads

DS- Table 1: Design Requirements for Various Road Classifications applies to urban roads and private ways.

The following shall also apply:

  1. Carriageway widths shall be measured between kerb faces.
  2. The minimum Road Zone and carriageway widths shown in the table make no allowance for additional intersection requirements, batters, embankments or road widening for horizontal curves. Specific design is required for every intersection before Infrastructure Development Works Approval. This shall determine final boundary locations in order to provide acceptable sight distances.
  3. Carriageway width may be determined taking account of:
    1. Public transportation requirements.
    2. The likelihood of opposing traffic.
    3. The likelihood of continuous parking on both sides of the road.
    4. The likelihood of vehicles turning into driveways.
    5. Carriageway space for cyclists as covered in Austroads Guide to Traffic Management, Austroads Guide to Road Design and Austroads Guide to Road Safety.
  4. Where the stated requirements for private ways are not met, the applicant shall state in detail the arrangements to be made for:
    1. Access for fire appliances.
    2. Refuse collection.
    3. Directions for emergency services.
    4. Postal delivery.
    5. Stormwater runoff control.
  5. Cycleway design shall, as a minimum, comply with the New Zealand Supplement to the Austroads Guide to Traffic Engineering Practice, Part 14: Bicycles.
  6. The minimum gradient for all roads with kerb and channel shall be 0.50% (1:200) on both sides of the road other than on transitions to super elevations.
  7. The gradient within 30m of an intersection on urban streets shall not exceed plus or minus 10% longitudinally and shall preferably be less than +/- 3% crossfall.

DS-   Rural Roads

The following shall apply:

  1. The minimum required carriageway and Road Zone width for rural roads is determined by calculating the average daily traffic volume (ADT) and then referring to DS- Table 2: Requirements for Carriageway and Road Zone Widths for Different Classifications of Rural Roads. The calculation of ADT takes account of the terrain and the predicted percentage of heavy commercial vehicles by applying factors to a formula as below:
    1. Traffic volume – shall be assessed on the following basis:
Lots of 4ha or greater in area
Lots less than 4ha in area
15 vehicle movements/day/lot
10 vehicle movements/day/lot
  1. Factors for percentage Heavy Commercial Vehicles (HCVs):



  1. Factors for types of terrain:
Cars Level 1.0 Rolling 1.0 Mountainous 1.0
Trucks Level 2.2 Rolling 5.0 Mountainous 10.0
Buses Level 2.0 Rolling 3.4 Mountainous 6.0
  1. Calculation

Multiply the traffic generation from each lot by the percentage composition for cars and HCVs and then multiply by the factor for the type of terrain.

Example: Lot Area = 20ha
Terrain is Rolling – Total vpd =15
ADT Calculation:
Total ADT


= 15 x 90% x 1.0 = 13.5
= 15 x 10% x 5.0 = 7.5
= 21.0


  1. DS- Table 2: Requirements for Carriageway and Road Zone Widths for Different Classifications of Rural Roads sets out the requirements for carriageway and Road Zone widths for different classifications of "Rural" roads.
  2. The terrain types are defined as:
    1. Level terrain – any combination of grades and horizontal and vertical alignment permitting HCVs to maintain about the same speed as cars.
    2.  Rolling terrain – any combination of grades and horizontal and vertical alignments causing HCVs to reduce their speeds substantially below those of cars, but not causing them to operate at crawl speeds for any significant distances and/or at frequent intervals.
    3. Mountainous Terrain – any combination of grades and horizontal and vertical alignments causing HCVs to operate at crawl speeds for significant distances and/or frequent intervals.
  3. Rural roads with an ADT in excess of 2,500 vpd shall be designed in accordance with the State Highway Geometric Design Manual and shall be specifically approved by Council.
  4. The gradient within 10m of an intersection on a rural road shall not exceed minus 3% or plus 5%.

