Urban Form - OISDoisd.brookes.ac.uk/conferences/changetosurvive/resources/mikejenks... · Urban...

Urban Form: How sustainable can it be?

Urban Form:How sustainable can it be?

OISD Conference15 January 2008

Prof. Mike JenksDr. Nicola Dempsey

EPSRC GRANT No:GR/S20529/01OISD Oxford Brookes University, Heriot Watt University, IESD De Montfort University,

Sheffield University, Strathclyde University, Politecnico di Milano


Background


Unsustainable cities

• Problems recognised– Loss of agricultural land– Urban sprawl– Long journeys to work– Congestion and carbon

emissions– Environmental

degradation– Health concerns– Social exclusion, etc.


Sustainable urban form?

• Search for solutions to unsustainable cities• One ‘solution’ might be the compact city…

– … it appears to many to be a ‘ready-made solution’, and one for which a lot is claimed

• These are well known (but untested) urban forms– High density built form– Mixture of uses– The city is ‘contained’– Diverse, in terms of social and economic

activities


Aims & Scope


Urban form and sustainability

• To what extent and in what ways does urban form contribute to sustainability?– spatial sustainability– environmental sustainability– transport efficiency– social benefits– economic viability


City Form - Scope

Valuing Open Space

Urbanising Suburbia

CoreSustainable Urban Form

Urban Form

TransportEnvironmental

EconomicSocial

Sustainable Urban

Behaviour & Lifestyles


CityForm core case studies

• 5 cities– Edinburgh– Glasgow– Leicester– Oxford– Sheffield

• 15 case studies – 3 in each city

• Centre• In between• Suburb

– Approx 2,000 households or 20ha

• 97 sub-areas

Edinburgh

Sheffield

Glasgow

Leicester

Oxford


Core Research


Core – Urban Form

How is it measured?


Elements of Urban Form

TransportInfra-

structure

TransportInfra-

structure

Land UseLand Use LayoutLayout

Housing/Building

Type

Housing/Building

Type

DensityDensity

Urban Form

Urban Form


Edinburgh: integration (betweeness)


Edinburgh: urban form (400m res)


Edinburgh case study areas (vehicular)

Centre

Edge

In between


Urban form of the 97 sub-areas

City Form Sub areas (ped)

0. 0

0. 1

0. 2

0. 3

0. 4

0. 5

0. 6

0. 7

0. 8

0. 9

1. 0

G L_E_P_SA7 G L_E_P_SA6 G L_E_P_SA2 G L_E_P_SA8 O X_E_P_SA6 O X_E_P_SA4 O X_E_P_SA5 SH_E_P_SA5 ED_M _P_SA4 LS_E_P_SA2 SH_M _P_SA5 SH_M _P_SA7 O X_E_P_SA3 LS_E_P_SA3 O X_C_P_SA4 ED_M _P_SA2 LS_M _P_SA3 O X_M _P_SA4 LS_E_P_SA4 O X_E_P_SA1 SH_C_P_SA4 O X_M _P_SA1 O X_E_P_SA2 LS_E_P_SA6 O X_M _P_SA2 ED_E_P_SA3 SH_E_P_SA4 LS_C_P_SA7 ED_C_P_SA5 SH_E_P_SA2 LS_C_P_SA6 LS_C_P_SA5 SH_E_P_SA3 SH_M _P_SA2 SH_M _P_SA3 LS_C_P_SA4 ED_M _P_SA6 ED_C_P_SA4 O X_C_P_SA3 O X_M _P_SA5 G L_E_P_SA3 SH_E_P_SA1 ED_C_P_SA2 SH_E_P_SA7 SH_M _P_SA6 G L_E_P_SA1 G L_C_P_SA2 ED_M _P_SA1 G L_M _P_SA2 LS_C_P_SA3 O X_M _P_SA3 G L_M _P_SA1 O X_M _P_SA6 LS_E_P_SA7 O X_C_P_SA7 G L_M _P_SA3 O X_C_P_SA2 ED_M _P_SA5 G L_C_P_SA1 LS_E_P_SA5 O X_C_P_SA5 ED_M _P_SA3 ED_E_P_SA5 ED_E_P_SA2 ED_C_P_SA6 SH_C_P_SA3 LS_C_P_SA2 SH_M _P_SA1 ED_E_P_SA4 G L_M _P_SA4 LS_M _P_SA7 SH_C_P_SA5 O X_C_P_SA6 ED_E_P_SA6 G L_C_P_SA6 G L_C_P_SA5 G L_C_P_SA3 LS_M _P_SA6 LS_M _P_SA4 LS_E_P_SA1 G L_E_P_SA5 SH_M _P_SA4 SH_E_P_SA6 LS_M _P_SA2 O X_C_P_SA1 SH_C_P_SA6 G L_C_P_SA4 SH_C_P_SA1 SH_C_P_SA2 SH_C_P_SA7 G L_E_P_SA4 LS_C_P_SA1 LS_M _P_SA1 ED_E_P_SA1 LS_M _P_SA5 ED_C_P_SA3 ED_C_P_SA1

