Flush medians

A flush median (also referred to as a painted or hatched median) is an area to the centre of the roadway that has been marked to restrict through traffic movements to the adjacent lanes and / or typically as part of a right turn lane.

A flush median can be used in both rural and urban areas. Examples of these are shown in:

• Figure 2‑3
• Figure 2‑4

Legislation

The TCD rule (clause 7.4) states that:

A road controlling authority may mark a flush median on a roadway if it is considered that there would be safety and efficiency benefits in:

• separating turning traffic and through traffic; or
• providing pedestrians with place to pause while crossing a road; or
• providing greater separation between traffic travelling in opposite directions; or
• limiting the lane widths to reduce traffic speed.

A flush median must comprise an area marked by white diagonal lines that are painted along the middle of the roadway and are bounded by approximately parallel, longitudinal white lines.

Refer to Figure 2‑5 for flush median layout diagrams

Application

Flush medians are generally not used in rural areas as there are less accesses and therefore, there is less need for turning protection and historically they have been used illegally to overtake other vehicles. Wide centre-lines have been increasingly used in some places instead of flush medians to provide better head on protection than a standard centre-line.

Wide centre-lines

Where in the special circumstances, flush medians are used in rural areas to accommodate turning movements they should be marked as specified in Table 2‑8.

Table 2‑8

In addition, if flush medians are used as an area from which to turn, sight distance needs to be considered.

Further information on application and safety benefits of using flush median on rural roads can be found within the High-risk rural roads guide.

High-risk rural roads guide

Figure 2‑3: Example of a rural flush median

Figure 2‑4: Example of an urban flush median

Flush medians should be marked as specified in Table 2‑8. Flush medians must be marked with diagonal lines that join directly into the border line, ie with no gap.

Table 2‑8: Flush median road markings on rural and urban roads 

Table 2-8 notes:

1. Care must be taken when using wider flush medians in rural areas as these can sometimes be used for overtaking manoeuvres.

To give pedestrians an extra measure of safety, solid pedestrian refuges should be located at points where there are higher pedestrian volumes if the width of the flush median permits this. Further information on pedestrian crossings within flush medians is provided in the flush medians section.

Flush medians

Diagonal line spacing for flush medians

The recommended ranges for bar spacing on flush medians for both urban and rural roads are listed in Table 2‑9.

Table 2‑9: Diagonal line spacing

End treatment tapers

Border lines on flush medians should be tapered as indicated by the following formulae and shown in Figure 2‑5.

The approach and departure tapers length (L) are based on a sideways movement of approximately 0.6 m/s.

Figure 2-5: Flush median markings

(a) Standard marking details

(b) End treatment details

View larger image [JPG, 1.6 MB]

Also refer to features, structures and hazards on, beside or above the roadway for features and structures in the road for additional information on median islands.

Features, structures and hazards on, beside or above the roadway

Night-time visibility and lighting

Flush medians need to be seen by drivers and pedestrians in adverse light or weather conditions. There are various ways of achieving this:

• appropriate street lighting;
• use of long-life materials; including but not limited to thermo-plastic, cold applied plastic or pliant polymer;
• use of retroreflective raised pavement markers (RRPMs); or
• a combination of the above.

Further consideration should be given to the type of surface they are applied to, for instance:

• a well-lit smooth asphalt road with a retroreflective flush median may still have glare from headlights on a wet night; in this case the use of RRPMs is recommended; and
• a well-lit course chip seal road with long-life markings may well have adequate visual impact, even on a wet night.

Retroreflective raised pavement markers

The placement of retroreflective raised pavement markers (RRPMs) on urban flush medians is optional; however, RRPMs should be used on flush medians provided on state highways. RRPMs, if used, should be as shown in Figure 2‑6 and as defined below:
Figure 2‑6

• only white two-way RRPMs should be used on flush medians;
• the minimum spacing of RRPMs on median border lines is 10m;
• the minimum spacing of RRPMs on median diagonal lines is 20m;
• where the bar spacing is less than 10m, central RRPMs should be located on every third diagonal line. The border line RRPMs should be located midway between each third bar; and
• RRPMs should be laid at least 50mm clear of an adjacent paint or long-life road markings.

Addition information can be found in the raised pavement markers section

Raised pavement markers

Figure 2-6: Flush median retroreflective raised pavement marker arrangements 

(a) RRPM arrangement for medians 1.0m to 2.4m in width

View larger image [JPG, 422 KB]

 

(c) RRPM arrangement for medians with bar spacing < 10m

Pedestrian crossing facilities within flush median

It is desirable to minimise the number of pedestrians crossing on sections of road with flush medians without dedicated pedestrian crossing facilities. To give pedestrians an extra measure of safety, solid pedestrian refuges should be located at points where there are pedestrian desire lines, if the width of the flush median permits this.

Refuges are especially necessary where pedestrian usage is high, and at pedestrian crossings. Where pedestrian usage is spread along the median, refuges should be constructed approximately every 400m. Refuges should be installed at points of good visibility and where they can be well-lit. They also reinforce the prohibition on overtaking on flush medians, but as with any solid object in the roadway, refuges can be a hazard to errant vehicles if not correctly delineated. Pedestrian refuge details within a flush median are provided in Figure 2‑7.

Figure 2‑7

For pedestrian refuges:

• pram crossings or gaps should be designed/installed that ensures pedestrians face oncoming traffic when standing on the refuge;
• keep left signs should be placed on the end of the island;
• kerbs/islands should be painted or delineated (Refer to clause 7.7(2) of the TCD Rule);
• lighting should be provided to highlight the location of the refuge if street lighting for illuminating the roadway does not also adequately illuminate the refuge; and
• ensure that vegetation or other road furniture does not obstruct visibility to pedestrian refuge features.

Where pedestrian crossings (zebra) are marked:

• a raised pedestrian refuge similar to that shown in Figure 2‑7 should be installed in the flush median to divide the crossing into two sections (also see Figure 7‑12);
  Figure 2‑7
  Figure 7‑12
  and
• allow a 300mm (min.) gap between the outside of the edgeline and the central island. Refer to Figure 2‑7 for marking flush medians around pedestrian refuges and other central islands.

Further information on pedestrian refuges can be found within the:

• Pedestrian and Planning Design Guide
• Roads and Traffic Standard 14: Blind and vision-impaired pedestrians
• Pedestrian refuge islands

Figure 2-7: Pedestrian refuge details

 

View larger image [JPG, 517 KB]