An exterior electrochromic reflective mirror element for a vehicular exterior rearview mirror assembly comprises an electrochromic cross-linked polymeric solid film disposed between a first substrate and a second substrate. The electrochromic cross-linked polymeric solid film contacts a transparent conductive layer of the first substrate and a conductive layer comprising a metallic reflective layer of the second substrate. A visual indicator display is disposed to the rear of said second substrate and is part of a blind spot detection and display system and is actuated to emit light responsive to a detection of another overtaking vehicle in a side lane. Light emitted by the visual indicator display passes through the second substrate, through the electrochromic cross-linked polymeric solid film and through the first substrate to be viewed by a driver of the vehicle equipped with the exterior electochromic reflective mirror element.