An interior rearview mirror system for a vehicle includes an interior rearview mirror assembly and an information display operable to display information for viewing by the driver of the vehicle through a transflective mirror reflector of a reflective element of the interior rearview mirror assembly. Information display intensity of the information display is adjustable responsive to determination of a light level at the interior rearview mirror assembly by at least one photosensor. The information display is operable to display video images captured by a rearward facing video camera of the vehicle and the information display displays video images captured by the rearward facing video camera during a reversing maneuver of the vehicle. During a reversing maneuver of the vehicle, a signal indicative of the vehicle transmission being in reverse is communicated via a network bus of the vehicle to a control of the interior rearview mirror assembly.