Adjunct Professor Evan JonesBrookfield Multiplex

In collaboration with Chip Kaufman, Ecologically Sustainable Design, Melbourne

Optimizing Urban Structure: Towards an Integrated New Urbanist Model

CNU 17 June 2009

Today’s discussion

There is an important debate underway amongst New Urbanists about the structuring of neighbourhoods with their movement networks and how their forming of larger corridors, towns and cities can optimize prosperity, public transport and urban sustainability.

This paper reviews traditional Australian structuring and its influence on the development of Australian New Urbanism. This content may reveal opportunities for improvement in the structuring of New Urbanism beyond Australia.

Part 1

Australian Urban Models:

Perth, Melbourne, Brisbane

Hillarys – Land use mapSingle ResM.D. ResH.B.B.RetailCommercialBulky GoodsLight Ind.CommunityParks

Subiaco – Land use mapSingle ResM.D. ResH.B.B.RetailCommercialBulky GoodsLight Ind.CommunityParks

Australian Urban Models: Case Study # 1. Perth How Suburbs Work - Diversity

• Diversity of Land Use

• Connectivity• Permeability• Accessibility• Land Use• Diversity• Residential

Densities• Worker

Densities• Diversity of Lot

Sizes• Energy Use

Not only is the notional catchment for Hillarys much larger, there is also a greater proportion of the area (shaded red) with no proximity to any centre at all. This area is highly car dependant on the Hillarys regional centre.

Sprawl Suburb: Hillarys

Traditional Suburb: Subiaco

District

Centre

Town

Centre

The traditional Subiaco centre is smaller and supported by a cluster of neighbourhoods via direct transit connections. Subiaco as a result achieves much greater residential densities and employment self-sufficiency.

Australian Urban Models: Case Study # 1. Perth How Suburbs Work - Self-Sufficiency

1 Mile

Town and Neighbourhood

Structure

Australian Urban Models: Case Study # 2. Melbourne Town and Neighbourhood Structure

Mile grid with half-mile arterials and a smaller permeable street network, to minimise need for arterial and retail gigantism

1 Mile

1 Mile

Australian Urban Models: Case Study # 2. Melbourne Town and Neighbourhood Structure

Australian Urban Models: Case Study # 2. Melbourne

Town and Neighbourhood Structure

Australian Urban Models: Case Study # 3. Brisbane Town and Neighbourhood Structure

Brisbane Inner West

Town Structure

Neighbourhood Structure

Streets, Centres, Open Spaces

Hilly terrain inspires ridge roads and deforms the grid

Part 2

Integrated Urban Structuring in Australia

1. Walkable Neighbourhoods cluster together to form mixed use Towns

Typically in the Australian Liveable Neighbourhoods structure, the mixed use town centre serves around 15,000 to 30,000 people, and is supported by six to nine neighbourhoods.

It contains a main-street based convenience retail node ideally with two supermarkets, together with service businesses, substantial commercial uses, civic and recreational facilities.

Typically one in ten towns within a metropolis enlarge to become a regional centre, and contain major hospital, civic, educational and office uses. It serves around 100,000+ people.

Walkable Catchments and Bus RoutesEcologically Sustainable Design

• Relatively full range of uses compatibly mixed in close proximity

• Integrator arterial Road Network - no dividers

• Neighbourhood Connectors• Street Network &

Ped-sheds• Locating key land uses• Protecting heritage &

environmental assets• Providing for parklands,

schools and SUDS• Defining bus/fixed transit routes• Capitalizing on the movement

economy• Locating and sizing centres

2. Detailing a Town and Neighbourhood Cluster

3. Various ways for Walkable Neighbourhoods to cluster together to form Towns

Near a freeway exit

Along a major arterial Perpendicular to a main arterial

At a waterfront

4. The Relationships between Town Centres and big Arterials

A. Main Street at right angles to big arterial, often with rail station

Jindalee TC Mungarie Park TC Point Cook TC

B. Main Street parallel to big arterial - needs good local street links to core customers

C. Main Street across corner of two big arterials

5. Regional Structuring Examples: Jindalee, North-West Corridor, Perth, WA 1996

Perth - Population: 1.4 million

Highly-planned ‘sprawl’ in ever-extending corridors - an urgent need to change as transport networks are now predicted to fail

Typical subdivision plans

1995 North-west Corridor Structure Plan

Scenario A Rail along Freeway, on edge of urban corridor. National Park to east

Scenario BRail part way into urban corridor, along Connelly Drive

Scenario C preferred Rail in the centre of the urban corridor

5. Regional Structuring Examples:Jindalee Regional Structure Scenarios

Testing by design at the more detailed scale, then re-adjusting the regional structure as necessary

5. Regional Structuring Examples: Jindalee Town and Neighbourhood Structure

Comparing Employment

Conventional DesignPopulation 29,259Dwellings 9,753Jobs Needed 14,629Proposed Jobs 2,612Containment Factor 18%

Liveable Neighbourhoods Design Population 30,234Dwellings 11,768Jobs Needed 17,652Proposed Jobs 11,306Containment Factor 64%

5. Regional Structuring Examples Jindalee - Measuring Outcomes

Two main remaining large growth areas totaling 26,000ha in the Sydney Basin, population 380,000

Joint public/private $7.8 billion infrastructure funding

Regional structure now set, detailed design to be administered by new Growth Centres Commission and local Councils

www.metrostrategy.nsw.gov.au

5. Regional Structuring Examples: Western Sydney Urban Land Release 2003-05

Consolidate and enhance key viable habitat fragments, remove others. Investigate spacing and linking of Town Catchments. Green network generally located between towns, not between neighbourhoods

Preliminary urban/green Preliminary town locations

5. Regional Structuring Examples: South West Sydney – urban structuring

Scenarios for Testing

South West SydneyFinal Adopted Plan

Rail to Leppington - a new Regional Centre

Bus transit boulevards to five town centres. Possible conversion of key route to LRT in future

Walkable neighbourhoods with local centres and bus routes on local arterialsGreen network and heritage farms between towns

Retail complementary instead of predatory

Molonglo Valley, Canberra

To ensure that places will work well, we need to design them out as pieces of cities and towns.

