Should CBD parking be buried?

The City of Melbourne's planning committee is set to consider a new policydesigned to improve the way private developments relate to the street. A lot of the ideas are good ones (there're 46 of them!) but it's very hard to impose "good design" by regulation, so it's unsurprising that some of the proposed initiatives are problematic.

Last week The Age highlighted a specific proposal to ban above-ground car parking – usually on the levels immediately above the ground floor – in new buildings (Highrise car parks to be banned in drive to improve city streetscapes):

Underground car parking would be the only type allowed in most city apartment and office developments, under new rules being considered by Melbourne City Council. And skyscrapers that cannot have underground parking because of soil conditions would instead have to ensure car spaces built on lower levels had high enough ceilings to later be converted into places for people to live.

The proposal only relates to developments in the extended CBD. Although it's complicated because the state government is the approval authority for larger developments in this area, it's worth asking if this is a good idea. Is it good policy?

As usual with the City of Melbourne, Councillors will decide without regard to what the implications might be for development within the City. In particular, they're given no analysis of the economics of how this change might impact development and hence potentially the supply of new housing and office space. Good design can potentially save money, but the case has to be made.

The rationale is improved appearance of the streetscape and greater passive surveillance of the street from windows on lower floors, but both of these putative benefits are exaggerated.

Given the right incentives, architects and regulators are quite capable of working together to design car park levels with visually interesting facades. It's not as if every apartment or office tower is automatically rendered beautiful by a uniform curtain of windows and/or balconies from top to bottom! In any event, the proposed policy envisages setting up design panels to improve the overall appearance of buildings, so it's odd that it abandons all hope in this particular application.

Passive surveillance is arguably the most over-worked concept in urbanism, routinely and reflexively wheeled out without much evidence to justify almost anything and everything (see Is "eyes on the street" straining it?). It's of limited benefit in cases like this where apartments and offices have double glazing to shut out street noise, aren't occupied for much of the day, and in many cases are visually separated from the street by awnings and/or trees.

What matters much more is activation at ground floor level; something this policy seeks to strengthen in other proposed provisions. The envisaged changes to parking would only apply in the extended CBD; a very small area where the sheer density of activity in any event means there are often people on the streets for most of the day.

Requiring new above-ground car parks in Southbank to have 3.5-metre-high ceilings so they can potentially be re-purposed as apartments might seem like a sensible idea at first glance because it seemingly enhances future flexibility; but it's more complex than that.

It will impose higher construction costs, but Council doesn't know how much. The future is extraordinarily hard to predict; it might be that in the long term the higher cost exceeds the benefit. Perhaps other uses will supplant apartments in this location in the future – potentially making the flexibility redundant – in the same way they've been preferred more recently over office uses.

Or perhaps the car parks will last as long as the life cycle of the building. After all, the City of Melbourne can hardly be described as taking concerted action to diminish car parking within the municipality.