Conceptual Design


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Conceptual Design

  1. 1. Source: LAND DEVELOPMENT HANDBOOK PART III CONCEPTUAL DESIGN Dennis Couture, A.S.L.A., R.L.A. Introduction developed as part of this initial conceptual design phase. Conceptual Design represents the initial effort of describing The ensuing discussion with the development team may alternative plans that satisfy the development program ob- prompt a dialogue as to the pros and cons of the various jectives in light of the site characteristics identified in the solutions and identify problems the designer alone may not site analysis. It requires full recognition of the client pro- have anticipated. The end products associated with the con- gram components, initial site assessment, site context, and cept design phase may be a series of sketches or diagrams planning and regulatory controls. highlighting the distribution of land uses and preliminary Sketches, functional diagrams, or concept plans are nor- infrastructure requirements. The diagrams themselves may mally completed to illustrate a framework for the given de- be annotated to underscore the advantages or disadvantages velopment program. They generally represent diagrams of associated with the depicted solution and memorialized for the potential distribution of land uses and major circulation future reference. requirements. The effort seeks to meld all pertinent com- As demonstrated in Figure III.1, conceptual level prehensive or master planning information with site-specific sketches generally include preliminary delineation of such considerations to illustrate how the site might best be de- considerations as: veloped. For large-scale development, this initial cut at the design effort is often accomplished in what are termed Points of site access together with an initial align- ‘‘blob’’ or ‘‘bubble’’ diagrams. The intent is focused less on ment of major vehicular circulation routes. The sophisticated graphic technique and more on fostering di- principal road network should be developed in the alogue, a preliminary review and assessment, and confir- context of any public comprehensive or master plan- mation of design direction among the design team participants. Concept plans reflecting land use distribution ning policies or recommendations. and associated circulation are reviewed in the context of A distribution of major land use elements by type. their preliminary implications on infrastructure require- The delineation should reflect the approximate area re- ments as well as economic, functional and political feasi- quirement for each use to begin to gauge the massing bility. This phase, similar to the more subjective assessment or relative area requirements necessary to accommo- included in the initial feasibility and site analysis steps, date individual program components. moves from the review of general intent to actual physical diagramming of use arrangements. This level of conceptu- Delineation of areas mandated or desirable as open alization is generally completed prior to the investment of space based the previously completed site analysis, resources and time resolving more detailed levels of design. such as floodplain, protection areas, wetlands, mature STEP 3: CONCEPTUAL DESIGN woodland, and streams and stream valleys. There are generally multiple solutions for the design of any Preliminary determination of the need and location one site. It is common for alternative concept plans to be of major public facilities such as schools, parks, fire Downloaded from Digital Engineering Library @ McGraw-Hill ( Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website.
  2. 2. CONCEPTUAL DESIGN Conceptual design. III.1 F IGURE 190 Downloaded from Digital Engineering Library @ McGraw-Hill ( Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website.
  3. 3. CONCEPTUAL DESIGN CONCEPTUAL DESIGN 191 stations, and libraries, as identified in public planning able for early discussions with appropriate public officials. documents They provide sufficient information to obtain an informal assessment by appropriate public agents/officials as to the While normally not a formal public submission docu- development plan’s compliance with public comprehensive ment, conceptual sketch plans do provide information suit- and land use policies and the local political climate. Downloaded from Digital Engineering Library @ McGraw-Hill ( Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website.
  4. 4. CONCEPTUAL DESIGN Downloaded from Digital Engineering Library @ McGraw-Hill ( Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website.
