"This sign is used to display the limit established by law, ordinance, regulation, or as adopted by the authorized agency. The speed limits shown shall be in multiples of 10 km/h or 5 mph." -Federal Highway Administration, 2007
Federal Highway Administration Manual on Uniform Traffic Control Devices for Streets and Highways, 2003 Edition (including 2004 and 2007 revisions) (Washington, DC: United States Department of Transportation, 2007)
