A side mirror assembly (1; 101) for a ground vehicle (3; 103), the side mirror assembly (1; 101) comprising two mirrors (5, 6; 105, 106) distributed parallel to a main axis (Z12; Z112) of the side mirror assembly (1; 101), and both configured to be secured to the ground vehicle (3; 103), the main axis (Z12; Z112) is parallel or slightly inclined relative to a height direction, vertical in normal situation of usage of the vehicle; wherein the side mirror assembly (1; 101) comprises a spacer actuator (20; 120) for moving the two mirrors (5, 6; 105, 106) relative to each other, between: - a primary position, wherein the mirrors (5, 6; 105, 106) are at a first distance (Zd1; Zd101) from each other along the main axis (Z12; Z112); and - a secondary position, wherein the mirrors (5, 6; 105, 106) are at a second distance (Zd2; Zd102) from each other along the main axis (Z12; Z112), the second distance (Zd2; Zd102) being greater than the first distance (Zd1; Zd101); and wherein, - at least when the mirrors (5, 6; 105, 106) are in the secondary position, at least one empty see-through opening (22, 24; 122) is provided along the main axis (Z12; Z112), between the mirrors (5, 6; 105, 106), so that a user may see beyond the side mirror assembly (1; 101) through said at least one see-through opening (22, 24; 122); - the side mirror assembly (1; 101) comprises a main control unit configured for automatically selectively setting the mirrors (5, 6; 105, 106) to the primary position and to the secondary position by controlling the spacer actuator (20; 120); - the main control unit is configured for automatically setting the mirrors (5, 6; 105, 106) to the primary position and to the secondary position depending on operating data of the ground vehicle (3; 103), the operating data preferably including at least one of the following: ground vehicle speed, ground vehicle steering, and vehicle travel direction. - a primary position, wherein the mirrors (5, 6; 105, 106) are at a first distance (Zd1; Zd101) from each other along the main axis (Z12; Z112); and - a secondary position, wherein the mirrors (5, 6; 105, 106) are at a second distance (Zd2; Zd102) from each other along the main axis (Z12; Z112), the second distance (Zd2; Zd102) being greater than the first distance (Zd1; Zd101); - at least when the mirrors (5, 6; 105, 106) are in the secondary position, at least one empty see-through opening (22, 24; 122) is provided along the main axis (Z12; Z112), between the mirrors (5, 6; 105, 106), so that a user may see beyond the side mirror assembly (1; 101) through said at least one see-through opening (22, 24; 122); - the side mirror assembly (1; 101) comprises a main control unit configured for automatically selectively setting the mirrors (5, 6; 105, 106) to the primary position and to the secondary position by controlling the spacer actuator (20; 120); - the main control unit is configured for automatically setting the mirrors (5, 6; 105, 106) to the primary position and to the secondary position depending on operating data of the ground vehicle (3; 103), the operating data preferably including at least one of the following: ground vehicle speed, ground vehicle steering, and vehicle travel direction.