  5. 5. Source: LAND DEVELOPMENT HANDBOOK CHAPTER 12 DEVELOPMENT PATTERNS AND PRINCIPLES Dennis Couture, A.S.L.A, R.L.A INTRODUCTION growth and green infrastructure offer meaningful insight This chapter presents an overview of some of the more into responsible land development activity. These latter con- prevalent land use types and development patterns that siderations are appropriate across the spectrum of urban- comprise our contemporary built environment. It offers a rural development activities. general discussion regarding development intensities and An extensive overview of the basic tenets associated with design patterns, including some of the more widespread these more recent ideological approaches to land develop- influences on development activity. Such influences range ment is beyond the purview of this chapter. Contemporary from aesthetic and prevalent community attitudes regarding literature and professional journals abound with informa- tion on both theory and practical application. Familiarity land development project design to the more formative fac- with this information is particularly relevant for land design tors associated with environmental, political, and economic agents given that these approaches are perhaps more inter- considerations that guide site design and engineering ac- twined in the livability and marketing side of land devel- tivity. opment and site design than might be evident from in-place Perhaps the most overriding consideration for any land land use regulatory controls, statutes, and zoning codes. development endeavor should be the project at hand in the This chapter provides an overview of prevalent contem- context of the larger community. Community in this sense porary land use types. Residential and select nonresidential is more than the physical characteristics of a given project’s building considerations are presented in isolation of each surrounds. It embraces the extant sociocultural, political, other. Although this format may be considered anathema and economic paradigms that model the dynamics in any to proponents urging greater integration of potentially com- given jurisdiction, resulting in the land development types patible or supportive land uses, extensive discussion of such and patterns that are built. As local context offers a guide endeavors, even in the context of current mixed use and to project design opportunities, so do more universal con- planned developments, is not the objective here. Rather, structs that have evolved in response to the real and per- identifying some of the base considerations associated with ceived shortfalls of contemporary development trends. select land use types may provide a cursory foundation for Sensitivity to the urban-suburban-rural distinction in de- better appreciating and identifying what may be unique to velopment types is simplistic. Development considerations each use and how they may be best integrated. that are mindful of the community-making and place- A variety of factors determine the type and configuration making opportunities and design principles associated with of a given land use, including the expectations of landown- traditional design, such as traditional neighborhood design ers, users, and consumers; the availability of land; the cost (TND), neotraditional, and new urbanism, afford a renewed of construction; the natural attributes of the site; and the perspective on both the dynamics of community and the character of the surrounding community. These are modi- opportunities for meaningful site and project design. Sim- fied to a great degree by local regulations, which are based ilarly, constructs associated with the advocacy of smart largely on more encompassing issues of health, safety and 193 Downloaded from Digital Engineering Library @ McGraw-Hill ( Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website.
  6. 6. DEVELOPMENT PATTERNS AND PRINCIPLES 194 C O N C E P T U A L D E S I G N welfare, local considerations relative to the nature of local growth, housing, transportation, community facilities, and commerce, prevalent community attitudes, and past com- land use. While a comprehensive plan may contain a munity practice. mapped graphic representation of what the community An examination of the zoning ordinance in all but the might look like at some point in the future, the local zoning smallest communities reveals great variety in the categories ordinance and zoning map are the tools that provide the of permitted land uses. Typically, this includes residential, day-to-day implementation effecting land use decisions rel- commercial (sometimes broken down into retail and office ative to the overall comprehensive plan policy objectives. A uses), and industrial uses. Depending on the size, location, clear understanding of the distinction between these doc- and maturity of the community, a jurisdiction’s zoning doc- uments is imperative to understanding the extant land use ument may establish other land use categories to reflect its patterns associated with development activity in any given unique economic base, such as manufacturing, agriculture, community. Decision-makers in land development and de- maritime, mining, forestry, and institutional uses, to cite a sign must be sensitive to the rationale for the type and use few. Furthermore, the zoning ordinance, as discussed else- intensities identified in the comprehensive plan. They must where in this book, normally identifies a series of de- also be fully apprised of the design standards and criteria velopment standards, commonly expressed as minimum governing the size, form, and character of proposed devel- requirements focusing on such elements as lot size, building opment, as identified in the local zoning ordinance and height, yard requirements, open space, and impervious similar regulations. cover. It may be useful for the novice to consider a local com- That architectural styles vary in different geographic munity as a single large planned community. The compre- regions in the country is no surprise. Regional variation in hensive plan and its associated policy statements represent history, culture, and heritage affects development patterns the collective public vision to guide community growth. in density and configuration as well. Different names are Various ordinances and regulations provide the means to often used to describe similar types of land use. implement that vision. Together they provide the two im- Most local regulations are extremely specific concerning portant elements that establish the foundation for land de- permitted density, height, bulk, and setback requirements velopment patterns in a community. for most land uses. To attempt to assemble and reproduce Historically, zoning ordinances have relied on the delin- this wide range of specifications