South Gippsland Freeway

The freeway originally began as an overflow from construction of the Mulgrave Freeway (now the Monash Freeway) in 1970, where the Mulgrave entered a sweeping turn south, crossed Eumemmerring Creek in Doveton and officially terminated at Princes Highway just outside Dandenong. This intersection was later replanned as a proper underpass and the freeway was unofficially extended under the Princes Highway to run a kilometre further south, along the eastern border of Melbourne's Holden factory at the time, to terminate at the original alignment of the South Gippsland Highway where it met Pound Road.

Some years later, due to the unforeseen success of this section of the freeway, it was redeveloped and "extended" another kilometre south towards Lyndhurst. The old alignment of the South Gippsland Highway was duplicated and upgraded into the new stretch of the freeway, and a new dual-carriageway alignment of the South Gippsland Highway was constructed approximately a kilometre to the freeway's west. Pound Road was extended a few hundred metres west across a new bridge over the freeway, and Dandenong-bound ramps were constructed. The interchange (Lyndhurst interchange) where the freeway and the old and new alignments of the South Gippsland Highway met Lyndhurst Road (renamed Hastings-Dandenong Road not long afterwards) was reconstructed to allow the freeway to flow further south using an overpass above the realigned South Gippsland Highway: those wanting to follow the highway to Cranbourne or beyond simply used the off-lanes.

The Doveton segment of freeway between Eumemmerring Creek and Princes Highway was originally named the Eumemmering Freeway.[3] By 1975 it had been renamed the South Gippsland Freeway.[4]

By 1988, the Mulgrave Freeway — rechristened as the South Eastern Arterial at this stage — had been over time extended and then linked to allow a freeway-style link from the city to Dandenong; this translated into a heavier use of the South Eastern Arterial and by extension the South Gippsland Highway. Not much was done to improve the freeway however, especially for the Doveton segment, which saw traffic volume leap as drivers used it to gain access to Princes Highway east beyond Dandenong and the suburbs beyond. As the entire South Eastern Arterial was designated a State Route 1 shield (later converted to M1), this section was also designated the same route: state route 65 was designated to the stretch south of the Princes Highway beyond to Hastings-Dandenong Road (now Dandenong-Hastings Road). The bridge over the Lyndhurst interchange was eventually duplicated with little fanfare in the early-1990s, leading to increased use of the road, mostly to semi-trailers and the amount of freight using the road to get to the docks in the Westernport district: Dandenong-Hastings Road was yet again renamed the Western Port Highway to reflect this and was eventually duplicated in stages.

The freeway had its metro shield abolished when Victoria switched to the alpha-numeric route system some years later, and was given the M420 designation for the southern segment of the freeway (which extended to the southern portion of the South Gippsland Highway beyond the Lyndhurst interchange, the Westernport Highway was given the A780 designation): the northern segment still retained the M1 designation until the Southern Eastern Arterial — renamed yet again to the current Monash Freeway — was extended further south-east from Doveton along the planned alignment (the "Hallam Bypass") to Berwick in 2003. The northern segment assumed the M420 designation afterwards.

In 2010, the Pound Road half diamond interchange is being substantially upgraded with a new four lane carriageway being constructed over the freeway, with the addition of traffic lights to the on-ramp intersection, and ramp metering signals. These works were completed late 2011.

In recent years, the M420 Fwy has become very busy, carrying high volumes of traffic off the South Gippsland Highway, Western Port Highway and the Pound Road and Princes Highway on-ramps. The freeway attracts all these vehicles, a large proportion of which are freight (hence two ramp metering sites inbound have a priority lane), due to the Monash Freeway which connects to it, being the major south-east freeway leading to Melbourne City. It is also the only freeway (or non-tollway, such as EastLink) to the City. It has led to slow or heavy traffic (inbound) during the morning peak and gets even more congested when the Monash Freeway is already heavy. Outbound is not so bad, although when very heavy traffic comes off the Monash Freeway (outbound), it can cause a bottleneck near and around the Princes Highway interchange, so a ramp signal site was installed to meter out traffic and reduce flow breakdown.

So, as part of the major 2007 M1 (Monash-CityLink-WestGate) Upgrade; which included widening to more lanes, updates to safety, electronic drive time signs and associated arterial road real-time information signs and a freeway management system with ramp metering (key component). The M420 Freeway was also upgraded to include a Freeway Management System, from its start at the South Gippsland Highway interchange to the Monash Freeway junction. It added Ramp Metering signals to the South Gippsland Freeway / Pound Road / Princes Hwy (inbound) on-ramps (the outbound on-ramp already had an existing metering site). With this, it also included electronic real-time information signs on the three inbound on-ramps, showing travel times and flow conditions downstream from that respective location to either destinations on the Monash Freeway and/or South Gippsland Freeway. Therefore, it also included installation of hundreds of new in-road sensors on the freeway with associated access point poles, data stations and CCTV cameras. It is completely integrated with the M1 Monash Freeway.

• 1972 - 5.6 km between the Princes Highway, Hallam to Stud Road, Dandenong North opened 21 November 1972, by His Excellency the Governor of Victoria. The section between the Princes Highway and the bend to the north-west was originally referred to as the Eumemmerring Freeway. From the bend to Stud Road was the initial section of the former Mulgrave Freeway (now the Monash Freeway).[3]
• 1976 - Dual carriageways completed between the Princes Hwy, Hallam and Pound Road, Hampton Park, as well as the south-bound carriageway to Dandenong-Hastings Road. Opened 6 December 1976 at a cost of $12m.[4]
• 1977/78 - North-bound carriageway from Pound Road to Dandenong-Hastings Road completed.[5]

The standard travel time on the South Gippsland Freeway, is 4 minutes (inbound) and 3 minutes (outbound). (Inbound: between the South Gippsland Highway and the Monash Freeway. Outbound: the same but back-to-front).

The usual peak period travel time, is between 6–8 minutes. However, in times of extreme congestion or roadworks, including being residual due to an incident, the travel time can well exceed 10 minutes.

• Freeways in Australia
• Freeways in Melbourne
• Road transport in Victoria