U.S. Department of Transportation
Federal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC 20590
Image contains two diagrams illustrating options for making vehicles go around the center island to make a left turn. Diagram 'a' illustrates that by moving the entrance line forward beyond the outer edge of the circle's diameter, vehicles will be encouraged to go around the center island to make a left turn. Diagram 'b' illustrates that enlarging the central island is another way to direct vehicles to go around the island to make a left turn rather than turning before the center island.