1.3. Mobility Corridor

Aus Pattern Language Wiki

In a Polycentric Region, develop proper high-speed connections between the centers of the region as well as to other regions.


03 01 Mobility Corridor.jpg


Problem-statement: There is a need for corridors that allow high-speed vehicular movement within and between cities. This need extends into the hearts of the cities. But these structures must not be allowed to sever and destroy the tissue of the city.


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Discussion:: Few structures have been more damaging to modern cities than freeways. Yet the solution of creating freeway bypasses on the outskirts of cities is equally disastrous — sapping the centers of commercial movement and activity, and at the same time generating new sprawling zones at the edges.


This is not a unique problem of the automobile age. Railways can be no less destructive of urban areas, and so can canals, rivers and other structures — in fact, any structure that significantly interrupts the connectivity and flow of pedestrians is likely to be problematic. But there are excellent examples of cities that have managed this problem, by separating the grades of the mobility corridors, and by creating a continuous fabric of connections across them. Examples can be seen in London, Paris, and many other mature cities.


03 02 Mobility Corridor.jpeg
Grade-separated mobility corridor in Paris: Place de l’Europe over a railway line.


The issue is not whether a mobility corridor is present, but whether the urban fabric surrounding it remains intact. This must be done carefully, maintaining a continuous, tight fabric with minimal intrusion of noise, emissions, and visual disorder. Examples like Place de l’Europe in Paris demonstrate the value of ample vegetation, fences and other screening devices. Some cities have simply taken their mobility corridors underground, like Oslo. Some cities bring buildings across the bridging structures, like the Ponte Vecchio in Florence.¹


One problem for many cities is the cost of excavation and retaining structures. One strategy to minimize this cost is a “balanced cut and fill” grade change, rising gently in the urban fabric to the edge of the mobility corridor, and then cut more deeply to accommodate travel lanes at a lower grade. A related strategy is to utilize existing natural watershed grade changes, taking care to avoid water pollution from vehicle emissions and other toxic runoff. Because of the cost of excavation, many cities in recent decades have chosen the easier alternative, which is to raise highways and heavy transport tracks above the pedestrian urban fabric. But the evidence shows that there is a profoundly negative impact of such solutions on the urban life underneath them.²


Of course, it must be stressed that “mobility” is not just about high speed transportation, but about integrated mobility across multiple modes (see Walkable Multi-Mobility, 2.1). A coordinated strategy is needed to keep a balanced and integrated approach to mobility.³


Therefore:

Do not push freeways, railways and other destructive activities to the edges of the city. Instead, find ways to integrate them into the urban fabric with minimal disruption, using careful grade-separating strategies. Assure that the streets above are continuous, walkable, and as protected as possible from negative impacts like noise and emissions. Plan for at least two major mobility corridors crossing each large urban area, and connecting to others.



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Mobility Corridor
Mobility Corridor


Integrate mobility corridors into the network, maintaining a 400M Through Street Network across all interruptions, providing bridges and other connections…




For a discussion of this concept in relation to urban mobility networks, see Mehaffy M.W., Porta, S., Rofè, Y. and Salingaros, N. (2010), Urban nuclei and the geometry of streets: The ‘emergent neighbourhoods’ model. Urban Design International, 15(1), 22-46.


² The damaging effects of such structures has been discussed extensively, and perhaps most notably by Jane Jacobs in The Death and Life of Great American Cities (1961, New York: Random House). She referred to the consequences as “galloping gangrene.”


³ Additional resources on this point include the World Resources Institute Sustainable Mobility Strategies, http://wrirosscities.org/sites/default/files/WRR_Transport.pdf. Among their recommendations: 1) Optimize efficiency: Support planning and implementation of higher fuel and vehicle efficiency standards and lower energy consumption and emissions from the transport sector through engagement and research. 2) Electrify fuels: Support adoption of electric vehicles and the transition to electrified transport systems through localized research and direct engagement with stakeholders from multiple sectors. 3) Integrate systems: Support implementation and management of integrated transport systems through directly influencing the planning and implementation of urban transport systems and publishing high-quality research. 4) Shift and align funding and policy: Build capacity for sustainable transport through research, direct technical guidance, policy recommendations, and stakeholder engagement with the public, private, civil society, and donor communities.


An additional resource is the European Commission’s “Green City Tool” on mobility: https://webgate.ec.europa.eu/greencitytool/topic/mobility/guidance.



