Сиднейдің батыс айналма жолы: A9 бағытының сипаттамасы

The A9 is a route designation of the outer western Sydney Bypass, connecting Windsor to Campbelltown via Penrith. This name covers a few consecutive roads and is widely known to most drivers, but the entire allocation is also known – and signposted – by the names of its constituent parts: Macquarie Street, George Street, The Northern Road, Richmond Road, Parker Street and Narellan Road.

The A9 commences at the intersection of Macquarie Street and Bridge Street in Windsor and heads in a southwesterly direction as Macquarie Street as a four lane, single carriageway road, narrowing to two lanes through South Windsor, and then intersects with and changes name to George Street shortly afterwards, eventually meeting Blacktown Road at a roundabout at Londonderry. It runs briefly southeast along Blacktown Road, before following The Northern Road at another roundabout, heading again in a southwesterly direction, before heading south at Llandilo. It changes name to Richmond Road and widens to a four lane, dual carriageway road at Cranebrook and continues south, changing name again to Parker Street in Penrith, before meeting Great Western Highway a short distance later and widening to a six lane, dual carriageway road. Parker Street continues south, changing name back to The Northern Road in South Penrith, crosses M4 Western Motorway, narrows back to a four lane, dual carriageway road, and continues in a southerly direction through Bringelly to eventually meet Camden Valley Way at Narellan. It changes name one final time to Narellan Road and heads southeast, before eventually terminating at the interchange with Hume Motorway on the northern fringes of Campbelltown. The A9 is also the major link between the International Regatta Centre at Cranebrook and M4 Western Motorway. It was upgraded just before the Sydney 2000 Olympics.

The passing of the Main Roads Act of 1924 through the Parliament of New South Wales provided for the declaration of Main Roads, roads partially funded by the State government through the Main Roads Board (later the Department of Main Roads, and eventually Transport for NSW). Main Road No. 154 was declared from the intersection with Hume Highway (today Camden Valley Way) in Narellan, via Bringelly and Luddenham to Llandilo (and continuing northwards to the intersection with Windsor Street in Richmond), to provide for additional declarations of State Highways and Trunk Roads, this was amended to Main Roads 154 and 178 and 184 on 8 April 1929. The northern end of Main Road 154 between Llandilo and Richmond was later re aligned to run from Llandilo to Windsor on 8 December 1937. Main Road 154, previously named Bringelly Road, was later renamed The Northern Road (between Blacktown Road in South Windsor and the intersection with Andrews and Richmond Roads in Penrith, and the intersection of Maxwell and Parker Streets in South Penrith to the intersection of Hume Highway – today Camden Valley Way – and Narellan Road in Narellan) on 14 January 1981. The passing of the Roads Act of 1993 updated road classifications and the way they could be declared within New South Wales. Under this act, the A9 retains its declaration as Main Roads 154 (as Macquarie and George Streets and The Northern Road) and 178 (as Narellan Road), and part of Main Road 184 (Macquarie Street through Windsor). The route was allocated part of State Route 69 in 1973, linking to via Sydney's western suburbs, along Putty Road, the current A9 route, and Appin Road. It was replaced by Metroad 9 between Windsor and Campbelltown in December 1998, with State Route 69 consequently split into two sections: a northern section along Putty Road connecting Windsor to Singleton, and a southern section along Appin Road connecting Campbelltown to Wollongong via Princes Motorway. With the conversion to the newer alphanumeric system in 2013, Metroad 9 was replaced by route A9, and the southern section of State Route 69 (Appin Road) was replaced by route B69; the northern section of State Route 69 (Putty Road) was left unallocated.

As part of the Western Sydney Infrastructure Plan, of The Northern Road will be upgraded to a minimum of four lanes between The Old Northern Road at Narellan and Jamison Road at South Penrith. The project is being delivered in six stages, with the first stage at Oran Park completed in April 2018. In April 2020, The Northern Road was also realigned between Mersey Road and Eaton Road at Luddenham, to facilitate the construction of Western Sydney Airport. On 16 July 2020, The Northern Road and Bringelly Road interchange opened including a realignment of The Northern Road. On 13 December 2020, The Northern Road was realigned between Elizabeth Drive and Eaton Road was opened to traffic, bypassing Luddenham. The rest of The Northern Road upgrade was completed through 2021, with the final upgrade opened to traffic in December 2021.

As part of economic development of western Sydney, including the construction of the Western Sydney Airport at , the road was proposed to be upgraded to a grade separated motorway. The proposal, known as the M9 Outer Western Sydney Orbital motorway, would link the M31 near Appin with the Central Coast via , and
As part of the State Budget 2014–15, the NSW Government announced a $5.5 billion road package for Western Sydney. It includes $4.6 million for planning the M9 Motorway. The preferred corridor for the motorway was expected to be announced later in 2014 before plans are made for reserving land. The corridor is now known as Outer Sydney Orbital with motorway codenames as either M9 or M10.