A request from Conway Mayor Tab Townsell has prompted the state Highway and Transportation Department is to study a third plan for a new Interstate 40 interchange. The department had presented two plans at a public hearing on November 13th. But Townsell said that he`s asked for a review of a third option to convert the Arkansas 25 interchange, on the north side of Conway, into a full interchange. The project would have both eastbound and westbound exit ramps, easing congestion around the U.S. 65 interchange. Townsell says a cost estimate isn`t available yet for the new option. Construction could begin as early as late next summer or early fall of next year. Conway has more than 45-thousand residents, according to U-S Census Bureau estimates. Its population grew by more than 50 percent between 1990 and 2000.