Mehaffy, M. et al. (2020). MOBILITY CORRIDOR (pattern). In A New Pattern Language for Growing Regions. The Dalles: Sustasis Press. Available at https://pattern-language.wiki/.../Mobility_Corridor



SECTION I:

PATTERNS OF SCALE


1. REGIONAL PATTERNS

Define the large-scale spatial organization…

1.1. POLYCENTRIC REGION

1.2. BLUE-GREEN NETWORK

1.3. MOBILITY CORRIDOR

1.4. 400M THROUGH STREET NETWORK

2. URBAN PATTERNS

Establish essential urban characteristics…

2.1. WALKABLE MULTI-MOBILITY

2.2. LEVEL CITY

2.3. PUBLIC SPACE SYSTEM

2.4. BIOPHILIC URBANISM

3. STREET PATTERNS

Identify and allocate street types…

3.1. URBAN GREENWAY

3.2. MULTI-WAY BOULEVARD

3.3. AVENUE

3.4. SHARED SPACE LANE

4. NEIGHBORHOOD PATTERNS

Define neighborhood-scale elements…

4.1. STREET AS CENTER

4.2. PEDESTRIAN SANCTUARY

4.3. NEIGHBORHOOD SQUARE

4.4. NEIGHBORHOOD PARK

5. SPECIAL USE PATTERNS

Integrate unique urban elements with care…

5.1. SCHOOL CAMPUS

5.2. MARKET CENTER

5.3. INDUSTRIAL AREA

5.4. HOSPITAL

6. PUBLIC SPACE PATTERNS

Establish the character of the crucial public realm…

6.1. PLACE NETWORK

6.2. WALKABLE STREETSCAPE

6.3. MOVABLE SEATING

6.4. CAPILLARY PATHWAY

7. BLOCK AND PLOT PATTERNS

Lay out the detailed structure of property lines…

7.1. SMALL BLOCKS

7.2. PERIMETER BLOCK

7.3. SMALL PLOTS

7.4. MID-BLOCK ALLEY

8. STREETSCAPE PATTERNS

Configure the street as a welcoming place…

8.1. STREET AS ROOM

8.2. TERMINATED VISTA

8.3. STREET TREES

8.4. STREET FURNISHINGS

9. BUILDING PATTERNS

Lay out appropriate urban buildings…

9.1. PERIMETER BUILDING

9.2. ARCADE BUILDING

9.3. COURTYARD BUILDING

9.4. ROW BUILDING

10. BUILDING EDGE PATTERNS

Create interior and exterior connectivity…

10.1. INDOOR-OUTDOOR AMBIGUITY

10.2. CIRCULATION NETWORK

10.3. LAYERED ZONES

10.4. PASSAGEWAY VIEW



SECTION II:

PATTERNS OF MULTIPLE SCALE


11. GEOMETRIC PATTERNS

Build in coherent geometries at all scales…

11.1. LOCAL SYMMETRY

11.2. SMALL GROUPS OF ELEMENTS

11.3. FRACTAL PATTERN

11.4. FRAMING

12. AFFORDANCE PATTERNS

Build in user capacity to shape the environment…

12.1. HANDLES

12.2. CO-PRODUCTION

12.3. FRIENDLY SURFACES

12.4. MALLEABILITY

13. RETROFIT PATTERNS

Revitalize and improve existing urban assets …

13.1. SLUM UPGRADE

13.2. SPRAWL RETROFIT

13.3. URBAN REGENERATION

13.4. URBAN CONSOLIDATION

14. INFORMAL GROWTH PATTERNS

Accommodate “bottom-up” urban growth…

14.1. LAND TENURE

14.2. UTILITIES FIRST

14.3. DATA WITH THE PEOPLE

14.4. INCREMENTAL SELF-BUILD

15. CONSTRUCTION PATTERNS

Use the building process to enrich the result…

15.1. DESIGN-BUILD ADAPTATION

15.2. HUMAN-SCALE DETAIL

15.3. CONSTRUCTION ORNAMENT

15.4. COMPLEX MATERIALS



SECTION III:

PATTERNS OF PROCESS


16. IMPLEMENTATION TOOL PATTERNS

Use tools to achieve successful results…

16.1. FORM-BASED CODE

16.2. ENTITLEMENT STREAMLINING

16.3. NEIGHBORHOOD PLANNING CENTER

16.4. COMMUNITY MOCKUP

17. PROJECT ECONOMICS PATTERNS

Create flows of money that support urban quality…

17.1. TAX-INCREMENT FINANCING

17.2. LAND VALUE CAPTURE

17.3. EXTERNALITY VALUATION

17.4. ECONOMIES OF PLACE AND DIFFERENTIATION

18. PLACE GOVERNANCE PATTERNS

Processes for making and managing places…

18.1. SUBSIDIARITY

18.2. POLYCENTRIC GOVERNANCE

18.3. PUBLIC-PRIVATE PLACE MANAGEMENT

18.4. INFORMAL STEWARDSHIP

19. AFFORDABILITY PATTERNS

Build in affordability for all incomes…

19.1. INTEGRATED AFFORDABILITY

19.2. COMMUNITY LAND TRUST

19.3. MULTI-FAMILY INFILL

19.4. SPECULATION TAX

20. NEW TECHNOLOGY PATTERNS

Integrate new systems without damaging old ones…

20.1. SMART AV SYSTEM

20.2. RESPONSIVE TRANSPORTATION NETWORK COMPANY

20.3. AUGMENTED REALITY DESIGN

20.4. CITIZEN DATA