Table 2: Requirements for Carriageway and Road Zone Widths for Different Classifications of Rural Roads

Classification Criteria Standards Carriagway width (m) Required for Terrain
Category Traffic Volume (ADT) Road Zone (m) Level Rolling Mountainous Maximum Length Maximum Gradient (%)
  <100 15 6.5 5.5 5.5   12.5
100 - 250 20 7.0 6.5 6.0 12.5
250 - 1000 20 8.0 7.5 7.0 12.5
>1000 20 9.0 8.5 7.5 12.5
Private way 6 lot max 6 3.0 3.0 3.0 500 with passing bay as appropriate 16.7

DS-4.5.2   Geometric Design

Drawing Ref: T405, T410, T411, T412, T413

The following shall apply:

  1. All roads shall be designed in accordance with DS-4.5.1   Widths, Lengths and Grades, Austroads Guide to Road Design and Austroads Guide to Road Safety.
  2. Design of road extensions shall take into account horizontal and vertical interface with the existing road alignment.
  3. A safety audit report may be required.  Refer to DS-4 Apx D Safety Audits and Table 1-Design Requirements for Various Road Classifications for all safety auditing requirements.

DS-   Gradients

The following shall apply:

  1. Gradients of all roads shall comply with the requirements DS-4.5.1   Widths, Lengths and Grades.
  2. In specific cases application for approval of steeper gradients may be made to Council subject to special provisions relating to safety and drainage considerations.
  3. Grades shall be as long as possible with vertical curves provided to comply with the standards quoted above.

DS-   Horizontal Curves

The following shall apply:

  1. The minimum horizontal curve radii shall be designed to reflect the intended road use and anticipated traffic speed.
  2. Horizontal curves in urban zones shall be circular with a minimum centreline radius of 80m for all industrial, collector and arterial roads. For local roads the radius may be reduced progressively as the traffic volume decreases to a minimum of 30m.
  3. Specific design shall be required where operating speeds exceed 50km/h.
  4. The need for extra carriageway widening on horizontal curves shall be assessed for both rural and urban roads as follows:
    1. Extra widening is required on curves where the radius is less than 80m. This is assessed at between 0.5m and 1.5m and the Road Zone may need to be increased accordingly.
    2. DS- Table 3: Roads with a Design Speed of 50 kph-60 kph and DS- Table 4: Rural Roads: Recommended Values for Curve Widening for 2 traffic lanes apply.

Table 3: Roads with a Design Speed of 50 kph-60 kph

Widening on Horizontal Curves
  2 Lane Carriageway Width (m)
Radius (m) 6.0 6.5 7.0 7.5 8.0 8.5
Metres Widening
<40 1.75 1.50 1.25 1.00 0.75 0.50
40-50 1.50 1.25 1.00 0.75 -.50 -
50-80 1.25 1.00 0.75 0.50 - -

Table 4: Rural Roads: Recommended Values for Curve Widening for 2 traffic lanes

Curve Radius (m) Total amount of widening (m) where normal width of 2 traffic lanes is:
6.0m 6.5m 7.0m 7.5m
30-50 2.0 1.5 1.5 1.0
50-100 1.5 1.0 1.0 0.5
100-250 1.0 1.0 0.5 -
250-750 1.0 0.5 - -
>250 0.5 - - -

DS-   Reverse Curves

The following shall apply:

  1. Reverse curves shall be separated by a length of straight road as set out in Austroads Guide to Traffic Engineering or Rural Road Design to allow a satisfactory rate of super-elevation reversal.
  2. At intersections the kerb line and cul-de-sac turning circles shall be as shown on the Standard Drawings.
  3. Specific design shall be required at major intersections and roundabouts to meet the tracking requirements as set out in New Zealand On-Road Tracking Curves RTS 18. (Road and Traffic Standards.)

