sustainability and transportation

Using a Sustainable Solution Space Approach

to Develop a Vision of Sustainable Accessibility

in a Low-Income Community in Phoenix, Arizona

Leonard Machler1 and Aaron Golub21School of Community and Regional Planning, University of British Columbia,Vancouver, British Columbia2School of Geographical Sciences and Urban Planning and School ofSustainability, Arizona State University, Tempe, Arizona

ABSTRACT

The sustainability challenges posed by Americas automobile-based transportsystem demand a transition toward more accessible urban areas. Accessibilityplanning at the neighborhood scale involves improving both non-automobilemobility and the range of services offered within a community. Reflecting the com-plex system dynamics influencing neighborhood travel behavior and the contextof local access needs, we employ the Sustainability Solution Space (SSP) methodto envision a sustainable state of transportation accessibility for the Sky Harborneighborhood of central Phoenix, Arizona. This case study explores the suitabilityof the SSP methodology for sustainable visioning exercises, recommending its usefor participatory transportation planning studies.Key Words: accessibility, collaborative research, sustainable transport planning

ACCESSIBILITY AS A SUSTAINABILITY PROBLEM

Planning urban transport needs around the private automobile presents manysignificant challenges to sustainability. From an environmental perspective, auto-mobile travel has contributed to greenhouse-gas related climate change, airpollution-attributed adverse health problems, and ecosystem degradation fromthe construction of highways and automobile-oriented suburban sprawl (Johnson2001; Black 2005). Americas reliance on private automobile transport for urbanmobility also has significant social ramifications (Boschmann and Kwan 2008).

Received 19 November 2010; revised 20 June 2011; accepted 11 July 2011.Address correspondence to Leonard Machler, School of Community and RegionalPlanning, 433-6333 University of British Columbia, Memorial Road, Vancouver, BritishColumbia, V6T 1Z2 Canada. E-mail: [email protected]

International Journal of Sustainable Transportation, 6:298319, 2012Copyright # Taylor & Francis Group, LLCISSN: 1556-8318 print=1556-8334 onlineDOI: 10.1080/15568318.2011.605210

298

Cars were responsible for over 37,000 traffic fatalities in the U.S. in 2005, many ofthem pedestrians (NHTSA 2008). Worldwide, automobile accidents are also theleading killer of youth aged 1529 (WHO 2009), disproportionately burdeningyounger generations. Due to the expense of owning and maintaining private auto-mobiles, the proportion of the American household budget that is devoted totransportation jumped from 4.5% in 1915 to 19% in 2002 (Whitt and Yago 1985;Pisarski 2006) while in the neighborhood studied in this article, the Sky HarborNeighborhood (SHN) of Phoenix, spending up to 50% of a familys discretionarybudget on transportation was not uncommon. The cost of car ownership andoperation also precludes poorer inner city residents from accessing places ofemployment and education that are often located on the urban periphery (Wilson1996; Garrett and Taylor 1999). Additionally, highways have historically beenrouted through poorer urban neighborhoods (Bullard, Johnson, and Torres 2004).

Public transit is often touted as a means of solving mobility issues in a moresustainable fashion than through the use of private automobiles. While more pref-erable to a car-based system by certain sustainability metrics (Kenworthy 2006),public transit still relies heavily on expensive capital infrastructure provision inthe form of specialized vehicles and fixed guideways. The high cost and routinemaintenance required for a complex socio-technical system such as a regionalpublic transit authority leaves legacy costs for future generations. The MaricopaAssociation of Governments (LKC Consulting 2003), metropolitan Phoenixsregional government, estimated that maintaining existing transit service withinthe countynot including new infrastructure constructionwould cost $5.2 bil-lion between 20112020 and jump to $6.6 billion between (20212030)a 166%increase over the previous decade, 20022010. While public transit offers a higherdegree of social empowerment for marginalized people over a private automobiletransport system, building public transit to enhance mobility still requires residentsto depend on a transit line to access activities in much the same way as they wouldotherwise rely on a car. The reliance on a fixed transit line, fares and a schedulethat individual people have little control over affects the range of activities thatare available to them. If sustainable development is widely acknowledged to involvemeeting the needs of present generations without compromising the ability offuture generations to meet their own needs (WCED 1987), mobility-based strate-gies are resolutely unsustainable: they introduce many social and economic prob-lems to current generations while placing a heavy social and economic burden onfuture generations.

Instead of emphasizing mobility strategies that seek to increase movement, manytransport scholars advocate accessibility strategies that improve the ability ofresidents to reach the destinations that they previously had to travel for (Handy2005; LeClercq and Bertolini 2003; Cervero 2001). Most people, after all, donot travel for the sake of traveling, but to access distant activities and services; asKevin Krizek (2005) bluntly puts it, travel occurs because someone wants to dosomething somewhere else. Rather than focusing on the means of transportas mobility does, accessibility focuses on the ends of transport (Handy 2005).In this article, we suggest that a truly sustainable transportation accessibility strategywould seek to maximize the number of available activities and services that existwithin walking distance of the majority of a neighborhoods residents.