would be neither produc- eation of distinct geographic zones or districts that accom- tive nor useful. The discussion of land uses, development modated the development of one land use type. These intensities, and the design principles in this chapter is in- districts generally included residential, commercial (nor- tended as a primer. mally inclusive of office and retail uses), and industrial cat- If there is a common denominator throughout contem- egories. Subcategories of each use may stipulate gradations porary development, it may be its heavy reliance on the in density within a land use, prompting alternative devel- automobile as the principal means of transportation. The opment patterns or building programs. While much land suburban development pattern is characterized by a strong activity is rooted in a single zone/single use development dependence on the car for both work- and leisure-based pattern, more flexible development patterns and land use trips. Historically, the separate clustering of residential and combinations are fostered by development controls that employment areas at density levels low enough to make perpetuate planned, planned unit, and mixed use devel- public transportation infeasible have reinforced this. The opments. The objective of these latter categories move be- single-occupant automobile continues to be the most prev- yond singular use and attempt to foster a framework for alent form of transportation in the suburbs. This phenom- greater variety in permitted land uses and arrangements. enon places a unique set of requirements on resulting land Prior to discussion of individual development types, it will use types and development patterns. Attention to a com- be valuable to outline briefly some of the more encom- mon need for both vehicular circulation and on-site parking passing planning terms. is necessary. Streets and roads provide the common linkage between and within land uses and the principal framework Conventional Subdivision of the resulting development patterns. Similarly, parking re- The historic basis for much suburban land use is the con- quirements for the automobile are a major design element ventional subdivision, created by the division of larger land in the sizing and organization of individual land uses. tracts into smaller land units. Such subdivision generally requires new streets for accessing the newly created smaller DEVELOPMENT TYPES land units or lots. The subdivided acreage provides individ- Ideally, a community seeks to guide its growth in a manner ual lots for houses and lots or parcels for nonresidential consistent with its heritage, common goals, and economic uses. While subdivisions have become varied in pattern, lot interests. Local land use activity is guided by comprehen- size, street alignment, open space network, and in some sive or master planning, representing a compendium of pol- cases a mix in permitted land uses, conventional develop- icies, usually subjected to arduous public participation, ment continues to be predicated on the simple subdivision focusing on topics such as population and economic of land. It has been the mainstay of suburban residential Downloaded from Digital Engineering Library @ McGraw-Hill ( Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website.
  7. 7. DEVELOPMENT PATTERNS AND PRINCIPLES 12 DEVELOPMENT PATTERNS AND PRINCIPLES 195 development and accommodation of proximate retail, em- Cluster subdivision requires increased attention to the ployment, and public facilities. details of design. Reliance on smaller lots necessitates regard The larger tract acreage is divided in a manner that pro- for other methods of maintaining privacy and buffering be- vides for complete transfer of land ownership to subsequent tween residences. Often greater controls are placed on unit users. Streets are normally incorporated into public own- design and orientation. Design controls often exceed stan- ership, and community open space, if provided, may be dards enumerated in zoning and subdivision regulations. It deeded to an appropriate public or semipublic entity. Single is common for cluster development to be executed as or multiple builders may on a lot-by-lot basis, initiate con- planned developments, as discussed below. A typical cluster struction. Figure 12.1 below represents a typical conven- subdivision is presented in Figure 12.2. tional subdivision. Planned Unit Development (PUD) Cluster Subdivision A planned unit development (PUD), as its name implies, Cluster development relies on subdividing larger properties is planned as a single entity and usually represents some into smaller lots or parcels, but differs from conventional minimal-sized contiguous acreage, as specified by local subdivision in that it typically results in a land plan with a ordinance. It contains single or multiple residential clusters greater percentage of the overall acreage set aside in com- or planned units with provision for public, quasipublic, mon, community, or conservation open space. To achieve commercial, or industrial areas. Normally, nonresidential this open space, local regulations generally allow a reason- uses are provided in a ratio to residential uses, as stipulated able reduction in individual lot size and associated setbacks, by ordinance. Planned unit developments generally provide provided there is no increase in the overall number of lots for a mix of housing types and land uses and situate de- that would otherwise be permitted under comparable con- velopment within an overall open space system, with an ventional subdivision. The resultant land area not placed in emphasis on amenity provisions and preservation of natural individual building lots is normally devoted to common resources. Figure 12.3 is representative of a planned unit open space. This development pattern allows for the con- development. centration of building activity on the more usable areas of a site and ideally results in a reduction in development costs Planned Community or Master Planned Community associated with site grading and supporting infrastructure. The planned community usually provides for a wider range Cluster subdivisions are also often used to protect environ- of residential land uses and includes commercial-retail, em- mentally sensitive areas of a given site. The reduction in ployment, recreation, and institutional uses to create a individual lot size and associated exterior yards is compen- balanced hierarchical community. Planned communities sated for by the communal open space that is made avail- represent large land assemblies that attempt to satisfy a full able. F IGURE 12.1 Conventional subdivision. F IGURE 12.2 Cluster subdivision. Downloaded from Digital Engineering Library @ McGraw-Hill ( Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website.
