Urban renewal options in and around Melbourne's CBD (Source: DPCD)

Victoria’s Planning Minister (for the moment, anyway), Matthew Guy, is in the sights of both The Age and Melbourne City Councillor, Stephen Mayne, over approval processes for city centre buildings and his relationships with developers.

While there’s no evidence of improper behaviour, it’s a headache any Minister would prefer went away.

That might explain Mr Guy’s rush last week to announce a new organisation to manage strategic planning implementation in Melbourne.

This new initiative comes even though the public comments on the discussion paper for the Melbourne metropolitan strategy, which has a section on governance options, don’t close until the end of the month.

Pre-empting important policy choices isn’t unprecedented on Mr Guy’s watch.

The discussion paper itself makes two significant policy commitments, notwithstanding that it’s theoretically supposed to support and enable the public consultation process for the strategy.

One commitment is to a “20 minute city”, which I’ve discussed before (here and here). The other commitment – which I want to discuss this time – is to “a polycentric city”.

The idea is to encourage a metropolitan structure where the dense CBD and inner city are complemented by a handful of major suburban clusters of jobs and services.

I’ve argued for years that the merits of the polycentric urban structure need to be brought into the policy frame and given serious consideration.

But I don’t think its virtues are so obvious that it should be treated as ‘a given’ and exempted from public consultation!

Significant policies should be regarded as contestable at the start of a process as far-reaching as the development of a metropolitan strategy (the last one, Melbourne 2030, was finalised in 2002).

The discussion paper insists that “initial urban form modelling” suggests a polycentric metropolitan structure performs best “in terms of increased public transport use and reduced traffic congestion.” Yet remarkably, it provides no evidence to support this assertion – where is this “urban form modelling”?

There are a number of issues around the polycentric city idea that really ought to be on the table.

First, suburban firms in Melbourne have a distinct preference for low density dispersal. Only around 20% of suburban jobs could be considered to be in clusters or centres even assuming a very low density threshold (see here, here, here , here and here).

That seems to be primarily because most suburban firms in Melbourne gain little benefit from even quite modest densities. Planning restrictions that make some centres too expensive also have a role, but they doesn’t appear to be the key reason.

Second, Melbourne’s seemingly inexhaustible ability to expand the size of its CBD has a large impact on whether or not the sorts of firms that value density need to seek out dense suburban locations.

The CBD has already expanded into Docklands and Southbank. Moreover, the Government has signalled its enthusiasm for redevelopment of other former industrial near-CBD areas, including Fishermans Bend, North Melbourne and E-gate.

Melbourne’s CBD is so ‘elastic’ that firms like NAB can afford to locate even their extensive backoffice functions downtown in large floorplate low-rise complexes. Elsewhere, these sorts of ‘routine’ functions are usually located in low-cost places like the suburbs or regions.

There’s a clear relationship between what happens in the centre and the prospects for dense employment concentrations in the suburbs.

Third, there’s research that suggests if firms locate in large suburban concentrations rather than the city centre, commutes may on average be longer.

That’s because suburban centres don’t operate as idealised villages drawing workers solely from their immediate catchment.

Rather, they attract workers from across the metropolitan area, leading to longer average trip distances compared to trips to the (almost geometric) centre.

This is modified but isn’t prevented by traffic congestion. It happens even after sufficient time elapses to enable some workers to “sort” into residential locations near their work.

Finally, the share of journeys made by public transport to suburban centres may also be lower if those firms would otherwise have located in the city centre.

The level of congestion is lower in smaller centres and so it’s less effective in discouraging car use than it is in the city centre. In addition, transit’s geographical reach from most suburban centres is a far cry from that offered by the centre of the city.

Irrespective of the merits of the argument for a polycentric urban form, the sorts of issues I’ve nominated above indicate it’s not received wisdom. It’s just another policy prescription that should be subject to examination, not assumed to be beyond debate.

An effective consultation process would go further and provide information and data around the various urban form options to help operationalise debate.

There’s a long history of ‘Claytons’ public consultation in strategic planning. It’s invariably treated as a compliance exercise, not a positive way of improving the outcome.

Mr Guy has taken a “hands-off” approach to the metropolitan strategy, effectively sub-contracting the process to a Committee of experts he appointed (the Ministerial Advisory Committee).

It may be time that he, or his replacement if the new Premier opts to calm the waters by appointing a new face to the planning portfolio, took a stronger interest in the preparation of the strategy.