Question Unless otherwise posted, the speed limit on state highways is: Answers 55 mph. 65 mph. 75 mph. Explanation When driving on a state highway, the speed limit is 55 miles per hour. If a different speed limit is posted, follow the posted speed limit. Pass your DMV Written Test with flying colors Take me to the cheat sheet Kentucky This questions appears in the following tests: Kentucky Practice Test 21 Kentucky Practice Test 36