Emst

/Ene

t

(Source: Sergio Porta and Emanuele Strano, Politecnico di Milano)


Urban form


Core – Social sustainability


Elements of the social core project

• Conceptual exploration of social sustainability

• Household survey • Site observation surveys• Linkage to urban form measures,

neighbourhood socio-demographic data

• Focus groups • Study of perceptions of

neighbourhood


Social sustainability and density

Neighbourhood Pride & Attachment by Net Density - overall and urban form relationship

80.0

105.0

130.0

155.0

0.0 50.0 100.0 150.0 200.0 250.0 300.0 350.0 400.0

Net Dwellings /Hectare

Nei

ghbo

urho

od P

ride

Sco

re Pride

UF effect

Neighbourhood Interaction by Net Density - overall and urban form effect

90.0

100.0

110.0

120.0

130.0

140.0

150.0

0.0 50.0 100.0 150.0 200.0 250.0 300.0 350.0 400.0

Net Dwellings /hectare

Inte

ract

ion

Sco

re

Interaction

UF effect

Satisfaction with Home and Net Density - overall and urban form effect

100.0

120.0

140.0

160.0

0.0 100.0 200.0 300.0 400.0


Hom

e S

atis

fact

ion

Sco

re HomeSat

UF effect

Use Neighbourhood Facilities by Net Density - overall and urban form effect

80.0

90.0

100.0

110.0

120.0

0.0 100.0 200.0 300.0 400.0


Use

Fac

ilitie

s S

core

Use NHFac

UF effect


Core – Economic Sustainability


Residential viability

Edinburgh Glasgow

SheffieldLeicester

Oxford


Viability & urban form

• Offices– Viability dependent on agglomeration

economies traditionally focused on CBD– Rateable values show variations of viability

outside CBD – e.g. Oxford & Sheffield• Retail

– Density impact on trip flows - 10% increase in population = 11.6% increase in trip flows

• Infrastructure– Physical infrastructure costs increase by a

higher than proportional rate with falling density


Core – Environmental SustainabilityBiodiversity


Environmental – open space

-200 0 200 400 600 800 1000 1200

Total housing density

-10000

0

10000

20000

30000

40000

50000

60000

70000

Tota

l gre

en s

pace

(m2 )

-0.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5

Log (detached density)

-10000

0

10000

20000

30000

40000

50000

60000

70000

-0.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5

Log (semi density)

-10000

0

10000

20000

30000

40000

50000

60000

70000

-0.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5

Log (terraced density)

-10000

0

10000

20000

30000

40000

50000

60000

70000



Green space extent

Tree-cover Productivity

High

Low



0

200

400

600

800

1000

1200

1400

0 -

1.5

1.6

- 5.

3

5.4

- 14

.8

14.9

- 3

8.6

38.7

- 9

8.5

98.6

- 2

46

247

- 61

9

620

- 15

55

1556

- 3

021

3022

- 9

799

Housing density

Num

ber

of in

divi

dual

s

0

5

10

15

20

25

0 -

1.5

1.6

- 5.

3

5.4

- 14

.8

14.9

- 3

8.6

38.7

- 9

8.5

98.6

- 2

46

247

- 61

9

620

- 15

55

1556

- 3

021

3022

- 9

799

Housing densityN

umbe

r of

spe

cies

House sparrow

0

50

100

150

200

250

300

350

0 -

1.5

1.6

- 5.

3

5.4

- 14

.8

14.9

- 3

8.6

38.7

- 9

8.5

98.6

- 2

46

247

- 61

9

620

- 15

55

1556

- 3

021

3022

- 9

799

Robin

0

10

20

30

40

50

60

0 -

1.5

1.6

- 5.

3

5.4

- 14

.8

14.9

- 3

8.6

38.7

- 9

8.5

98.6

- 2

46

247

- 61

9

620

- 15

55

1556

- 3

021

3022

- 9

799

Magpie

0

5

10

15

20

25

30

35

0 -

1.5

1.6

- 5.

3

5.4

- 14

.8

14.9

- 3

8.6

38.7

- 9

8.5

98.6

- 2

46

247

- 61

9

620

- 15

55

1556

- 3

021

3022

- 9

799

Chaffinch

0

10

20

30

40

50

60

70

80

0 -

1.5

1.6

- 5.

3

5.4

- 14

.8

14.9

- 3

8.6

38.7

- 9

8.5

98.6

- 2

46

247

- 61

9

620

- 15

55

1556

- 3

021

3022

- 9

799


Core – Environmental SustainabilityEnergy


Results

• Simple linear regression: relationships– Significant - total floor area (TFA) and gas consumption – Strong - gas consumption for groups with some fabric types

(cavity filled walls)– Strong - gas consumption against TFA for households with the

highest level of heating system control– Strong - group reporting home-working

• Cluster analysis– No clusters associated with built form types– Two distinct groups of energy consumers strongly associated

with number of bedrooms • Multiple regression: best models

– Electricity - explained nearly 40% of consumption (TFA, occupancy, home-working, building age, no. of portable heaters, no. of TVs in use, washing machine use)

