post holes 17 and are received therein as shown in fig1 the backing portion 24 is formed adjacent its side edges with thickened portions 31 and these have a series of holes 32 in which lugs 34 on the locking plate 25 are received if desired an adhesive can be used to prevent removal of the locking plate with the locking plate in position the delineator cannot be removed from the support post and it cannot be moved up or down on the post due to the engagement of the lugs 30 in the holes 17 fig3 and 4 illustrate alternative ways of connecting the locking plate to the delineator backing portion in fig3 locking plate 25a is provided with a shouldered lug 34a that is inserted in a correspondingly shouldered hole 32a in the backing portion 24a to lock the parts together the material of the parts being sufficiently compressible and resilient to allow the insertion of the lug in fig4 the locking plate 25b is provided with an edge flange 35 having on its inside surface a bead 36 that snaps into a corresponding groove 37 in the backing portion 24b fig5 and 6 illustrate a modified form of the invention wherein the delineator generally indicated at 40 has an arcuate configuration in the horizontal plane only whereby it has an essentially semi cylindrical shape as best shown in fig5 other than as to its shape the delineator 40 is constructed like delineator 15 and comprises an outer light reflecting or lens portion 41 an inner backing portion 42 and a.