Sustainable Accessibility

International Journal of Sustainable Transportation Vol. 6, No. 5, 2012 299

THE ATTRIBUTES OF SUSTAINABLE ACCESSIBILITY

While the detrimental effects of automobile-based mobility planning is well stud-ied, comparatively less research is spent on characterizingor envisioningwhat aneighborhood with a sustainable level of transportation access might look like.While planning initiatives such as the New Urbanism and Smart Growthmovementshave proposed built form improvements that might improve facets of transpor-tation access and livability in a neighborhood, this variety of envisioning has notyet considered the full nature of our automobile-based mobility system, with its mul-tiple socio-economic and systemic drivers and responses. Most transport visioningprojects have also not outlined how their selected improvements might interferewith other aspects of proper neighborhood functioning, especially if the welfareof a neighborhood is to be considered as an integrated system. When single orunconnected metrics are used to plan improvements to complex problems, inevi-tably other features that are not integrated into those models will be compromised(cf. Robinson 2003). Because of the unique travel needs and activities identified bydifferent communities, defining accessibility strategies is a highly context-dependent exercise (Bertolini, LeClercq, and Kapoen 2005). Eliciting the inputof local residents to specify their access needs is crucial and profits immensely fromincorporating experience-based knowledge from the citizens that stand to inheritthe plan. Ideally, local citizens should be able to manage and control their accessi-bility strategies with the help of planners and other governance (cf. Arnstein 1969).Additionally, choosing a neighborhood or community scale to craft an accessibilityplan is not accidental: integrated knowledge production begins at levels where indi-viduals can hold personal attachment or ownership (Gibbs 1993). Finally, themicro-scaled community level is the niche where transitions are most likely to occur(Loorbach 2007). It is in this spirit of micro-scaled, democratically-negotiatedtransition that an accessibility paradigm may begin to slowly replace existingautomobile-dependent mobility patterns.

The objective of this research study is to determine a holistic vision for neighbor-hood transportation access using a method that incorporates the largest possiblerange of options that can be taken without compromising the performance ofneighborhood functioning as a whole. Additionally, we were interested in incorpor-ating the participation of local citizens throughout the research process itself. Inthis article, we present a case study of the application of such a method, calledthe Sustainability Solution Space (SSP; Wiek and Binder 2005) to a particularneighborhood. In contrast to other approaches, the SSP approach attempts specifi-cally to understand the multiple characteristics of a desired neighborhood, thesystemic interactions between those characteristics and, by understanding the syner-gies and conflicts between characteristics, to create a balanced range of solutionsthat incorporate all of those characteristics. We apply this method to the problemof transportation accessibility in a low-income neighborhood in Phoenix, Arizona.First, we cover some background material on visions of sustainable accessibilityand the SSP method. Then, we proceed through the method for our case studyneighborhood, eventually revealing the SSP for its accessibility needs. We end withsome discussion of this method and implications for further research, as this is thefirst known case of applying these methods to a transportation problem.

L. Machler and A. Golub

300 International Journal of Sustainable Transportation Vol. 6, No. 5, 2012

THE SUSTAINABILITY SOLUTION SPACE METHOD

The SSP method was selected to collaboratively envision a sustainable state ofaccessibility for the Sky Harbor neighborhood of Central Phoenix. The SSP is anindicator-based assessment approach that uses scenario analysis methods (Scholzand Tietje 2002) to define an action space (Potschin and Haines-Young 2008)where a sustainable state may be achieved without compromising the integrity ofthe system. While the SSP has its roots in formative scenario analysis techniques,its commitment to enabling social change (i.e., envisioning a sustainable state)through the combination of systemic methods, models and participatory problemstructuring techniques echoes the discipline of community operational research(Jackson 2004; Midgely and Ochoa-Arias 2004).

The SSP methodology used in an urban assessment case study in Thalwil,Switzerland (Wiek et al. Forthcoming) served as the template for this case study. Itshould be emphasized that the SSPmethod yields an outcome statea vision for a sus-tainable solutionand does not address strategies and tactics for reaching that state.Howeveras we explore in the Discussion sectionsome of the actions needed toimplement the vision were simultaneously outlined in the workshop with stakeholders.

THE SKY HARBOR NEIGHBORHOOD

The case study community in central Phoenix is bounded by 24th and 38thStreets on the east and west, by Van Buren Avenue to the south, and by the Loop202 freeway to the north (see Figure 1). The neighborhood, known informally asthe Sky Harbor neighborhood (SHN), is a majority Hispanic (U.S. Bureau ofthe Census 2000), working-class community in central Phoenix that suffers fromnumerous environmental-justice and transport-access problems. Among the inequi-ties, the community has a disproportionately high incidence of pedestrian trafficfatalities compared to the rest of the City of Phoenix, a poor physical environmentthat discourages walking, and an absence of parks or green space (Cutts et al. 2009).In an informal conversation, stakeholders from the area specifically mentioned thelack of sidewalks and the difficulty encountered in petitioning the city to buildthem. Because of the relatively poor public transit options and low rates ofcar-ownership, carpooling is a more prevalent mode for commuting to work thanin the rest of Metropolitan Phoenix, with 24.1% of all commutes handled by2- or 3-person carpool (U.S. Bureau of the Census 2000). Based on discussionswith neighborhood residents, almost all recreational travel, including those fewtrips which take place within the neighborhood, is still done by automobile.

DETERMINING THE SSP

The research method used in this study utilizes various inputs to create the SSP.A SSP is developed in several steps listed here, and explained in more detail after.

1. Indicator selection. A suite of indicators characterizing both the systemic natureof transportation access and the ability to provide access in the neighborhoodwere developed and tested against three sustainability indicator paradigms.The choice of indicators was also elicited with the help of resident input.