  8. 8. DEVELOPMENT PATTERNS AND PRINCIPLES 196 C O N C E P T U A L D E S I G N F IGURE 12.3 Planned unit development. Downloaded from Digital Engineering Library @ McGraw-Hill ( Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website.
  9. 9. DEVELOPMENT PATTERNS AND PRINCIPLES 12 DEVELOPMENT PATTERNS AND PRINCIPLES 197 range of lifestyle and support elements to sustain its resi- ciated with these mitigation measures. The concentra- dent population. Normally, development is undertaken by tion of density within a site may require less extensive a single owner or master developer who in addition to or- required mitigation activity, or at least contain it. chestrating the financing, planning, and design of a project may construct the required infrastructure and community Aesthetic Impacts and Opportunities amenities, making sites available to others for individual building construction. Figure 12.4 represents a master Context: Compatibility with adjoining land uses can planned community. become problematic as proposed development intensity increases. Careful site planning and design can assist in DEVELOPMENT CONSIDERATIONS mitigating this problem. Structural solutions may be A development team must consider the effect that each type costly, and buffering solutions may be land consump- of land use has on environmental, aesthetic, financial, op- tive. erational, and marketing characteristics of a land develop- Architectural design: More intense development gen- ment project. They should understand the relationship erally requires more stringent architectural controls to between these characteristics and their effect in offsetting ensure overall visual coherence. Modest building ele- the impacts of development. These may range from physical ments on large lots or parcels benefit from distance be- limitations inherent in the site to a community’s predispo- tween improvements. Individual units capture their sition to a proposed program of land development. Follow- own identity and are less visually and functionally de- ing are some characteristics that warrant consideration in pendent on their neighbor. As building size increases their implications on resulting land use patterns. or parcel size decreases, increased proximity warrants Generally, there is a direct relationship between the in- greater attention to issues of compatibility. tensity and density of development and its impact on the site and surrounding community. These concerns may focus External views: Larger buildings or more intense on the following: building programs may impact the extent and quality of exterior views. Denser development requires careful site planning to ensure privacy and minimize the Environmental Impacts and Opportunities visual and noise impact of abutting uses. Site disturbance: More clearing and grading is re- Financial Impacts and Opportunities quired as buildings, site improvements, and infrastruc- ture occupy an increasing proportion of land. There is Infrastructure: While higher-density development normally a reduction in the opportunity to retain natu- generally requires higher total infrastructure costs, it ral grade as density increases. Opportunities to pre- may result in lower construction, operation, and ser- serve existing wooded or natural areas are similarly vice costs on a per unit or square foot basis. reduced as building program coverage is expanded. Lower building density does not in itself result in less Land: Higher-density development permits land impact. It is the combination of existing conditions, costs to be distributed within a larger development proposed program, and resolution of program detail program, resulting in lower per unit land costs. that eventually delineates the degree of impact. An Site amenities: Although higher density may require equivalent program in a more compact development a more elaborate amenity program, the increased pro- envelope can have substantially less site disturbance ject development yield and resulting revenue may pro- impact than a comparably sized program dispersed vide an incentive for such provisions. over a greater amount of acreage. Similarly, building programs that are tailored to unique site conditions Construction: Typically, more intense development can have less impact on land than generic solutions. results in higher total construction costs. It may foster For example, a residence designed for a steep site will certain economies in construction due to the potential have a better fit and require less grading than one for distributing costs over a larger program base. Con- originally designed for level terrain. centrated building programs generally provide a lower per unit construction cost than a similar program dis- Stormwater management: As the impervious surface persed over a larger area. Such reduction results from associated with a given development program in- savings associated with a more compact building enve- creases, so does stormwater runoff, along with the in- lope and shorter lengths of expensive infrastructure. creased potential for non-point source pollutants. Conversely, greater opportunities exist for storm drain- Public/semi-public facilities: Aggregate and per unit age control, erosion and sediment control, and best operation and maintenance costs of select facilities may management practices, in that higher density can assist be reduced with denser development patterns. This is in financially compensating for construction costs asso- particularly important for major capital facilities, such Downloaded from Digital Engineering Library @ McGraw-Hill ( Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website.
