Edgelines

Edgelines delineate the edge of the traffic lane on the far left and far right of a roadway and, in situations where the shoulder is sealed, edgelines separate the shoulder from the traffic lane. In these situations, the provision of edgelines not only enhances road safety but can also reduce wear and maintenance of the shoulder. In addition, they provide a useful guide to motorists in inclement conditions.

There are several types of edgelines currently used, such as standard white markings with audio tactile properties and RRPMs placed alongside or overlapping standard markings.

Legislation

The TCD rule (clause 7.5) specifies that:

If a road controlling authority consider it desirable, it may mark an edgeline at or near the far left or far right side of the roadway to define an area of roadway for use by vehicles.

An edgeline must be marked or defined by one or more of the following:

(a) a broken or continuous white line; or

(b) a kerb.

Application

Edgelines are used to:

• delineate the edge of a traffic lane;
• separate a sealed shoulder from the traffic lane;
• provide useful guidance to motorists at night and during inclement weather; and
• laterally position vehicles on wide roads, particularly in urban areas.

The marking of edgelines is recommended in the following situations.

Rural state highways

Edgelines should be marked on two-lane rural state highways where one or more of the following conditions apply:

• the seal width is 7.4m or more; or
• the seal width is 6.6m or more and the AADT exceeds 750vpd; or
• special conditions such as difficult terrain, fog, mist or steam prevail.

Other rural roads

Edgelines should be marked on sealed local rural roads as summarised in Table 2‑20.

Table 2‑20: Rural road edgelines

Table 2‑20 note:

• Isolated sections of road may require edgelines similar where road edge maintenance is a problem.

Urban roads

Edgelines should be continuous and marked parallel to the road centre-line except at intersections and lane drop/gain situations. Marking requirements are outlined in Table 2‑21.

Table 2‑21: Urban road edgelines

Edgelines should be marked as shown in Table 2‑22.

Typical layouts for standard markings

Where they are used at intersections, refer to TCD manual Part 4.

Table 2‑22: Standard marking requirements for edgelines

Refer to the marker layouts section for specific requirements for raised pavement markers at edgelines.

Marker layouts

Wide edgelines

Wide edgelines should be reserved for routes and locations where the crash history indicates a specific problem with the definition of the lane edge or there is a problem with standard delineation. Consideration should also be given to the use of red Category G Type 1 one-way RRPMs (refer to marker layouts section).

Marker layouts

Wide edgelines are either 150mm or 200mm wide and can be used in both urban and rural areas. Requirements and recommendations on their use are outlined in Table 2‑23.

Table 2‑23: Standard marking requirements for wide edgelines

Edgelines at abrupt changes in lane width

Special consideration should be given to the marking of edgelines where there are otherwise abrupt changes in lane width, for example at the transition between a wide kerbed urban/semi-rural road and a narrower unkerbed rural road. These transition markings are recommended for all such situations irrespective of road width or traffic volume, however, transition markings on short no-exit rural roads are not usually necessary.

Where such width changes arise, the taper length between one width and the other shall be calculated using the formula below:

These markings are not to be used at the approaches to one-lane bridges or short sections of one-lane road.