[1] The M2 route replaces the motorway sections of what was known as Metroad 2 from 1993 to 2013, with the non-motorway sections replaced by the A2 route (made up of Windsor Road and Old Windsor Road).

The Lane Cove Tunnel was open to traffic in March 2007.

Prior to the opening of the Lane Cove Tunnel, the Metroad 2 followed Epping Road, between the Pacific Highway and Mowbray Road west.

These former stretches were parts of State Routes 28 and 30 until Metroad 2 replaced them in November 1993.

In 2013 with the introduction of alphanumeric route numbers in New South Wales, Metroad 2 was decommissioned, with the motorway sections replaced by route M2, and the non-motorway sections (Old Windsor Road and Windsor Road) receiving the A2 marker.