Chapter F8 Renewal of roads

F8.7 W/C 231: Associated improvements

Definition: work category 231

Associated improvements

This work category provides for:

• minor drainage and seal width improvements carried out in conjunction with road renewals
• widening of existing seal, where this is the least cost maintenance treatment
• installation of new minor traffic management equipment and facilities.

The cost of drainage and seal width improvements carried out in conjunction with renewal work must not exceed 20 percent of the cost of the basic road renewal work.

Examples of qualifying activities

Examples of qualifying activities include:

• installation of culverts (having a cross-sectional area less than 3.4 square metres), water channels, subsoil drainage, or kerb and channel, where this is shown to be necessary:
  • to protect adjacent property from run-off from the road surface
  • to protect the pavement
• extensions to territorial authority drainage systems in built-up areas, where such improved drainage is necessary for the protection of the road - costs should generally be apportioned according to the respective volumes of runoff from contributing areas of roadway and other land
• increases to seal width to overcome maintenance problems, up to the seal width accepted by the NZTA for the traffic mix and volume on that section of road
• installation of new signs and traffic management equipment and facilities, or upgrading these to the current standard, up to a limit of $10,000.

Reference: For detail about signs and traffic management equipment, see Chapter F13 Traffic systems and road safety.

Exclusions: work category 231

This work category excludes:

• extensions to territorial authority drainage systems in excess of the above qualifying activities - these are not eligible for funding assistance
• other proposed work in excess of the above qualifying activities, such as geometric improvements or seal widening for safety reasons - these are funded under the following work categories, unless specifically approved by the NZTA:
  • 341: minor improvements
  • 321: new traffic management facilities
  • 324: road reconstruction.

Evaluation: work category 231

RCAs must be able to show that provision of the improvement in conjunction with the renewal work is necessary and economically efficient.

The RCA must undertake economic efficiency evaluations for the following activities and make copies of the evaluations available as requested by the NZTA:

• individual seal widening projects
• new drainage facilities, such as culverts, water channels and kerb and channel
• new kerb and channel project evaluations.

These projects must be the long-term, least-cost option for the RCA, calculated in terms of present value (PV).

References:

• For detail on overwidth carriageways, see section F10.3.
• A simplified economic efficiency procedure is provided for seal widening in the Economic evaluation manual, volume 1 – see SP1.

Information for audit

The cost of drainage and seal width improvements carried out in conjunction with renewal work must not exceed 20 percent of the cost of the basic road renewal work. RCAs must be able to show that provision of the improvement in conjunction with the renewal work is necessary and economically prudent.

Details of net maintenance savings calculations for the following activities must be held by the RCA for audit purposes:

• individual seal widening projects
• new drainage facilities, such as culverts, water channels and kerb and channel
• new kerb and channel project evaluations.

These projects must be the long-term, least-cost option for the RCA, calculated in terms of present value (PV).

References:

• For detail on overwidth carriageways, see section F10.3.
• A simplified evaluation method is provided in the Economic evaluation manual, volume 1.