motorway roadworks - purple tubing?

[hungry horace]

spending the hours pounding the motorway network, i often see purple tubing adorning the central reservation within roadwork sections. (most recently m1 j28-32 and j39-42). there is miles of it! at times this is broken / not joined fully, and there appears to be 5-6 strands of cabling in there.

anyone in-the-know enlighten me as to what this is, what it is for - data / power??? it never seems to distribute anywhere, only from end-to-end, often miles apart.