DS-   Carriageway and Berm Crossfalls

The following shall apply:

  1. The standard carriageway cross-fall shall be 3% for urban/rural roads in both directions from the crown.
  2. Existing carriageway widening/steep terrain:
    1. 2% - 4% (urban).
    2. 5% (rural) from the crown coupled with a lateral shift in crown position of up to one quarter of the effective road width.
  3. Single crossfall carriageways will be permitted on local roads and private ways only subject to approval from Council.
  4. Standard berm cross-fall: 2% (minimum), 5% (maximum).
  5. Berm cross-falls >5% (i.e. in steep terrain or when widening existing carriageways), shall be considered on a specific design basis requiring approval from Council which shall take into account the future needs for pedestrians, cycling, and/or the provision of utility services.

DS-   Super-Elevation

The following shall apply:

  1. For urban roads super-elevation shall be applied to curves on all roads where the speed environment exceeds 70kph and to approved arterial roads in accordance with Austroads Urban Road Design, Guide to the Geometric Design of Major Urban Roads.
  2. For rural roads refer to the Austroads Rural Road Design Guide to the Geometric Design of Rural Roads.

DS-   Cut / Fill Batters

The following shall apply:

  1. Urban Roads
    1. Cut and fill batters for roads shall be constructed within the Road Zone with a maximum grade of 20% (1:5) starting at the road boundary. There shall be provision for forming a vehicular entrance into each lot at a gradient not steeper than 20% from the back of the footpath and allowance made for the retention of stormwater runoff in the road channel. 
    2. Where circumstances dictate a steeper grade is necessary, a geotechnical assessment of the slope shall be provided together with specific access design.
    3. Road batters for cuttings and embankments shall normally be constructed outside the Road Zone and any batters encroaching the street boundary may only be allowed only at the discretion of Council. Provided such dispensation is permitted, the face of the batter shall be protected as directed by the Council.
    4. Any retaining wall designed to support the road or footpath shall be constructed within the Road Zone and may require a building consent.
    5. Where in the opinion of Council the stability of any planned embankment is in doubt, the Consent Holder may be required to provide a stability analysis of the slope under saturated conditions.
  2. Rural Roads
    1. Rural batters for cuttings and embankments shall usually be constructed inside the Road Zone.
    2. Batters less than 750mm high shall be cut at 1:4 and shall be topsoiled and grassed.
    3. Batters 750mm high and above shall be cut at 2H:1V and shall be protected from face erosion by hydro-seeding or similar.
    4. Batters 4.5m high and above shall be assessed by a Geo-Professional.  In undertaking this check the Geo-Professional shall take into account:
      1. The type of soils present in the cutting.
      2. The degree of possible erosion and its effect on long term stability and the safety of road users and adjacent property owners.
      3. A stability check based on effective stress analyses and appropriate groundwater conditions.
    5. Stormwater disposal from cut or fill batter benches shall be by pipe, flume or other approved structure.

DS-   Intersection Design

Drawing Ref: T410, T411, T412, T413, T414, T415, T416

The following shall apply:

  1. Intersections involving Collector, Arterial Roads, Expressways or Motorways require specific design.
  2. All intersections shall be designed according with Austroads Guideline for Traffic Engineering Practice Part 5 – Intersections at Grade.
  3. The separation between any two roads intersecting a collector road or higher classification shall be a minimum distance of 150m centreline to centreline. Two minor access roads intersecting a local road shall be offset at least 60m centreline to centreline.
  4. All urban intersections shall have splitter islands to maintain lane widths.
  5. All rural intersections with an 8.0m carriageway and above shall include kerb and channel.
  6. All rural intersections with an existing or calculated ADT greater than 250vpd require splitter islands.
  7. Rural Intersections may have a minimum kerb radius of 9.0m. Specific design will be required at major intersections and roundabouts to meet the tracking curve requirements as set out in New Zealand On-Road Tracking Curves RTS 18. (Road and Traffic Standards.)
  8. Sight distance criteria at intersections as well as for stopping, overtaking, curves and obstructions shall be applied in accordance with Austroads Guide to Traffic Engineering Practice Part 5: Intersections and Part 6: Roundabouts.

