Question Unless otherwise posted, the maximum speed limit on a rural interstate is: Answers 70 mph. 55 mph. 40 mph. Explanation When driving on a rural interstate, the speed limit is 70 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 Mississippi This questions appears in the following tests: Mississippi Practice Test 12 Mississippi Practice Test 2