2. Relationships between indicators. The interaction and influence betweenindicators was assessed using impact analysis methods (Scholz and Tietje 2002).

3. Indicator thresholds. Four specific target, or threshold, levels were developedfor each indicator: Level 1 representing a minimally-acceptable state; level 4representing the optimum performance of that indicator, and levels 2 and 3representing intermediate states.

4. Consistency analysis. A consistency analysis tested each of the four thresholdlevels for indicators against those target ranges from other indicators to deter-mine what possible threshold pairings were compatible.

5. SSP formation. The space bounded by the highest and lowest range of all poss-ible consistent scenarios is the Sustainable Solution Space (SSP). Operatingwithin this space suggests the realization of a vision where all aspects of accessi-bility provision have been perfectly balanced.

At the core of the SSP methods is the use of indicators (Wiek and Binder 2005).The indicators allow us to characterize accessibility in the neighborhood as an inter-connected system, measure progress towards target outcomes, and locate wherecompromises between those targets occur because of incompatible outcomes. Oncethe indicators are chosen, we need to determine how they interact with one another:do improvements in one indicator compromise the performance of others? Forexample, Household Transportation Budget (see Table 1) is an indicator which

Figure 1. The Sky Harbor neighborhood in relation to Phoenix.



would be measured as the share of the household budget spent on transportation.Affordability may interact positively with other indicators, such as a povertyindicator; likewise, the number of basic services located within a reasonable walkingdistance (represented by the indicator Access to Services) would also lower a house-holds discretionary spending on transportation. We also need to determine whatare acceptable states and ideal states for each indicator. Acceptable states would rep-resent a minimally acceptable solution that still represents an improvement over thestatus quo, while ideal states would represent the communitys agreed-upon bestcase scenario. Of course, not all outcomes for all indicators can be best case. Provid-ing free transportation for all residents might be considered a most desirable out-come, but one that is inconsistent with other neighborhood goals because asignificant amount of resources would have to be withdrawn from other initiatives(i.e., the ideal performance of all other indicators would be compromised). Like-wise, filling all vacant lots with housing for improved density would not be feasiblewithout sacrificing plans for adding parks or retail that might be planned for thesame land. Using the threshold levels and the relationships between indicators,an algorithm is used to determine consistency between indicator levels for all poss-ible indicator pairs (Wiek and Binder 2005). The consistent pairings for all indica-tors taken in the aggregate becomes the SSP, and demarcates the range of actionsthat can be taken such that the performance of a factor that contributes to transportaccessibility in the SHN (represented by an indicator) does not compromise thefunctioning of all the other identified factors that contribute to neighborhoodtransport accessibility (i.e., all other indicators). During each step of the researchprocess, the input of stakeholderseither the resident group representing theneighborhood, or the chief planner for the City of Phoenixwas sought.

Table 1. Neighborhood-level and system-level indicators.

Indicator nameDesignation(for Figure 2)

Neighborhood-levelindicators

Density NL-1Sidewalks and Walkability NL-2Air Pollution NL-3Access to Parks and Recreational Facilities NL-4Access to Services NL-5Access to Good Jobs NL-6Household Transportation Budget NL-7Urban Heat Island NL-8Transport Projects City NL-9Perceptions of Safety NL-10

System-levelindicators

Urban Design and Planning Protocols SL-1Internalization of Automobile-based costs SL-2City Revenue Sources SL-3Transportation Mode Share SL-4Adverse Health Effects SL-5Poverty Levels SL-6Civil Society and Intact Communities SL-7



Indicator Selection

The full set of indicators used for this project included neighborhood accessi-bility indicators that were collaboratively defined with a stakeholder group ofSHN residents, and a further set of seven external indicators that representupstream drivers imposed upon the neighborhood and broad, downstream societaleffects. These external indicators were developed with the help of a planningofficial in the City of Phoenix and are meant to adequately describe the currentand future transportation regime as a more comprehensive system than just thoseissues in the Sky Harbor Neighborhood.

Starting from an initial set of developed indicators, a final set was selectedby filtering each indicator through a normative scoring mechanism based onthree separate sustainability and systems principles. Bossels (1999) orientorsapproach to sustainable indicator selection was used to determine the applicabilityof the indicators to system integrity; Gibsons (2006) core generic criteria for sus-tainability assessments were employed to determine whether the indicators suffi-ciently described the sustainable functioning of the system, while Gudmundssonand Hojer (1996) have developed principles which are meant to guide the devel-opment of sustainable transport practices. Each indicator was evaluated againstthese principles by the researchers and assigned a score based on how many ofthe criteria within each set of principles were met. Indicator scores were aggre-gated, and those that accounted for at least 50% of the criteria were retained forfurther use. In the end, ten neighborhood-level and seven system-level indicatorswere selected using the indicator scoring mechanisms. Table 1 displays theneighborhood-level and system-level indicators selected for use in our study. Formore information on the scoring process and the definitions of the indicators,see (Machler 2010, 1214).

Impact Analysis

One of the objectives of using indicators in an SSP is to model current systembehavior. An impact analysis (Scholz and Tietje 2002) was performed to create amodel for system behavior and to describe how the various barriers interacted withone another to block the successful implementation of transport access in theSHN. Impact analyses may be used in future implementation strategies, to identifyissue areas that exhibit more connections to other areas and thus present greaterdifficulties in attempting to circumvent.

