Gawler Bypass is a major north–south route in the outer northern suburbs of the city of Adelaide, South Australia. It had the nationaldesignation of National Highway A20 north of the Northern Expressway, while south of this intersection it had the state designation of A52. From late 2016, the entire length was designated A20, corresponding to the Northern Expressway being designated M2. It is a freeway standard route connecting Main North Road to the Sturt Highway, bypassing Gawler. Major exits include Angle Vale Road, Two Wells Road, Northern Expressway, Mallala Road and Horrocks Highway. Each of these exits also have minor roads leading into Gawler. The route was built in 1963 in an attempt to redirect traffic on the national highway out of Gawler town centre and has been upgraded and realigned several times since then.
History
The first Gawler bypass was planned in the 1950s and built as a single two-lane carriageway around the town in 1963 with at-grade intersections and carried 3,000 vehicles per day. It ended at a tee-junction at the southern end, and followed an alignment that included what is now the southbound on-ramp and Brereton Road, Jack Cooper Drive over the Winckel Bridge, and Paternoster Drive to the railway bridge. The next advance developed the road to dual carriageway with grade-separated intersections at the southern end in the 1980s and new bridges over the Gawler River. When it was approved, the 1963 bypass was carrying 7000 vehicles per day, and 300 collisions had been recorded between 1977 and 1982. Improvements to the Sturt Highway have included upgrades to the northern end of the Gawler Bypass to facilitate smooth flow between them, completed in 2010. The construction of the Northern Expressway in 2010 resulted in realignment of the northbound carriageway as part of creating a grade-separated intersection with smooth flow between the northern section of the Gawler bypass and both the Northern Expressway and the southern part of the Gawler bypass. As both roads lead broadly south, there is no provision to turn directly from one to the other.
