When driving on rural roadways, be extra alert and watch for warning signs that communicate changes in road

When driving on rural roadways, be extra alert and watch for warning signs that communicate changes in road CONDITIONS or DIRECTION.

Explanation:

Even though there is less traffic in rural areas those roads remain as dangerous as crowded highways. There are some potential hazards in rural areas that you should be aware of: unmarked field and farm driveways and entrances, livestock crossing areas and farm vehicles, rough road CONDITION. Also, when you drive on countryside road with the similar landscape for a long period of time, be aware of a CONDITION known as “highway hypnosis" which can results in driving in a dulled, drowsy, trance-like state.

i have to go with a for this one

productive most commonly means: achieving or producing a significant amount or result.

explanation:

productive can also mean:

these depend on how the word productive is used. most likely productive will mean   achieving or producing a significant amount or result.