The impact analysis was performed using a structured qualitative approach,assigning influence scores from one indicator on another using an impact matrix(Vester 1988). To support the decisions, we used general insights derived fromtransportation planning and environmental justice literature and supplementedour analysis with local knowledge from SHN residents.

Using the impact analysis software SystAIM, each indicators influence on allremaining indicators was plotted in a system grid (see Figure 2 below) that aggre-gates the impact strengths for each indicator on a Cartesian grid according to theirsystem impact (Vester 1988; Scholz and Tietje 2002). SystAIM adds up the sum ofthe rows and columns of an impact matrix to calculate the activity (the numberof impacts an indicator has on other indicators) and passivity (the number of



indicators that impact that indicator) scores, respectively. The axes of the systemgrid are categorized by their activity and passivity and plotted in four quadrants:

1. An active quadrant, in the upper left-hand corner of the grid, where indicatorsimpact a majority of all other indicators, but are not impacted by a majority ofothers. Active indicators may be considered to be upstream drivers of systemoutcomes (Ravetz 2001).

2. An ambivalent quadrant, in the upper right-hand corner, where indicators areimpacted by themajority of all other indicators and also impact amajority of others

3. A passive quadrant, in the lower right-hand corner, where the indicator is impac-ted by the majority of other indicators, but does not impact a majority of all otherindicators. Passive indicators may be considered to represent downstreamoutcomes of system drivers (Ravetz 2001).

4. A buffering quadrant, in the bottom left-hand corner, where the indicatorneither impacts the majority of other indicators nor is it impacted by a majorityof other indicators.

The system grid reveals that the majority of indicators are ambivalent, activeor passive and only one indicatorPoverty Levelshas less than a majority of

Figure 2. System grid.



indicators either impacting it or being impacted by it. The top-down impact analysisconfirms that the indicators selected are tightly coupled in a system characterized bymany interactions. Not surprisingly, upstream system-level indicators such as UrbanPlanning and Design Protocols, the Internalization of Automobile-based Costs(IABC) and City Revenue Sources possess high activities since their performancein the systems framework (see Figure 2) directly impacts the functioning of down-stream variables, both at the neighborhood and city=regional level. Similarly, indica-tors that are meant to map downstream effects (e.g., Adverse Health Effects, CivilSociety and Intact Communities) are highly passive since they are heavily impactedby other indicators and thus serve as bellwethers for proper upstream system func-tioning. All neighborhood-level indicators are clustered in the center of the systemgrid, being both downstream from upstream-level system indicators but also driversof long-term societal effects represented by downstream system indicators. All tenindicators within the neighborhood-level analysis have some bearing on one another;no neighborhood-level indicator is isolated from any other by impact. The impactanalysis confirms the highly interconnected nature of the indicators and, by exten-sion, a highly interconnected characterization of neighborhood accessibility.

Using Local Knowledge

Given their knowledge of the neighborhood, SHN residents were asked to analyzethe relationships between the ten neighborhood-level indicators in a separate analy-sis. Residents were asked to draw an arrow between indicators that they perceived tohave a direct impact (the direction of the arrow being the direction of influence) onthe other indicator. The impact strength of an indicator was represented by thenumber of stakeholders who drew a linkage between two indicators (Figure 3)

The neighborhood residents considered three indicators to be neither influencingnor influential: Household Transportation Budget, Access to Good Jobs, and UrbanHeat Island (UHI). The presence of three buffering indicators was a noticeabledeviation from the researchers impact analysis, in which only one, weakly bufferingindicator (out of seventeen) was revealed. When queried, stakeholders respondedthat UHI was probably not a considerable factor, although in conversation they didacknowledge that elevated temperatures would likely lead to fewer people ridingbikes. The researchers top-down analysis demonstrated that Access to Good Jobswas impacted by factors such as Density and Perceptions of Safety, empirically-supported by attributes such as the willingness of employers to locate to potentiallyunsafe neighborhoods, particularly neighborhoods of color (Wilson 1996; Tillyet al. 2001) and because higher density neighborhoods often tend to be mixed-useareas with a greater access to job opportunities (Cervero and Kockelman 1997).

Two particular indicator impacts resonated very powerfully with neighborhoodresidents: the influence of Sidewalks and Walkability on Perceptions of Safety, aswell as the opposite impactthat of safety perceptions on walkabilitywas ident-ified by a majority of residents participating in the meeting. When queried, stake-holders unanimously declared that the neighborhood, or at least part of theneighborhood, was unsafe for walking at certain times of the day, and that their fearof crime was a significant barrier to overcoming their use of automobiles. In con-trast, the researchers rationalized that the areas poor physical and aesthetic designfor walkability was the a priori condition for heightening residents perceptions of



the areas insecurity (Painter 1996). The researchers therefore saw walkability (as adesign concept) as influencing perceptions of safety, rather than the other wayaround. This difference between the residents and the researchers perspectiveswas reconciled during the negotiations that defined indicator threshold levels; resi-dents were encouraged to define improvements to walkability (see Table 2) thataddressed the issue of safety, and consider ways of improving safety that would fostermore pedestrian activity. The results of both the resident-led and researchersimpact analyses suggest that transportation accessibility is a tightly-coupled system,incorporating many socio-economic considerations that are not typically includedin transportation assessments, including: the impacts of crime and safety percep-tions and the form of revenue-generation a city government relies on to providepublic services. A proper vision for transportation access will need to account forall these facets and properly understand how they interact as an integrated system.

