Delineator posts come in a variety of shapes and colours and also have a variety of potential uses. They can also be used as temporary (as described in TCD manual Part 8) or permanent delineation devices and vary by position on the road such as, but not limited to, the centre, lane lines and merge points. These devices are often used in areas where it can be demonstrated through crash records or erratic traffic manoeuvres that the existing pavement markings and raised pavement markers are not adequate. The use of delineator posts also reflects a desire to improve perceived safety and they may be used where cyclists regularly feel unsafe (eg due to being passed closely). When considering the use of delineator posts in relation to cycling facilities and cyclists there are a number of specific issues to consider. Details of these issues and how to resolve them are presented in the Cycling Network Guidance: Choice of separator or protection.
TCD manual Part 8
Cycling Network Guidance: Choice of separator or protection.
In the TCD manual, the term “delineator posts” does not include edge marker posts (EMPs); for further information on the use of edge marker posts, refer to edge marker posts.
Edge marker posts
Delineator posts may be used to provide:
- temporary traffic management at roadwork sites (refer to TCD manual Part 8 Section B – Equipment);
TCD manual Part 8 Section B – Equipment
- lane delineation in order to separate vehicles travelling in the same direction. The posts are intended to discourage lateral movements between lanes where this might be hazardous or in order to offer vulnerable road users (eg cyclists) a degree of safety;
- enhanced lane separation that can be used to highlight the location of the road centre-line or the presence of features that separate vehicles travelling in the opposite direction (eg supplement dividing barriers, painted islands, etc). The posts are intended to discourage vehicle movements across the centre-line at potentially hazardous locations;
- a means to control and restrict vehicle movement to the appropriate position on the road, for example at merge areas in higher speed environments at a seagull or similar island arrangement. Posts in this situation are being used to manage road user behaviour where frequent and hazardous encroachments might otherwise occur; and
- delineation for a feature in the road that is not visible due to vertical topography, for example to provide additional warning of a painted island, barrier or median strip where visibility is limited by vertical curvature on a crest.
In exceptional circumstances, delineator posts may be used permanently to aid delineation. Examples include narrow multilane bridges, where installing a raised median is not possible, and to prevent right turns where a raised median is not possible. Careful consideration should then be given to whether a road safety barrier may be more appropriate in these situations.
Their use should also be limited to the following:
- Locations where the 85th percentile approach speed is less than 85km/h; however, they may be used in higher speed areas where engineering judgement dictates it may be necessary for safety purposes (eg to provide advance warning of traffic islands where there is very limited approach sight distance).
- The maximum device height should be 1000mm.
- Delineator posts should not be installed on two-way roadways less than 7m in width and / or where the lane width (exclusive of the central delineator posts) is less than 3.5m.
- Delineator posts should not be installed near well-defined areas of pedestrian activity or where they are likely to be hazardous to motorcycle and bicycle riders.
There are numerous aspects to consider in relation to the use of delineator posts. These include, but are not limited to:
- post cost;
- maintenance (eg cost of, replacement of posts – including TTM and replacement methodology, cleaning, long-life product, etc);
- perceived safety benefit and perceived safety dis-benefit;
- access permeability through the delineator post installation;
- mounting shape / fixing system / surface on which the posts will be installed;
- colour (eg what colour, will the colour fade);
- height of the post;
- shy lines and adjacent facility or lane width;
- visual impact (eg streetscape);
- manufacturing (eg ease of production, cost, shape, material type); and
- durability (eg UV resistance).
