§Speed Limit Sign (R2-1):
Not only is the shape, size, color, placement, hardware,
reflective backing quality and the breakaway post design
set by federal regulations, the practices and procedures to determine the safety value of the number on the sign and the exercise of police powers thereof SHALL also be fact based and uniformly applied regardless of state lines, entity type or classification on
any public or private roadway, pedestrian
facility or bikeway open to the public
within the U.S. and its territories.