Figure 3. Impact analysis exercise for stakeholders. Note. Stakeholders drew

arrows between indicators, showing the directionality of impact. In this

example, improving sidewalks and walkability is considered to affect

access to nearby services, recreational facilities, the respondents per-

ceptions of safety, and air pollution. Improving sidewalks and walkabil-

ity is, however, influenced by the type of transport projects that the

city spends its money on.



Table

2.

Selected

neigh

borhood-levelindicators

andtheirthreshold

levels.

Indicatornam

eLevel

1(M

inim

um

acceptable

state)

Level

2Level

3Level

4(O

ptimal

state)

Den

sity

25%

ofvacantlotsfilled

withhousing.

50%

ofvacantlotsfilled

withhousing.

75%

ofvacantlotsfilled

withhousing.

100%

ofvacantlotsfilled

withhousing.

Sidew

alks

and

Walkability

Addstreetligh

tsan

dsidew

alks

tohighest

priority

areas.

Level

1ad

ditionof

crosswalkan

dlower

priority

ligh

tingprojects.

Level

2lowpriority

sidew

alkim

provemen

ts.

Level

3bikelanes

toincludeall

improvemen

ts.

Accessto

Parks

and

Recreational

Facilities

Park#1:

Large

centrally-lo

catedfacility.

Park#1second,basic

parkoneasternsideof

neigh

borhood.

Parks#1,

2Boysan

dGirlsclub(Park#3)

across

thestreet

from

Park#1.

Parks#1,

2,3Parkin

the

NEcorner

ofthe

neigh

borhood.

Accessto

Services

Buildadrugstore=grocery

store,an

dYM

CA.

Level

1garden

on

Adam

s.Level

2movietheater,

discountdep

artm

ent

store

andban

kon

WashingtonSt.

Level

3Get

ridofvacant

lotsalongVan

Buren;

replace

withbikeshop

andcafe.

Household

Transportation

Budget

Maxim

um

20%

ofa

householdsincomeis

spen

tontran

sportation.

Maxim

um

16%

ofa

householdsincomeis

spen

tontran

sportation.

Maxim

um

12%

ofa

householdsincomeis

spen

tontran

sportation.

Maxim

um

8%ofa

householdsincomeis

spen

tontran

sportation.


Indicator Threshold Determination

The ideal (level 4) and minimally-acceptable (level 1) states for the 10neighborhood-level indicators were collaboratively decided by the researchersand SHN residents. Thresholds for the 2 intermediate indicators (Levels 2 and 3)were defined independently by the researchers after the meeting with residents.All four threshold levels for the 7 external system indicators were determined pri-marily by the researchers with support from the chief city planner of the City ofPhoenix. The indicator threshold levels for the neighborhood-level indicators areshown in Table 2; the threshold levels for system indicators are shown in Table 3.

Several strategies were employed in the SHN workshop to assist in the develop-ment of indicator threshold levels for the vision. For certain indicatorsparticularly those where a vision could be operationalized in a tangible, built-formimprovementsuccessive indicator thresholds are assigned by providing incre-mentally larger quantities of a desired end product. For example, the thresholdsfor Density (refer to Table 2) advance sequentially from filling one-quarter ofthe neighborhoods vacant lots with houses (Level 1minimum sustainable state)to filling all available lots with housing (Level 4). Ensuring a linear progression ofone sustainable amenity informed the threshold determination for severalindicators, both at the neighborhood and system level, including: HouseholdTransportation Budget, Transportation Mode Share, Adverse Health Effects,Poverty Levels and Civil Society and Intact Communities.

Other built form indicators, such as Sidewalks andWalkability, Access to Services,Access to Parks and Recreational Facilities, Urban Heat Island and Perceptions ofSafety involved a high degree of collaboration and local knowledge sharing, with resi-dents informing the meeting facilitatorswith the help of neighborhood mapstheir locational preferences for infrastructure improvements (e.g., parks, retailoutlets, street lighting, sidewalk and bicycle lanes). In addition, stakeholders also dis-cussed the type and quality of amenities to be provided. At the Perceptions of Safetytable, residents used themaps as an opportunity to locate pressing local issues relatingto crime, supplying the facilitators with a rich oral history of crime problems in theneighborhood and stimulating a lively discussion about community policing strate-gies. These discussions led the stakeholders and the facilitators to map a very compre-hensive and contextually-relevant vision to improve safety in the neighborhood(Machler 2010, p. 179 see Figure 5, Appendix E), and provided the stakeholders withthe opportunity to determine not just the ideal and minimum indicator target levels,but also to reveal a vision for the intermediate threshold levels as well.

Consistency Analysis

By performing a consistency analysis with the use of a consistency matrix (Scholzand Tietje 2002, 105113), we identified conflicts and incompatibilities between thethreshold levels of indicator pairs. The indicator threshold pairings that were incom-patible with one another were marked as inconsistent in the matrix and ultimatelyrejected. The compatible, or consistent, indicator threshold pairings that resultedfrom the analysis formed the range of possible indicator actions defined by the SSP.

The construction of the consistency matrix was the most labor-intensive andintellectually demanding part of this case studys research and did not lend itself



Table

3.

