(625 ILCS 5/1-135) (from Ch. 95 1/2, par. 1-135)

Sec. 1-135. Lane-control signal.

An official traffic control device consisting of an electrically controlled and illuminated signal of a square or rectangular design and employing distinctive colors or symbols used to control the direction of vehicular flow on the particular lane to which the indication applies.

(Source: P.A. 76-2122.)