How many delineator posts does one kilometre of road need?
Short answer
There is no single number: the geometry of the road sets the spacing. Sparse on straights, tight on bends, with one rule — the driver should never lose one post before seeing the next.
Spacing follows the table in the authority’s specification, and the input to that table is the curve radius. As the radius tightens the spacing shortens, because the line the posts form has to show the driver where the bend goes.
So the answer to “how many per kilometre” lives in the route itself. On a straight section the count is low; on a mountain road it multiplies. Before committing to an order quantity, the curve schedule of the route should be worked out.
Send us the route length, the number of bends and the authority’s spacing table if you have one. We work out the quantity and the container plan that goes with it. With 2,500 pieces to a pallet, the count decides the freight directly.
Doing the sum before ordering costs less than running short on site. The straight and curved sections are measured separately; each length is DIVIDED by the spacing for that section, one starting post is added per section, and the totals are summed (doubled where both sides are lined). Junctions, bridge approaches and shoulder narrowings take extra posts.
Do not neglect a spare allowance. A share is lost in the first year to impact, ploughing and excavation. In practice a small spare stock is bought with the order. Spares from the same batch match the site exactly in colour and reflective class.
The second half of the spacing decision is height. At the same interval a short post disappears sooner while a tall one reads from further away. Spacing and height are therefore decided together, and an order placed on spacing alone is usually placed twice.
Four headings belong in the specification: section lengths, spacing per section, height above ground and reflective class. Given those four the count follows without argument and quotations become comparable.
The commonest mistake is writing a single spacing figure into the specification. On a route given one interval the bends end up sparse and the straights unnecessarily dense, which harms both safety and budget.
The question to ask a supplier is not the count but the method. A buyer who asks how the count was derived can compare quotations. One who asks only for a total is placing figures built on different assumptions side by side.
At order time the count directly sets the pallet plan and the container number. Freight therefore cannot be calculated before the count is fixed. The quotation gives count, pallets and containers together so the three confirm each other.
The installation plan rests on the same calculation. Once you know how many posts a crew drives in a day, the total converts directly into working time. You can then say in advance how long the road stays closed.
This page does not replace the authority’s own specification. In a public tender the spacing is usually fixed by that standard. The calculation here applies where no specification exists or where it leaves the choice open.