Selected

system

-levelindicators

andtheirthresholds.

Indicatornam

eLevel

1(M

inim

um

acceptable

state)

Level

2Level

3Level

4(O

ptimal

state)

TransportationMode

Share

80%

oftravel

isdonein

private

cars.Atleast5%

isnon-m

otorized.

70%

oftravel

isdonein

private

cars.Atleast5%

isnon-m

otorized.

60%

oftravel

isdonein

private

cars.Atleast5%

isnon-m

otorized.

50%

oftravel

isdonein

private

cars.Atleast5%

isnon-m

otorized.

PovertyLevels

Number

ofHouseholds

livingbelowpovertyline

reducedby10%

over

curren

tlevels.

Number

ofHouseholds


reducedby20%

over

curren

tlevels.

Number

ofHouseholds


reducedby30%

over

curren

tlevels.

Number

ofHouseholds


reducedby40%

over

curren

tlevels.

CivilSo

cietyan

dIntact

Communities

Thenumber

ofneigh

bors

that

averageresiden

tscaniden

tify

inasurvey

increasesby50%

over

curren

tlevels.

Thenumber

ofneigh

bors

that

averageresiden

tscaniden

tify

inasurvey

increasesby75%

over

curren

tlevels.

Thenumber

ofneigh

bors

that

averageresiden

tscaniden

tify

inasurvey

increasesby10

0%over

curren

tlevels.

Thenumber

ofneigh

bors

that

averageresiden

tscaniden

tify

inasurvey

increasesby12

5%

over

curren

tlevels.


to public involvement over the short time period we had available. Instead ofparticipating directly in the generation of the consistency matrix, the researchersperformed the consistency analysis independently and SHN residents were con-sulted whenever a conflict between two indicator threshold levels arose. If thestakeholders local knowledge differed from our own, the matter was deliberatedand a consensus was achievedoften by changing the definition of an indicatorthreshold so that a consistency was achieved. For example, a panel of residentswas queried about the redundancy of building a YMCA (See Table 2, Access toServices, Level 1) down the road from a Boys and Girls Club (Access to Parksand Recreational Facilities, Level 3). We mentioned that this redundancy wouldcost valuable resources and therefore only one of the two facilities could be feasiblebut not both. Residents argued that the two facilities served different demo-graphics, citing [anecdotally] the large numbers of both senior citizens and chil-dren in the area. In the end, a compromise was reached where the YMCA wouldbe built and a Boys and Girls Club would be housed in the same premises. As aresult, a consistency was achieved.

Sustainable Solution Space

The role of the SSP model in this case study is to describe a vision for transpor-tation access where system functioning (the various facets of a transportationaccess system are represented through the use of indicators) is perfectly balanced.As a result, the SSP defines the range of thresholdsor space for each indi-cator, in which action can be taken without encountering an inconsistency withanother indicator elsewhere. This action space can be visualized in Figure 4 as

Figure 4. Sustainability Solution Space for sustainable transportation accessi-

bility in the Sky Harbor neighborhood.



the area bounded by the outer boundary (the highest set of indicator thresholdlevels in which consistent action can take place) and the inner boundary (con-versely, the lowest set of indicator threshold levels in which a systemically-balancedvision can take place). The SSP was generated using KD consistency analysissoftware (cf. Tietje 2005), which shrank the consistency matrix by eliminatinginconsistent indicator threshold pairings.

In all but four indicatorsSidewalks and Walkability, Perceptions of Safety,Poverty Levels and Civil Society and Intact Communitiesthe ideal performanceoutcome (the ability to reach Level 4) is impossible to reconcile without encounter-ing a trade-off elsewhere. Systematic considerations of sustainable functioning inevi-tably involve compromises and recognize that adequate rather than ultimatesolutions are the ones that are feasible (Potschin and Haines-Young 2005); if theultimate solutions are described by a space that occupies the entire space withinthe outer white sections of the diagram in Figure 4, the holistically-balancedSSPthe shaded portion in Figure 4occupies only a fraction of that realm. Movingthreshold levels to more ambitious targets for certain indicators would result ininconsistencies with other indicators. For example, reaching level 4 of the Densityindicator demands that 100% of the vacant properties in the neighborhood arereplaced with housing. However, replacing all the empty lots with housing would jeo-pardize efforts to locate retail and park space on the same parcels of land. Since parkimprovements and the addition of certain services are deemed to be a higher priorityby neighborhood residents (i.e., these improvements were defined to occur at lowerthreshold levels), obtaining the highest threshold level for density is not permissible.

For certain indicators, the action space is constrained to just the lowest, or first,threshold level. Often, this is a result of overly ambitious target setting that theperformance of other indicator threshold levels cannot satisfy. For example, level1 performance for the indicator Transportation Mode Share calls for a reductionin private car use in the neighbourhood to just 80% (including carpooling) of alltrips. 90% of the population currently uses private cars for commuting purposes(U.S. Bureau of the Census 2000). Level 2 for the same indicator demands areduction in private car commuting to 70% of all trips, and a 20% reduction in auto-mobile use was considered difficult to achieve within the parameters of changeassigned for other indicators. Finally, due to the limitations of the computing powerof KD consistency analysis software, only 16 of the 17 indicators were able to beanalyzed. Urban Heat Island was abandoned due to its low influence on systemdynamics (see Figure 2) and its low priority among neighborhood residents.