DS-   Roundabouts

Drawing Ref: T421, T422

Design of roundabouts shall comply with the Austroads Guide to Traffic Engineering Practice Part 6: Roundabouts (as amended for New Zealand conditions) and NZTA Manual of Traffic Signs and Marking Part 2.

DS-   Cul-de-sac Design

Drawing Ref: T405, T421, T422

The following shall apply:

  1. The design of cul-de-sac turning areas shall be in accordance with the Standard Drawings except that for commercial and industrial areas the minimum radius shall be 15m.
  2. All urban roads shall have kerb and channel with associated stormwater collection and disposal systems provided on all cul-de-sac heads to the tangent point.
  3. For rural roads Council may require kerb and channel with associated stormwater collection and disposal systems to be provided on cul-de-sac heads where conventional shoulder/berm surface runoff is unable to be achieved to Council’s satisfaction.

DS-   Parking Bays

Drawing Ref: T450

The following shall apply:

  1. Parking bays shall be constructed and designed in accordance with AS2890.1.
  2. Parking bay pavements shall be constructed to the same structural standard as the adjacent road pavement.
  3. It is recommended that the surface of a parking bay be treated differently from that of a carriageway to differentiate its use. 
  4. A reinforced concrete dish channel constructed as shown in the Standard Drawings shall be used where a parking bay falls to the carriageway.

DS-   Provision for Bus Service

  1. Any proposed bus priority measures shall be designed in conjunction with Council and Bay of Plenty Regional Council transportation staff.
  2. Refer to Council Guideline Provision For Bus Service for design and construction information.

DS-  Secondary Flowpath in Carriageways

Secondary Flowpath within the carriage way must be designed in accordance with Austroads “Guide to Road Design Part 5a”, Table 5.2 and summarized below. 

  1. For pedestrian safety:
    ​Likelihood of pedestrians are crossing the flow path
    1.  Lower likelihood - dgVave < 0.6m2/s
    2. Higher likelihood -  dgVave < 0.4m2/s 
      Explanatory Notes:
      A higher likelihood of pedestrians crossing the overland flow path is provided where pedestrians are directed to, or most likely to cross water paths (such as marked crossings and corners of intersections)
      dg = flow depth in the channel adjacent to the kerb i.e. at the invert (m)
      Vave = average velocity of the flow (m/s)​​
  2. For vehicle safety:
    Maximum energy level of 300 mm above roadway surface for areas subject to transverse flow.

DS-4.5.3   Construction Layer Profiles

The following shall apply:

  1. In all cases the crown shall be confined to a quarter width of the lip to lip dimension with a uniform grade to the channel lip or to another point as shown on the drawings.
  2. Where the crown is required to be off-centre or the crossfall is not to be 3%, then the crown above the lip of channel, shall be specifically designed to show that the maximum and minimum crossfalls have been achieved.

DS-4.5.4   Structural Design of Pavements

The following shall apply:

  1. All roads shall be designed for structural pavements to have a minimum performance life of 25 years before major pavement reconstruction may be necessary. It is recognised that as a result of wear and tear, loading and natural occurrences, resurfacing to maintain the pavement condition may be required within the design life.

The intent of roadway pavement design shall be to achieve:

  1. A structurally sound pavement to prevent punching shear, horizontal shear, delamination and surface rutting.
  2. A finished surface stiffness that ensures that the pavement design life and surfacing performance indicators will be met.
  3. An aesthetic surface that does not produce excessive tyre noise.

Adequate attention shall be paid to the design, construction and measurement of subgrade performance together with specified unbound pavement aggregates complying with the NZTA standard specifications to ensure that the structure will provide adequate pavement strength.

