This is the 11512th most frequent Russian word.
дорожном
"Дорожном" means "road-related" or "travel-related" in English.
The word 'дорожном' is used as an adjective modifying 'покрытии', indicating 'related to roads'.
Я заметил выбоину на дорожном покрытии.
I noticed a pothole on the road surface.
Here, 'дорожном' describes 'знаке', meaning 'pertaining to roads', referring to a road sign.
На дорожном знаке указаны расстояния до ближайших городов.
The road sign indicates distances to the nearest cities.
In this context, 'дорожном' is used to describe 'инспекторе', meaning related to 'traffic or roads'.