Arkansas is still at 55 mph for 2 lane roads, whether they have wide shoulders or not. Exceptions are "super 2" highways like AR 530 (and formerly 549 around the Bella Vista area) which have 65 mph limits. Their "5 lane freeways" are 60 mph in rural sections. A lot of 2 lane highways east and south of the hilly areas of the state (Ouachita and Ozark mountains) could use either 60 or 65 mph on 2 lane roads... and "5 lane freeways" could be increased to 65 or 70 mph, depending on sight lines, curves or lack of, and so on.