– Gas - explained nearly 47% of consumption (TFA, occupancy, no. of rooms, no. of bedrooms, home-working, thermostats and heating system controls, wall insulation, boiler type)


Simple regression: complete dataset and three subset data groups

Gas vs TFA, Combined datasety = 118.26x + 9853.6

R2 = 0.2857

0

10000

20000

30000

40000

50000

60000

70000

80000

0 50 100 150 200 250 300 350 400 450

m2

kWh

Gas vs TFA, Combined dataset, Cavity wallsy = 140.45x + 7800.7

R2 = 0.4617

0

10000

20000

30000

40000

50000

60000

70000

80000

0 50 100 150 200 250 300 350 400 450

m2

kWh

Gas vs TFA, Combined dataset, Homeworkersy = 145.77x + 8679.8

R2 = 0.4781

0

10000

20000

30000

40000

50000

60000

70000

80000

0 100 200 300 400 500

m2

kWh

Gas vs TFA, Combined dataset, TRVs, Digital controls and Thermostats

y = 174.22x + 3029.6R2 = 0.5782

0

10000

20000

30000

40000

50000

60000

70000

0 50 100 150 200 250 300

m2

kWh


Cluster analysis - spatial correspondence

“High” consumers

“Low” consumers

© Crown Copyright. Ordnance Survey. All rights reserved


Core - Transport


Access to services and urban form

• Accessibility profiles for key local services produced at individual address level and output area level

• Relationship between distance to urban centre, density & accessibility investigated


Walking time to access public transport for travel to work

Effect of walk time on mode choice

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 5 10 15 20 25

Walk time (minutes)

Pro

babi

lity

�

�

�

�

Interchange requiredFree parking available at workManagerial/professional job

4

Interchange requiredFree parking available at workNon-managerial/professional job

3

No interchange requiredFree parking not available at workNon-managerial/professional job

2

No interchange requiredFree parking not available at workManagerial/professional job

1


Plus projects


Plus ProjectSustainable Lifestyles


More later!

• Dr Carol Dair will speak next about this project aiming to establish whether ‘sustainable’development schemes actually lead to sustainable behaviour and lifestyles


Plus ProjectValuing Open Space


Valuing open space

3

3.5

4

4.5

1.8 2 2.2 2.4 2.6 2.8 3

log10 Plant species richness

Ref

lect

ion

2.5

3

3.5

4

4.5

1.8 2 2.2 2.4 2.6 2.8 3

log10 Plant species richness

Dis

tinc

t Ide

ntit

y


0

2

4

6

8

10

12

14

��

Valuing open space

Breeding birds

Native plants

Num

ber o

f spe

cies

Socio-economic MOSAIC group

0

1

2

3

4

5

6

7

8

9

��


Plus ProjectUrbanising Suburbia


Proposals


Proposals


Proposals


Proposals


Proposals


Towards integration


Towards integration

• How far has CityForm answered its original question?

• How do the results integrate?

• Huge number of extensive data sets

• No ‘simple’ story emerges

• More analysis possible– e.g. density

Valuing Open Space

Urbanising Suburbia

CoreSustainable Urban Form

Urban Form

TransportEnvironmental

EconomicSocial

Sustainable Urban

Behaviour & Lifestyles


Common knowledge?

• Theory, guidance, policy, practice– High density built form– Mixture of uses– Urban form is ‘contained’– Diverse, in terms of social and economic

activities

• So, how far is density a key to achieving sustainable urban form?


Case study densities

80706050403020

Dwellings/hectare – net residential density

28 47 54

33 57 73

Outer

In between

UK average UK ‘target’


Density (– illustrative examples)

Low High

Environmental – e.g. wildlife number of species

Low High

Low High

Low High

Social – e.g. satisfaction with home; social interaction

Economic – e.g. increase in population density; increase in retail trips

Transport – e.g. distance travelled increases


Urban form and density

• How important is density?– Not in most significant

correlations– Overall gross and net

density, and dwellings/ha appear as 25th, 30th and 47th of the variables associated with urban form measures

– Social factors, household type, dwelling type, open space, etc. seem more important


Sustainable urban form

• “For every problem there is a solution that is simple, neat …. and wrong” (H L Mencken)

• Sustainable urban form is complex, and ‘solutions’ are equally complex

• CityForm measured many of these tricky sustainability factors and thus has a greater understanding of the relationships between them

• Such an understanding enables more rational trade-offs to be made

• It does not permit easy assumptions about urban sustainability, or the propagation of simple ‘rules’ or myths


Outputs

• Integrated analysis of relationships to urban form– Book ‘Dimensions of the Sustainable City’

(due spring 2008)

– Journal articles (many already, and many in press, or to come)

– Conference papers and presentations internationally (key conferences in UK, USA, Netherlands, Finland, India, Thailand, Malaysia, Japan, UAE, New Zealand, etc.)

– Website (www.city-form.org ongoing)


CityForm - the future?

• Important data sets, and potential a great deal of further analysis

• Providing evidence-based knowledge of what sustainable urban form reallymeans

• Understanding and research needed at different scales – regional, and neighbourhood

• Urban contexts and cultures outside the UK


Thank you!

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