Green vs Black USBRS Signs
Black & White USBRS Sign: This black version of the M1-9 USBR sign is the one found in the 2009 edition of the MUTCD.
Green USBRS Sign: The green version was designed and endorsed by the National Committee on Uniform Traffic Control Devices to replace the older black version. In 2012, the FHWA gave interim approval for the optional use of the green M1-9 sign. The latest edition of the MUTCD has formally approved the use of the green M1-9 sign.
For more sign resources and examples, check out Promotion Resources.
Photo by Kansas Department of Transportation