  10. 10. DEVELOPMENT PATTERNS AND PRINCIPLES 198 C O N C E P T U A L D E S I G N F IGURE 12.4 Planned community. Downloaded from Digital Engineering Library @ McGraw-Hill ( Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website.
  11. 11. DEVELOPMENT PATTERNS AND PRINCIPLES 12 DEVELOPMENT PATTERNS AND PRINCIPLES 199 as a sewerage treatment plant. These may be funded by municipal bonds or special assessment or develop- ment association fees and rely heavily on project usage to retire debt. The building of major private facilities, such as utility transmission lines, also relies on de- mand to justify new construction. Tax revenue: Tax revenues generally increase on an acreage basis as a result of public and structural im- provement, and subsequently increased density nor- mally results in a higher average per acre assessed value. Municipal service: Public service improvements can F IGURE 12.5 Typical conventional lot. more readily be supported by concentrated population and development patterns, which afford a more effi- cient delivery system. nance. Similarly, in a cluster lot, the single-family structure Operational Impacts and Opportunities is surrounded on all sides by yards reserved for the occu- pant’s exclusive use; however, the lot may be smaller than Maintenance: Occupants realize lower per unit normally prescribed under conventional zoning and the maintenance costs due to economies of scale associated yard setbacks are generally lessened. Figure 12.5 is repre- with larger, more intense development patterns. sentative of a typical conventional subdivision lot, and Fig- ure 12.6 represents its cluster equivalent. Energy: Per unit energy cost savings are generally Utilization of cluster lots requires greater attention to realized in development that is more compact. house siting and house-to-house relationships, given the need to preserve individual unit privacy and maintain com- Marketing Impacts and Opportunities munity design standards among smaller average lot sizes. The benefit of cluster development rests with the potential Market exposure: Increased scale, intensity, or qual- reduction in per unit infrastructure costs, given the aggre- ity of development may foster a visual presence, which gation of dwellings on only a portion of the project acreage. translates into greater market exposure. Depending on Similarly, the conservation of community open space in the actual development program, this may increase cluster arrangements and its amenity appeal may offset mar- project appeal to a broader spectrum of the market or ket concerns about smaller lot sizes and the potential re- increase awareness among targeted consumer groups. duction in individual unit privacy. Conventional or cluster Community identity: Larger-scale developments can arrangements alone do not dictate lot size. Relatively speak- provide additional justification for amenities, which ing, large and small house types may be developed in either may, in turn, increase community identity and arrangement. While acre and multiple-acre home sites are resident/tenant affinity with a project. common in suburban areas, more typical single-family de- tached lots ranged from 1⁄4 to 1⁄3 acre in size throughout RESIDENTIAL LAND USE most of the last several decades. However, current trends Typically, housing is the most prevalent land use within a are moving toward smaller lot sizes, given escalating land jurisdiction. Residential design requires sensitivity to the costs and changing lifestyle requirements. Single-family de- pragmatics of sound construction economics, an under- standing of site conditions, and an appreciation for con- sumer lifestyle preferences. Similarly, sound residential planning and design requires a genuine appreciation for the individual dwelling unit. Single-Family Detached In a single-family detached residential dwelling, each indi- vidual living unit is a freestanding structure. Each dwelling unit normally occupies a separate recorded lot. In a con- ventional lot arrangement, the single-family home is sur- rounded on all sides by property or yards reserved for the occupant’s exclusive use. The lot must meet a minimum or average size prescribed in the community’s zoning ordi- F IGURE 12.6 Typical cluster lot. Downloaded from Digital Engineering Library @ McGraw-Hill ( Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website.