  1. All new and reconstructed pavements shall be designed in accordance with Austroads pavement design parameters contained in:
    1. A Guide to the Structural Design of Road Pavements 1992 AGPT and AGRD series.
    2. Supplementary ARRB Report Number 21 – A Guide to the Design of New Pavements for Light Traffic. APT 36/06.
    3. NZTA Supplement to the Austroads Guide - November 1995.
  2. The primary design method accepted by Council for pavement design for most urban and rural applications is the California Bearing Ratio (CBR) method. Refer DS-4.5.4 Table 6: Design Processes Based on Road Type. Acceptance or not of any proposed design is made on a "project specific" basis.  
  3. The design manuals referenced in DS-4.5.4 b) define pavement depth as a function of subgrade conditions, traffic loadings (equivalent standard axles), and the properties of imported sub-base and basecourse materials. Once the subgrade CBR has been determined, the pavement overlay shall be derived from the design chart shown on DS-4 Apx B.1 General.
  4. Equivalent Standard Axles (ESAs) per lane shall be assessed on the number of lots served by the road. The design ESA’s shall include all construction traffic and all traffic movements projected over the design life of the pavement.
  5. The minimum pavement depth shall be 170mm for all cases shown in DS-4.5.4 Table 6: Design Processes Based on Road Type.
  6. For various surface types an indicative life-cycle time period (based on historical data) is shown on Table 5: Surfacing Type Lifecycles.
  7. Design of pavements by other methods is permitted but only after consultation with and acceptance by Council. Where alternative design processes are proposed, acceptance to adopt the design method shall be "project specific" and be obtained before approval, and shall include:
    1. The basis of the pavement design approach and technical references in support of its use.
    2. Commentary as to the reasons that the Austroads Guides are not considered appropriate and therefore not being used.
    3. An outline of site data collection and schedule of field laboratory testing to be undertaken as appropriate.
    4. An outline of design and construction compliance with the pavement stiffness characteristics required.
  8. The Designer shall provide test results to show that the correct assessment of the subgrade characteristics and appropriate pavement design have been made to ensure the requirements of IT-4 Transportation Network can be met.

Table 5: Surfacing Type Lifecycles

Surfacing Type Use Category - vpd (for RAMM Tables)
  1 2 3 4 5
Vehicles per day (vpd) <100 100-499 500-1,999 2,000-10,000 >10,000
  Life Cycle (years) - Historical Data
Multi Application Type          
Initial Waterproofing          
First coat seal (grade 4 or over) 2 1 1 1 1
Secondary coats          
Grade 5 seal 10 10 8 6 6
Grade 4 seal 14 12 10 10 7
Grade 3 seal 16 14 12 10 8
Grade 2 seal N/A N/A N/A 10 8
Thin Asphaltic Concrete 16 16 16 14 12
Single Application Type          
Twin Coat Grade 3/5 Seal 15 12 10 10 N/A
Concrete or clay pavers 20 (expected) 20 (expected) 20 (expected) N/A N/A

Table 6: Design Processes Based on Road Type

Road Type Design Method Reference Manual
Local road
Sub-collector (distributor)
Light industrial
CBR % method. A deflection design method based on design traffic Equivalent Standard Axles (ESA's) may be used in conjunction with the CBR method. Austroads Design of New Pavements for Light Traffic
Heavy industrial/ commercial road
arterial road
Interlayer strain analysis by CIRCLY Austroads 1962 – Structural Design of Road Pavements

DS-   Determination of Subgrade Characteristics

The following shall apply:

  1. For pavement design purposes the subgrade is defined as the block of soil present directly below the sub-base or basecourse layers to a depth of 500mm.
  2. Subgrade characteristics for pavement design are not determined until landform earthworks have been undertaken and completed. For the purposes of approval, assumed values can be applied based on judgement and experience, on the basis that confirmation tests and/or assessments are made to confirm the design when the pavement subgrade is exposed. Council shall be notified when the subgrade testing/assessments are to be made.
  3. There are 3 predominant soil types in the City area which will comprise most subgrades:
    1. Sands.
    2. Volcanic ash (being pumiceous sands, silts and clays).
    3. Peat or estuarine deposits (compressible soils).
  4. Designers must be fully conversant with the sensitive nature of the volcanic ash soils when subjected to traffic loading and shall take full account of these characteristics in designing pavement thickness.

