They are placed in order to draw the attention of those who use the road for dangers that exist in the road.

The diamensions of this signs (side of triangle) are reported at lines in sizes 0.60m, 0.90m, and 1,20m that are selecteted propotionally with the use of signs.

Reflectivity Demands of Warning Traffic Signs according with the Road System to which they apply [Freeway (FR), National Road (NR), or Trunk Road (TR),] the place of the Sign, and the type of retroreflective membranes (I, II, III) are as follows:

Α. Sign Bridge: FR και NR: Membrane type ΙΙΙ

Β. Right position : FR – Membrane ΙΙ or ΙΙΙ, NR : Membrane ΙΙ, TR : Membrane Ι or ΙΙ

Γ. Left position: FR – Μεμβράνη ΙΙ or ΙΙΙ, NR : Membrane ΙΙ or ΙΙΙ, TR : Membrane ΙΙ or ΙΙΙ

Signs Κ-1α^, Κ-1δ, Κ-2δ, Κ-16, Κ-24 and Κ-31 untill Κ-37, due to their crucial importance in terms of improving the road safety, have necessarily to be constructed with membrane of at least type ΙΙ.