At what sort of speeds is this available?
The British driving exam and driving code says a distance of 6 car lengths is appropriate for ~50km/h (30mph), in dry weather. Anything faster, wetter or at night needs more distance.
In Germany, the rule of thumb (based on reaction times) that's also taught in driving school for normal weather and road conditions during the day is "Halber Tacho" [1], i.e. at least half your speed (in km/h) as safety distance (in meters).
Example: driving at 100km/h the minimum safety distance to have is 50m, the distance at which the "Leitpfosten" [2] ("delineator"?) are usually fixed along the roadside.
[1]: https://de.wikipedia.org/wiki/Sicherheitsabstand#Ermittlung_... , translated: https://de-m-wikipedia-org.translate.goog/wiki/Sicherheitsab...
[2]: https://de.wikipedia.org/wiki/Leitpfosten , translated: https://de-m-wikipedia-org.translate.goog/wiki/Leitpfosten?_...
I had to look up the name of the Leitpfosten in English, "distance marker posts". They're at 100m intervals on motorways (I knew that bit).
A different style is called "hazard markers" or "hazard marker posts" and used only where appropriate. There are also snow poles on some roads, mostly in Scotland. I can't see any specified distance for either type.
[1] §126 of https://www.highwaycodeuk.co.uk/control-of-the-vehicle.html
(The odd mixture of units is consistent with normal British usage, as is the construction of the road in metres but the signing of it in "yards" (often actually metres).)