600 mm by 600 mm (24 in by 24 in) Interstate shield, made to the specifications of the 2004 edition of Standard Highway Signs (sign M1-1) and modified to fit the Oklahoma standards. Uses the Roadgeek 2005 fonts. (United States law does not permit the copyrighting of typeface designs, and the fonts are meant to be copies of a U.S. Government-produced work anyway.) Colors are from [1] (Pantone Red 187 and Blue 294), converted to RGB by [2]. The outside border has a width of 1 (1 mm) and a color of black so it shows up; in reality, signs have no outside border.
Based on Image:I-235.svg
Scott Nazelrod, SPUI