An optical signaling apparatus for use in highways or roadways (2), particularly in low visibility conditions, wherein a roadway (2) comprises at least one traffic bearing surface (S) with at least one edgeline (3). The apparatus comprises light-emitting means (4) for emitting at least one laser beam (5) and support means (6) designed to be arranged along the roadway (2) for supporting the light-emitting means (4). The apparatus also includes optical means (7) arranged along the roadway (2) for interacting with the beam (5) in such a manner as to selectively conform and project it either in a first direction (D.sub.1) which is incident on at least one edgeline (3) to interact therewith, or in a second direction (D.sub.2) substantially parallel to the traffic bearing surface (S) to define a substantially continuous optical path that can be viewed by the users, or even in both such directions (D.sub.1, D.sub.2).