Decals
To spawn a decal (lane marking, crack in asphalt, dirt etc.) you can use our specialized version of the DecalComponent named the PathTemplateDecalComponent. It has extra properties related to the spawning (randomization, extra copies etc.). Decals can be also spawned by as the PathTemplateStaticMeshComponent or PathTemplateSplineMeshComponent, if you require converting them to HISMs, or they need to bend with a Path.
REMAINDER
If the decal doesn't render correctly, make sure it is rotated correctly. Try rotating it 90 deg. in various directions.