Part 3 – Road Works

3.6    Road, Carriageway and Formation Widths

3.6.1    Road Width

The road width is to provide for:

• Carriageway.
• Parking.
• Cycling.
• Footpaths.
• Berms.
• Services.
• Traffic facilities.
• Landscaping.
• Road furniture.

Minimum road widths are scheduled in Table 3.1.

Preservation, or capitalisation, of some natural feature of a landscape or existing specimen trees may dictate an irregular shaped road width. 

Certain carriageway and berm geometrics may require that the road width be increased, usually locally. 

Adequate width of road reserve is important and is normally 20 m. Additional width is likely to be required where earthworks are extensive.  A minimum clearance of 3 m is desirable between the road reserve boundary and tops of cuttings or toes of embankments.

In rural and rural residential areas fences, if constructed, shall be placed on boundary lines unless written permission is received to do otherwise.

3.6.2    Carriageway Width

Two lanes for moving traffic shall be provided on all roads except where a device is used for traffic control or there is a shared environment (as defined in Table 3.1).

The minimum lane width for moving traffic is 3.0 m, and this should be increased to 3.5 m where the traffic function is dominant.   Where there is significant cycle traffic on high volume collector roads, the lane width should be increased and in some cases a marked cycle lane should be provided.

In residential areas, the carriageway may be split into separate one-way lanes for aesthetic or landscaping reasons or to suit ground levels on steep terrain, whilst still retaining adequate manoeuvrability and property access. 

Carriageway widths shall be not less than those shown in Table 3.1, except for “local roads” narrower widths may be appropriate for special conditions and designs for these shall be based on actual vehicle and turning dimensions.

Where topography or other considerations make carriageway and berm widths technically difficult and/or uneconomical, the developer may apply for a Variation to allow them to be reduced providing that there is no loss of functionality.

3.6.3    Formation Width

Formation width shall be sufficient to contain the functions described in 3.3.1 above.  Where topography permits, the formation width should extend beyond the road carriageway by 500 mm, with batters providing a smooth transition to the adjacent building lot grades. 

Where structures retaining private lots are required, these shall be fully located on the lot, not on the road.