Important factors are:

  1. The site soil/fill soil subgrade will be subjected to intensive construction traffic loading.
  2. Volcanic ash soils remould, lose shear strength and become more flexible with repeated traffic loading.
  3. Volcanic ash soils have an ability to substantially regain shear strength and stiffness where, after remoulding, they are left in an un-trafficked state. The time durations to achieve this vary according to the nature of the ash, its water content and permeability. The effect on the subgrade (which is negated in time) is due to the drainage of water used for basecourse preparation into the subgrade.
  4. Measurement of the subgrade soil characteristics shall reflect the disturbed remoulded characteristic.
  5. Having subdivided the roadway into sections which are deemed homogenous with respect to subgrade type, topography and drainage, a design subgrade CBR value shall be determined by Insitu CBR tests using the tests required by IT- 4.2.1 Subgrade Testing Carriageways.
Explanatory Note:
The Scala Penetration Test that derives CBR parameters by reference to ad-hoc relationships between these properties is not acceptable for pavement design.

DS-   Subgrade Improvement

The following shall apply:

  1. Where the Designer wishes to use stabilisation as a method of design or where the existing subgrade is of a low bearing value and the designer wishes to strengthen it, it may be advantageous to stabilise the subgrade or the sub-base.
  2. When a stabilising agent is proposed to be used the designer shall submit a range of relevant test results and calculations, including the percentage use of the stabilising agent and an indication of the likely CBR value to be achieved by the stabilisation.
  3. The minimum depth to be stabilised shall be not less than 150mm. The equivalent CBR value obtained from the stabilised soil tested in the laboratory and in situ shall be used for design to determine the overlying aggregate thickness.
  4. Alternatively, the Designer may wish to improve the subgrade by undercutting and replacement with a better quality selected material. A geotextile/geogrid may also be required to separate the subgrade from the selected layer if the subgrade is likely to contaminate it. Specific design to include the effect of the geotextile/geogrid may be used if this can be substantiated by a measured improvement in subgrade strength.
  5. The extent of areas of subgrade improvement and installation of geofabric shall be shown on the As-Built plans.

DS-4.5.5   Kerb and Channel

Drawing Ref: T420, T421, T422, T423, T424 

The following shall apply:

  1. Urban Roads
    1. Kerb and channel shall be provided on both sides of the carriageway in all urban areas.
    2. Mountable kerb is only permitted in built up areas with specific approval.
    3. The standard non-mountable kerb and channel profile shown in the Standard Drawings is required within the low speed urban environment and the mountable kerb and channel in the higher speed environment of the rural area where no pedestrians are involved.
    4. Subsoil under-channel drains shall be provided along kerb lines including medians, roundabouts and traffic control islands as shown on the Standard Drawings except where the Designer can demonstrate that they are not necessary (e.g. where the underlying soil has a high porosity or at high points in the topography).
    5. Additional subgrade drainage may be required as identified in the Development Evaluation Report and/or by the Council.
  2. Rural Roads
    1. Kerb and channel shall be required where necessary to control stormwater runoff. Generally it may be considered for construction adjoining cut and fill batters to control potential scouring of the water tables and embankments.
    2. Subsoil drains shall be installed adjoining all cut batters.

DS-4.5.6   Carriageway Surface Features

Carriageway surface features include:

  1. Roundabouts.
  2. Traffic Calming.

DS-   Roundabouts

Design of roundabouts shall comply with the Austroads Guide to Traffic Engineering Practice Part 6: Roundabouts as amended for New Zealand conditions as well as the New Zealand Manual of Traffic Signs and Markings Part 2 (MOTSAM).

