Municipal Device (Y-shaped figure)
The Y figure represents the Chicago River, north and south branches. In some uses of the figure, the word “Chicago” appears at the top of the circle, the words “I Will” appear above the Y, and the words “opportunity and a square deal” appear within the bottom of the circle.
As stated in the Municipal Code:
1-8-070 Municipal device-City vehicle identification.
The municipal device, for use by the varied unofficial interests of the city and its people, shall show a Y-shaped figure in a circle, colored and designed to suit individual tastes and needs. All automobiles and other vehicles which are owned by the city, except those used by the commissioner of police, and the detective bureau of the department of police, shall be distinctly marked as the property of the city by painting or placing thereon in a conspicuous place, in such a manner that the same cannot be removed, the municipal device, together with the words "City of Chicago," and the name of the department operating the said automobile or other vehicle. (Prior code 2-7)