For the purposes of this manual, the term “road safety barrier” includes, but is not necessarily limited to, W-section and Thrie-beam guardrails, concrete barriers such as “New Jersey” or “Tric Block” barriers, and wire rope safety barriers.
At sites where there is a history of loss of control crashes resulting in a collision with roadside hazards (or pedestrians), the protection of the road user is necessary and could be addressed by some form of road safety barrier.
Combining barriers and delineation can, on occasion, lead to unintended adverse outcomes in regard to the messages sent to drivers about the road alignment ahead. This is particularly important in regard to night-time delineation. Mounting edge marker posts (EMPs) on top of barrier system posts results in variation in height of the retroreflective markings which in turn can lead to misinformation about the route ahead when viewed during hours of darkness.
The following recommended practice aims to address installation practices, minimise the risk of misguiding road users and ensure a consistent message is given to all.
Recommended practice for delineation of road safety barriers on shoulders is provided below:
- Primary delineation comprising correctly marked and spaced edge marker posts (EMPs) complying with the requirements in the edge marker posts should be installed immediately in front of flexible (wire rope safety barrier), semi-rigid (W-section and Thrie-beam) and rigid (concrete) barrier systems, not behind or on top thereof.
Edge marker posts
- As an alternative to EMPs as primary delineation, red retroreflective raised pavement markers (red RRPMs) may be used immediately behind the left-hand edgeline in accordance with the guidance provided in the raised pavement markers.
Raised pavement markers
- Modified EMPs attached to barrier systems should not be used unless the mounting method has been accepted by the Lead Safety Advisor (Roads and Roadsides).
- Wire rope safety barrier (WRSB) installed on the left-hand shoulder should have secondary white retroreflective markers at 15m centres along its length, or at the closest value to this for the system of post spacing used. The markers should be positioned on the approach face of the posts within 10mm of the top of the posts. Delineation is enhanced when the posts are powder-coated white.
- Secondary yellow retroreflective markers may only be used on the right-hand shoulder where Type C edge marker posts (Figure 2‑13) are adjacent to the WRSB.
Figure 2-13
- Secondary delineation retroreflectors on WRSB posts should not exceed 4000mm2 each.
Table 2‑27: Road safety barrier retroreflector specifications for the edge of the road
| Size of retroreflectors |
Colour of retroreflectors |
Spacing of retroreflectors;
refer note 1 |
| Left |
Right |
| 4000mm2 (maximum) |
White |
Yellow |
15m |
Table 2‑27 note:
- For WRSB, use the closest value to this for the system post spacing used.
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