Stakeholder Recruitment and Participatory Workshop Design

All steps in the research process included some element of community or outsideprofessional input from both residents of the SHN and the chief city planner ofPhoenix. The principal activitydefining the indicators and their appropriatethreshold levelstook place in two separate meetings, one held with neighborhoodresidents and one during a one-on-one meeting between the researchers and thecity planner. The recruitment of a stakeholder group that was representative ofthe neighborhood was the responsibility of the president of the Sky Harbor Neigh-borhood Association (SHNA), who would serve as the researchers main point ofoutside contact and collaboration throughout the research project. The choice



of the SHN as a case study was largely informed by consulting with a communityorganizer who was active in neighborhood activism, and had considerable ties withthe SHNA. While the researchers, the community organizer and the president ofthe SHNA were willing to support each other in their endeavors, each groups par-ticipation in the project largely depended on fulfilling personal interests. Figure 5describes the personal motivations that led the three groups to collaborate witheach other.

The researchers were largely divorced from choosing the participants of thestakeholder engagement meeting. From the perspective of the researchersinvolved, this strategy created buy in into the case study from the neighborhoodpresident, since it elevated her power position in the research process and empow-ered her to assemble a group that already had a history of successful team work. Fur-thermore, the trade-off was considered to be minor: when choosing neighborhoodstakeholders the researchers desired a good cross-section of the area over expertisein transportation issues or systems thinking. Given the novel and relatively academictopics covered in the stakeholder meeting (i.e., consideration of neighborhoodaccessibility from a systems thinking perspective), the researchers felt that recruit-ing a stakeholder group on their own terms would not have gathered a networkof participants that had more previous insights into the topic, while the benefitsof an already established group dynamic would not have been present.

The stakeholder group assembled for the meeting was representative of theneighborhoods racial demographics. Anecdotally, 11 of the 12 participants (92%)were of Hispanic descent, compared with the neighborhood, as a whole, whichwas 81%Hispanic (U.S. Bureau of the Census 2000). While accurate record-keeping

Figure 5. Stakeholder motivations for participating in study.



was not taken at the meeting, most participants seemed to be over 30 years of age,with a disproportionate number of stakeholders being 50 years of age or higher;unfortunately, this is not representative of the neighborhoods median age of 21.9years, and neglects to consider a future generation that will play a stake in a possibleaccessibility transition. While recruiting an ethnically representative sample of theneighborhood demonstrates the success of relying on an outside stakeholder forrecruitment, the inability to involve youth in the meeting was a flaw, and is con-sidered to be a weakness of many participatory research projects, in general (cf.Checkoway and Richards-Schuster 2003). Ameliorating the lack of youth represen-tation, some participants informally acknowledged that they were the parents ofyoung children; simultaneously, many of the indicator performance thresholds wereelucidated by an iterative process in which facilitators encouraged the stakeholdersto think about the welfare of future generations and also to consider the currentchildren of the neighborhood.

Preparation for the stakeholder workshop involved considering a layout for theroom that permitted the facilitators to engage the most effectively with stake-holders. Six facilitators were recruited, including the lead researcher, four membersof Arizona State Universitys School of Sustainability, and the community organizerthat had helped set up the negotiations with the stakeholder group. Working withthe researchers, the president of the SHNA arranged an evening meeting to takeplace over a period of four hours within the neighborhood. The meeting beganwith a plenary discussion in which stakeholders were encouraged to comment onthe current state of transportation accessibility in the neighborhood. Apart fromthat, most discussions, including the important work of defining indicators andtheir thresholds, was performed in small group settings, with four residents seatedaround a table staffed by two meeting facilitators. Three group tables were arrangedand between three and four indicators were arbitrarily assigned to each group. Toaccommodate participants, facilitators who spoke Spanish were paired with stake-holders who possessed language difficulties. Additionally, complex academic termswere simplified for layperson understanding. The concepts for the indicators wereaccompanied by a normatively-phrased guiding question that was meant to stimu-late discussion and lead to a community-based definition and threshold identifi-cation. For example, the indicator Access to Services was rephrased as Whatkinds of stores and services should our neighborhood have? Where should theygo? and featured photos associated with a variety of stores and services, includingbanks, grocery stores, clinics and banks. Narratives and story-telling (cf. Innes andBooher 2010) were used to stimulate discussion and ground the discussion of indi-cators and their systemic relevance in personal experience, while large maps of theneighborhood (cf. Corburn 2005) were used for residents to physically draw wherethey desired built form improvements to be located.

The design of the workshop, where the twelve participants were divided betweenthree separate tables and focused on three to four indicators each, also presented acompromise between inclusion and detail. On one hand, an opportunity wasmissed for all residents to participate in crafting thresholds for every indicator. How-ever, the discussions that took place were in more intimate settings of four people(six including the facilitators), and the arduous task of defining indicator thresh-olds was less harried when a small table debated three to four indicators rather than



all participants in the room debating up to ten. Participants often enjoyed up to anhour of discussion per indicator, and the researchers deemed the results to bemuchmore rich, descriptive and personal in the smaller group settings.