The structuring approach is based on good examples of traditional cities, together with responses to current parameters.

The town-scaled circle templates are a representation of what will work when adjusted to the site.

Constraints must be interrogated to ensure urbanism is not fractured by green.

5. Regional Structuring Examples: Conclusion

Part 3

International Practice

“It is no coincidence that Clarence Perry retreated to the centre, in a relatively isolationist, exclusive and defensive fashion, separating social institutions from the life of commerce which he kept on the edge. Oh, and by the way, he blew away Main Street in one fell swoop.” …Paul Murrain

Perry identified a walkable neighbourhood based on a five minute walk from community facilities within the centre of a residential ‘cell’. The commercial elements were located at the junction of the arterial routes. This diagram separates Community within a ‘neighborhood center’ from Commerce along arterials outside the neighborhoods.

The Perry Diagram

Clarence Perry (1920’s)

Traditional Neighbourhood Structure

Perry interpreted through Traditional Neighbourhood Structure, with a cluster of four Perry Neighbourhood Units - now with local retail internalized away from the movement economy and town centres artificially externalized

Key problems:

1. Neighbourhood Centres are only a quarter mile from the Town Centre - too close to complement each other with neighbourhood centres usually failing

2. This diagram limits a Town Centre’s own walkable catchment

Perry Transposed

By transposing the Perry circles onto the movement economy and commerce, the Liveable Neighbourhoods structure becomes apparent, whereby a cluster of neighbourhoods supports a town centre. Only land expansive community uses such as large-format schools are located in the interstices between neighbourhoods.

Routing Problem: with this diagram, Public Transport must either serve the town center along the main boulevard/s, or else also loop inefficiently through all four NCs, or both, all of which options will compromise transit times and services.

Relative performance: Public Transport

A Prototype for Heavy Rail with Feeder Buses: Bus routes feed each Neighbourhood Centre, en route through Town Centre, either running both north-south and east-west in an expansive region, or as localized ‘spider’ feeder route, supplementing heavy rail service

4 neighborhoods 8-9 neighborhoods (inc TC)

Retail Performance: Twice the capacity to generate sufficient population to enable a relatively self-sufficient mixed-use town center, which can improve on the role of large conventional stand-alone centers

Relative Performance: Centres

North Harlow a UK examples of public transport feeding neighbourhood and town centers directly

Plan courtesy of Paul Murrain

Relative Performance: Centres

Yard Houses

Mueller Plan, Austin, Texas Courtesy of Roma Design

Half-mile

NC’s seem to be only parks in this plan, whose Movement Economy (main traffic flows) supports neither the NCs nor the Town Centre

Neighbourhood Centres

1. Part of a larger supportive urban structure with an effective ‘pedshed’ to the centre

2. A corner store as the minimum facility for a neighbourhood centre.

3. Through streets with at least 5000-6000 total daily trips on them, serving around 1000 dwellings (ie. 17-20 dw/ha over 50-65 ha)

4. Corner stores typically small (150 -250sqm), and preferably combined with a multi-generational dwelling, and co-locating with childcare and home-offices and bus stop

Strand Neighborhood Center, Melbourne, now operating

Neighbourhood CentresKey Success Factors

Transit Corridor from Sustainable Urbanism, by Doug Farr

Attempts to illustrate transit for all modes - transit corridor bypasses neighborhood centers (only appropriate for heavy rail)39 neighborhoods but only one city/town center, and difficult, with paired neighborhoods, for others to mature into a larger center/s, supported by smaller ones clustering to it.

Regional Structuring Proposals

The Urban Network/Regional Transportation Structure - Calthorpe

This network isolates neighbourhood centres from the Movement Economy and locates town centres without catchments:

• The mile spacing induces bigger arterials and retail giganticism –Disconnecting neighbourhood centres a quarter-mile from the main movement economy kills off their retail viability – especially when traffic is kept

• secondary arterial network needs to function to reduce arterial road size

Regional Structuring Proposals

Are Australia and the US different - the diagram shows how structured urbanism fits within the Jeffersonian mile grid.

1 m

ileDiagram courtesy of Peter Richards

peter@drarchitects.com.au

Regional Structuring Proposals – A Liveable Neighbourhoods alternative

1 m

ile

NEW URBANISM(Project level)

SUSTAINABLE GROWTH MANAGEMENT

Urban, Transport and Natural Resource Context

Proj

ects

Sustainable Growth Management Model

Right Model + Planning Governance,

Infrastructure &Finance Mechanisms

Green and grey initiatives: water, energy, natural resources, materials, waste

New Urban and Transport Coding

available

Still in many Local Government codes

CONVENTIONAL(Sprawl)

Conclusions

Walkable Neighborhood Centers are a fundamental and necessary component of sustainable urbanism, but how we structure them together will ultimately determine the effectiveness of The New Urbanism

Neighbourhoods should be clustered to form cities and towns based on transit to deliver on the promise of sustainable development

Don’t segregate community from commerce, as Perry seemed originally to advocate.