49 CFR 3.1 - Description.
The official seal of the Department of Transportation is described as follows: A white abstract triskelion figure signifying motion appears within a circular blue field. The figure is symmetrical. The three branches of the figure curve outward in a counter-clockwise direction, each tapering almost to a point at the edge of the field. Surrounding the blue circle is a circular ring of letters. The upper half of the ring shows the words “Department of Transportation”. The lower half of the ring shows the words “United States of America”. The letters may be shown in either black or medium gray. The official seal of the Department is modified when embossed. It appears below in black and white.