DISCUSSION

The vision crafted by the SSP employs a high degree of citizen participation,because the indicator selection and the target levels that define the vision are col-laboratively defined by neighborhood residents, a city planner and the researchers.At the same time, the SSP allows a vision to be crafted that balances the systemicconstraints present in providing access. For transportation policy and urbandecision makers, the space generated by the SSP identifies the amount of effortand type of action required to maintain a balance of accessibility requirementswithout introducing compromising factors that might impede the functioning ofthe neighborhood. By identifying which individual indicator ranges result in a con-sistent system, the SSP outlines whether more or less effort and resources arerequired in specific areas (e.g., housing, crime, household transportation budgets)to achieve sustainable transport access at the neighborhood scale.

As an urban planning tool, the SSP has demonstrated a new approach to engagingcitizens in systemic decision-making. Residentsmany of whom did not have a largeamount of formal education were involved in providing the local knowledge andhistory of transportation inequity that was necessary to tailor a vision that was contex-tually appropriate for their area. In addition, the stakeholders revealed systemicinterconnections between various facets of their transportation needs that wouldnot have been available to the researchers through traditional, empirical forms ofresearch. Sustainability science demands a perspective of the variables that mightextend beyond a single disciplinary perspective but have profound implications onsystem dynamics (Kates et al. 2001). In the study of urban transportation, single, iso-lated metrics and outcome measurements are insufficient for describing how or whypeople travel, nor to provide an adequate prescription for enhancing access to dif-ferent communities (Litman 2007), and there is a need to comprehensively accountfor the multitude of costs, benefits and interactions of the factors that influence andare influenced by urban travel (Shay and Khattak 2010). The SSP provides a methodfor reconciling the outcomes of the multitude of indicators that are needed to fullyrepresent or measure a systemic problem such as transportation access.

The opportunity to strengthen our systems understanding of the impacts ofsocietal processes, and the degree of citizen involvement in crafting a holistically-balanced vision demonstrates the power of the SSP method as a planning tool, notjust in transportation but in a variety of other disciplines.

The SSP method is not without its limitations, particularly with regard to itsdegree of contextualization, or how relevant the design is to the case studyneighborhood versus its broad applicability in other communities. While theenvironmental justice concerns and accessibility aspects covered by the seventeenindicators can be applied to other marginalized inner-city neighborhoods in theUnited States, the indicator definitions themselves evolved from a negotiation withneighborhood residents, and therefore reflect the specific needs and desires of theSHN. Defining access to services based on the provision of certain retail stores



and community amenitiessuch as recreation centersmight be conceptualizedin an entirely different manner in another neighborhood. The contextual elici-tation of indicator thresholds with stakeholder groups is pivotal to the SSP process,but does not lend itself to use in comparative assessments.

In addition, the consistency analysisthough guided by empirical literature to acertain extentwas still highly subjective in its determination. For example, theindicator Household Transportation Budget is consistent up to level 3 with the firstthreshold of the indicator Transportation Mode Share. Beyond that point, it isassumed that reducing household transportation budgets to between 8%12% ofdiscretionary spending will require that fewer than 70% of trips be taken by privatecar (See Tables 2 and 3 for comparison between indicator thresholds). However,this inconsistency is an assumption, and not empirically testedat least not withinthe SHN. The SSP is simply a tool for systematically managing where consistencyoccurs between different parameters (i.e., indicators) in a defined system. Themethod cannot quantitatively measure the correlation in performance betweentwo indicators; for this, empirical research must be separately undertaken. How-ever, since the effect of each of the 17 indicators must be examined on all othersto provide a full assessment, the development of an empirical study to verify thethreshold levels at which consistency occurs would be a formidable task.

Additionally, the SSP is a visioning tool, but does not provide guidance on theappropriate strategies required to implement that vision. Nevertheless, duringboth the stakeholder workshop and the meeting with the chief city planner, indi-cator thresholds were agreed upon that outlined both the degree of action to betaken, and assigned responsibility to a specific stakeholder. For example, when dis-cussing threshold levels for the indicator Perceptions of Safety, residents agreed(in principle) to form a neighborhood watch group using members of the resi-dents association in order to patrol streets that were considered to be particularlyvulnerable (see Table 2). In recognizing this, the residents used a visioning exer-cise to define a specific action (which they had control over) that they couldimplement to realize their vision of a safe neighborhood. Similarly, the meetingwith the city planner resulted in an agreement for a threshold level of the indicatorIABC (see Table 3) which tasked the City with developing and managing a policy tocap and trade parking spots between commercial property owners. These exer-cises also demonstrated that, in many cases, it was impossible for the participants toconceive of a vision without simultaneously considering an action to support it,evocative of Innes (1990) theory of joint knowledge and action production. Manyof the indicator threshold levels reveal both a vision and an action, and the pur-pose of the consistency analysis was not only to eliminate conflicting visions, butalso to eliminate conflicting actions. The SSP may be suitable for balancing conflict-ing strategies as much as it is useful for balancing conflicting visions -and perhaps afurther study of the SSPs application to strategy development is warranted.

The SSP must still be considered a work in progress, and future research willfocus on tackling issues of empirical substantiation and finding ways to makethe method more broadly applicable. In addition, we should strive to create anenhanced SSP that provides an even more robust characterization of the differentsocio-economic facets behind mobility patterns and endeavor to incorporate evengreater levels of citizen involvement in the research process.



ACKNOWLEDGMENTS

We would like to acknowledge the support of Arnim Wiek, Carol Johnson, JoeLarios, Lauren Withycombe, and the Sky Harbor Neighborhood Association formaking this research possible.

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