Construction of the M4 was initiated in response to the need to provide an efficient link through Sydney's western suburbs and between western Sydney and the inner-west. The motorway was designed to provide a direct link between key regions in western Sydney, reduce travel times between these regions, and provide a gateway to western Sydney.
On 16 February 2010, operation of the M4 Motorway was handed back to the NSW Government and the toll was removed.
- Quicker journey times. The M4 provides a faster trip than alternative routes over its entire length, including travel during peak traffic periods.
- Improved traffic flow. The M4 bypasses 40 kilometres of intersections and 60 sets of traffic lights.
- Improved commute times for residents working in the inner-west and Central Sydney areas.
- Access for cyclists along the shoulder of the M4, except on the section between Silverwater Road, Auburn and Church Street, Parramatta.
- Most of the M4 has three lanes in each direction.
- Sixteen major interchanges, including a connection to the M7.
- Posted travel speeds range from 90km/h to 110km/h.