Assertion: lamp's light | /r/HasProperty | aid
Facets:
value: to navigation
type: PURPOSE
Source sentences:
text: A modest steady light at the intersection of two roads is an aid to navigation because it helps a driver see the location of a side road as they come closer to it, so that they can adjust their braking and know exactly where to turn if they intend to leave the main road or see vehicles or pedestrians.