An interior rearview mirror assembly for a vehicle includes a mirror head having a reflective mirror element, and a mirror mount for attaching the interior rearview mirror assembly to an attachment element attached at an interior portion of the vehicle. When the mirror mount is attached to the attachment element, the reflective mirror element has a field of view rearward of the vehicle. The interior rearview mirror assembly includes a pivot joint enabling a driver of the vehicle to pivotally adjust the mirror head to set the rearward field of view of the reflective mirror element to the driver's desired setting with the interior rearview mirror assembly attached to the attachment element. The interior rearview mirror assembly includes circuitry, and the circuitry comprises at least one of (a) a transmitter for a toll booth transaction function and (b) a receiver for a toll booth transaction function.