This is the 7559th most frequent Russian word.
дорожное
"Дорожное" means "road-related" or "pertaining to roads."
In this sentence, "дорожное" is used as an adjective describing "движение" (traffic), meaning it pertains to the roads.
Дорожное движение сегодня очень интенсивное.
The road traffic is very heavy today.
Here, "дорожные" is an adjective modifying "знаки" (signs), indicating that the signs are related to road usage.
Установили новые дорожные знаки на всей улице.
New road signs were installed along the entire street.
In this usage, "дорожное" describes "состояние" (condition), referring to the state or conditions of the roads.