DS-   Traffic Calming

Drawing Ref: T422

The following shall apply:

  1. In residential streets traffic calming measures may be required to ensure the design speed regime cannot be significantly exceeded.
  2. Traffic calming where used shall be based on relevant current practice but may incorporate such measures as providing horizontal bends of significant deviation (45° or more) at distances of not more than 100m between tangent points, provision of speed humps, traffic islands, raised pedestrian crossings, lane deflections, local lane narrowing etc.
  3. These measures shall conform with the guidelines contained in NZTA Road and Traffic Standards RTS 15.
  4. Where a street forms, or may form, part of a designated bus route, vertical traffic calming mechanisms such as speed humps, raised platforms or similar devices are discouraged. Specifically designed measures such as speed cushions or similar shall be discussed with Council approval is given.
  5. The impact on the operation of emergency vehicles shall also be a consideration for any traffic calming device.

DS-4.5.7   Sumps

Drawing Ref: T425, T426, T427

The following shall apply:

  1. Sumps shall be located as follows:
    1. On roads having a carriageway up to and including 11m wide and a maximum channel run of 100m.
    2. On all roads with a carriageway greater than 11m wide and a maximum channel run of 80m.
    3. On the high side of intersections located at the kerb line tangent point.
    4. At changes of gradient or direction in the channel where there could be a tendency for water to leave the channel.
    5. A double sump shall be installed to minimise the risk of ponding at cul-de-sac heads where there is a low point and at the lowest point in a sag vertical curve where the gradient exceeds 12%.
    6. Where longitudinal gradients of a carriageway exceed 12%, sumps shall be located at a maximum of 80m intervals for carriageways up to and including 10m wide and 65m intervals on wider carriageways and in all cases shall be a high capacity sump.
    7. Sumps shall not be located at the apex of a bend.
  2. Where kerb and channel is utilised, sumps shall be located to ensure safe passage for cyclists, motorized traffic and pedestrians. This may include recessing the sump or selecting a sump type that does not affect the surface of the carriageway or the alignment of the footpath.
  3. Roads without kerb and channel shall have a specifically designed stormwater catchment system subject to Council approval.
  4. Sumps shall be constructed to ensure optimal functionality e.g sump grates and backdrops match the kerb and carriageway gradients.

Sump designers shall also refer to DS-5.8.2 Sumps

DS-4.5.8   Carriageway Surfacing

Carriageways shall be surfaced with bituminous seal unless otherwise approved by Council.

DS-   Hot-laid Asphaltic Concrete (asphalt)

The following shall apply:

  1. All arterial and collector roads, including cul-de-sac heads, turning areas, roundabouts, approaches and industrial intersections shall be surfaced with asphaltic concrete unless otherwise approved by Council.
  2. As asphaltic concrete is not in itself completely waterproof, a first coat seal or similar shall be required to provide an initial waterproofing layer.
  3. When a membrane seal is used, a minimum of 1.0 L/m² of residual penetration grade bitumen shall be required. The manufacturers recommended time shall elapse between the first coat seal and the laying of asphaltic concrete to ensure adequate curing of the binder.
  4. When using NZTA Specification M10 compliant mixes on roads with an ADT greater than 100vpd, NZTA guidelines on skid resistance and surface texture shall be incorporated in the mix design.
  5. Non-structural asphalt layers are not considered to be part of the structural pavement design.

DS-   Two Coat Seal (First Coat with Wet Locking Coat)

The following shall apply:

  1. Except where otherwise approved by Council, basic carriageway surfacing shall be a first coat chip seal, followed by a second coat chip seal after 12 months.
  2. Generally, the first coat shall use Grade 3 chip and the second coat shall use a chip size between Grade 4 and Grade 5 as appropriate to the location. 
  3. A two coat seal as a first coat does not remove the need for a second coat seal.

Refer to the NZTA Manual Chipsealing in New Zealand for further chipseal design parameters.

DS-   Interlocking Concrete Block Paving

In general, block paving shall not be permitted as a carriageway surfacing material unless otherwise approved by Council.

Definitions in this section


Bay of Plenty Regional Council

City plan

Consent holder






Development works approval






Local roads


Low impact design





Private way

Resource consent


Secondary flowpath

Standard drawings





Urban area

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