Abstract: An adjustable glarefoil assembly is provided for mounting to a median barrier which divides opposing lanes of a highway and operates to reduce the glare of headlights from oncoming vehicles. The glarefoil assembly includes a plurality of glarefoil blades which are adjustably coupled for angular movement with respect to a base runner section in an appropriate light blocking orientation. The base runner section is rigidly mounted to the top of the median barrier at between three and five spaced points, thereby preserving some latitude for vibrational movement within the base runner section. The glarefoil blades are each adjustable about a vertical, longitudinal axis so as to optimally provide sight obstruction for a variety of different road curvatures, as well as maintaining the best possible angle to prevent wind build-up.