Abstract: The present disclosure is directed to an adjustable mud flap assembly and associated mud flap material. The adjustable mud flap assembly includes a motor, a motor housing, a mud flap extension bar connected to the motor housing, a sheet of mud flap material wrapped around a drive bar which is housed within a mud flap extension bar and a motor drive shaft which rotates or drives operation of the drive bar and the extension or retraction of the mud flap material from an opening at the bottom side of the mud flap extension bar.