Street lighting policy

Introduction | Appendix 1 | Appendix 2 | Appendix 3

Appendix 3 - Summary of tree policy

This report was commissioned to examine the issues of providing adequate lighting to roads, when trees are present and may cause undesirable shadowing. Also considered are ways in which new roading installations can be designed to mitigate these issues.

The results of this study have come up with the following solutions:

Where trees are existing

• For mature tree-lined roads, if single sided and of narrow nature, poles need to be located on the road side opposite the trees. If there are trees on both road sides, lighting columns on each side may be required within the minimum of 700mm of the kerb and having long outreach arms and located midway between trees. Careful pruning may be necessary to allow the light to pass under the tree canopy to the road. Consultation with the power and telecommunications utilities is required if there is overhead reticulation.
• Mature trees, where there are existing overhead, power lines will require long outreach brackets from the existing power poles with lighting columns supplementing from the other side of the road.
• Poles should be placed equidistant and at least 5m from the centre of any tree. Trees should not be planted where root structure can interfere with underground lighting cabling or other underground services unless tree pits are used to confine the root structure.

For new roading installations

• Where there are areas of new planting, consideration should always be given first to the potential impact of shadows from road lighting for safety reasons when selecting the positioning and the species of trees.
• In new subdivisions lighting column positions must be determined to conform to the Auckland City road lighting requirements at the onset and these positions fixed. The subdivider often installs these and it may be necessary to more closely specify what is acceptable. Only then should the trees be located by the Auckland City arborists and planted to a minimum number and size to create the future daytime aesthetics and to be within the minimum distance requirements of the lighting columns.

There is no simple single solution applicable for all roads or streets, which already have existing trees, but there should be a high level of coordination between the trees and the placement of lighting columns to provide an acceptable urban landscape.