  12. 12. DEVELOPMENT PATTERNS AND PRINCIPLES 200 C O N C E P T U A L D E S I G N tached dwellings on 2000–5000-ft2 lots are increasingly erations are based on sound site planning and community common in both in-fill developments and planned com- design criteria. munities. Zoning ordinances generally provide setback and yard Lots are normally square or slightly rectangular in shape. requirements for single-family residential development to Minimum lot widths are generally governed by local zoning ensure functional side, rear, and front yards. Front yard set- ordinance. Decisions to exceed that dimension are often backs are generally a minimum of 20 to 30 ft to accom- prompted by market demand for additional distance be- modate the length of a parked vehicle in the driveway. Front tween dwelling units, the dimensions of the proposed yard setbacks may vary depending on the nature and scale house, or preferred driveway approach to the garage. An of the adjacent street. Lesser setbacks may be acceptable attached side-loaded garage requires a wider lot than a sim- where alternative parking arrangements are provided, as is ilarly sized front-loaded facility. the case where rear-accessed alleys or service drives are em- Lot lines normally run perpendicular to the street front- ployed. Deeper setbacks may be required along more heav- age. Variations in lot configuration commonly include pie- ily traveled arterial streets than on neighborhood streets or shaped lots around cul-de-sacs and flag or pipestem lots. cul-de-sacs with less traffic volume. The latter convention provides limited lot width along the Demand for affordable single-family detached housing in public street frontage to accommodate driveway access and a time of escalating land prices has prompted greater reli- a widening of the lot at the building setback line sufficient ance on smaller lots. The smaller lot size not only appeals to satisfy the desired house type and its yard requirements. to builders and developers who can realize lower per unit Examples of these lot configurations are presented in Figure infrastructure costs and higher per acre unit yields but re- 12.7. sponds to consumer preference for the reduced mainte- Pipestem or flag lots were originally designed to allow nance requirements associated with the smaller yards. access to otherwise landlocked parcel acreage. Use of this Smaller lots in well-designed communities with provisions technique recognizes the environmental and economic ad- for common amenities appeal to a lifestyle that seeks con- vantage in substituting private drive lengths to tap land that venient accessibility to diverse leisure activities. Safeguards otherwise would require additional street length and poten- to a well-designed small lot community reside in well- tially greater site disturbance and infrastructure costs. The conceived architectural design of the unit and sensitive site negative attributes of this technique include the potential planning. burden on homeowners to individually maintain longer Design Considerations. While conventional subdivision driveways or private street lengths, potential access con- regulations normally prescribe setbacks for front, rear, and straints for emergency vehicles, and possible undesirable side yards, dwelling unit design, variation in lot sizes, lot house-to-house relationships, as pipestem dwellings may be dimensions, and concessions suited to cluster or unique perceived to be in the rear yards of adjacent residences. detached housing prototypes provide opportunities to tailor However, judicious use of pipestem lot arrangements can design to local market and site conditions. Several ground provide distinct benefits in residential design when its use, rules can provide a strong foundation to residential layout resulting lot size, dwelling orientation, and access consid- design. These include: F IGURE 12.7 Example of variation in lot size due to site char- F IGURE 12.8 Example of the use of flag lots in lieu of extended acteristics. street length. Downloaded from Digital Engineering Library @ McGraw-Hill ( Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website.
