Edge marker posts

This section discusses the use of edge marker posts (EMPs) on straights. For use on curves refer to the treatment of curves. 

Treatment of curves

General

Edge marker posts (EMPs) are used on rural roads to delineate the alignment of the road ahead, especially horizontal and vertical curves. Edge marker posts are typically fitted with retroreflective devices that form a primary aid for night-time driving. Edge marker posts provide useful guidance for drivers but are not a substitute for standard warning signs.

Edge marker posts should be installed on rural roads with consideration given to sealed versus unsealed and varying volumes as recommended in Table 2‑25.

Table 2‑25

Edge marker posts:

• must conform with the requirements in Schedule 1 of the TCD Rule; and
• for consistency, are required to comply with Specification M14: edge marker posts;
  Specification M14: edge marker posts
  and
• should be installed on all rural state highways, and higher volume rural local authority roads; and
• may be installed on lower volume rural local authority roads.

Edge marker post retroreflective strips on the left-hand side of the road must be white; and on the right-hand side of the road must be yellow.

Post and retroreflector specification

Refer to the Specification M14: edge marker posts for material, assembly, and dimension specifications for edge marker posts.

Specification M14: edge marker posts

Retroreflective strips must only be attached to properly prepared posts. The retroreflective strips should not be attached to poles, fence posts, signposts, trees, abutments or the like, as doing so would destroy the desirable systematic spacing intended. However, post spacing may be adjusted by up to 20% to clear driveways, side roads or other obstructions. For illustrations of edge marker post details refer to Figure 2‑13.

Figure 2‑13: Details of edge marker posts and retroreflective strips

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Location and spacing

Edge marker posts should be placed to produce a smooth flowing pattern of delineation that defines the edge of the trafficable portion of the roadway. Posts should be placed at a uniform lateral distance no more than 3m from the edge of the adjacent traffic lane. Where there are no shoulders, a minimum lateral clearance of 1.2m to the edge of the adjacent traffic lane should be provided where practicable.

Edge marker posts should be placed vertically with the top of the post 900mm above the edge of the adjacent traffic lane. This dimension should be increased when markers are attached behind a steel ribbon guardrail such that the full length of the retroreflective strip is clearly visible above it. The recommended requirements for installation of edge marker posts on rural roads and spacings regardless of volume are provided in Table 2‑25. Refer to the edge marker posts for installation of EMPs on curves.

Edge marker posts

Table 2‑25: Recommended requirements for the installation of edge marker posts on rural roads

Circumstances may exist where the installation of EMPs to a higher standard than described in Table 2‑25 is desirable; these include:

• where there are frequent and / or sub-standard horizontal and / or vertical curves;
• over sections where the crash record indicates a need;
• to maintain continuity on a route or with an adjacent road;
• through areas commonly subject to fog, mist or steam;
• through areas commonly subject to heavy rainfall (greater than 1,000mm annual rainfall);
• where there are heavy night traffic flows; and
• where there are heavy tourist traffic flows.

However, the installation of EMPs along the entire route is not normally necessary for roads carrying less than 500vpd.

Table 2‑26: Edge marker post spacing table

Table 2‑26 note:

• Refer to Figure 2‑13.

Passing lanes

The general spacing of EMPs on straights is provided in Table 2‑26. Where passing lanes are marked, the spacing of posts adjacent to the merge taper should be 20m.