  13. 13. DEVELOPMENT PATTERNS AND PRINCIPLES 12 DEVELOPMENT PATTERNS AND PRINCIPLES 201 common floors and ceilings. Each unit has a separate pri- vate entrance at grade level and usually a contiguous ex- terior yard reserved for the occupant’s exclusive use. Variations may include: Townhouse (Row House or Townhome). Made up of three or more units attached side-by-side, the townhouse, long a common urban housing prototype, has become a popular component of the suburban housing market. A common or party wall separates individual units, each with an at-grade entry. Property on at least two sides, normally front and back, is generally reserved for the occupants’ exclusive use. The townhouse provides flexibility in plan and style, with design variations that include integral or detached ga- rages. Indoor/outdoor relationships generally focus on the rear yards, although they may orient to small front court- yards. Exterior yard privacy may be enhanced with land- scaping, fencing, or privacy walls. Lot widths can vary depending on the desired character of the unit. While con- ventional suburban townhomes may range from 16 to 24 F IGURE 12.9 Example of variation in lot size due to site char- ft wide, units of 32 ft or greater are not uncommon when acteristics. market considerations warrant a street presence approach- ing that of a single-family detached residence. At the more conservative widths, lot depths may range from 60 to 100 Lot and place houses in a manner that responds to ft. Densities normally range from 7 to 12 units per acre. the site’s natural features. Depending on the unit width, parking requirements, site conditions and desired community character, densities of Avoid extremes in either random plan organization up to 20 units per acre are not uncommon in more urban or uniformity to the point of monotony in the pattern settings. The figures below illustrate a range in townhouse of development. configuration, including the more conventional front- Establish appropriate block lengths to minimize loaded unit, courtyard or clustered townhouse court, and long views of repetitive house-fronts, garages, and alley-served units. driveways as well as foster convenient vehicular and Each townhouse dwelling has a separate front door, al- pedestrian movement. though end units may be side entry. Generally, each house has its own utility connections. Typically, local ordinances Ensure yard dimensions and unit orientation that prescribe the maximum number of side-by-side units that promote individual dwelling legibility and sufficient may be aggregated into a single townhouse ‘‘stick’’ or build- yard privacy. ing group. While sticks of six to eight townhouses have The street pattern should result in a coherent and been a common development practice, combinations of legible circulation system to support an identifiable three to four units, comparable in scale to a large single- sense of place. family residence, are popular in some high-end market seg- ments. Building setbacks should reinforce the street hierar- Building lengths with more than eight attached units are chy. more commonly found with narrow, 18-ft or less average unit widths. Shorter lengths, and a higher percentage of end Single-Family Semidetached units are generally associated with wider upscale town- The single-family semidetached dwelling, commonly re- homes or in instances where parcel dimensions preclude ferred to as a duplex unit, consists of two living units that longer lengths. occupy a single structure separated by a common wall. Each While the urban townhouse was configured in a linear dwelling has its own exterior entrance and is located on a arrangement with units oriented to the street, the suburban separate recorded lot. Each dwelling unit is surrounded on townhouse community has taken on a more organic ar- three sides by property reserved for the occupant’s exclusive rangement. This has occurred in response to site conditions, use. which have accommodated a more expansive layout, as well as a proclivity toward arrangements in which the units’ Single-Family Attached fronts face towards the parking lots and whose rears are Single-family attached dwellings include housing types with open-space amenities. The urban street setting, with its at- multiple dwellings in a building arrangement where two or tendant parallel parking and supplemental rear service alley more dwellings share common walls, and in some cases access, had been preempted, in the suburbs, by the front Downloaded from Digital Engineering Library @ McGraw-Hill ( Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website.
  14. 14. DEVELOPMENT PATTERNS AND PRINCIPLES 202 C O N C E P T U A L D E S I G N ning to ensure the convenient placement of adequate park- ing for each unit. Reliance on a single exterior exposure for each residence requires subtle design considerations to bal- ance the semipublic nature of a front entry with any privacy requirements associated with the singular exterior living space, which occupies the same facade. Other Townhouse Variations. Another variation to the townhouse is the stacked or piggyback townhouse. This may include a multistory townhouse unit over a single-story flat or a multistory townhouse over a similar multistory unit. Such arrangements work well on sites where topo- graphic change will allow upper and lower units to be ac- cessed at grade on opposing sides of a building. In extreme instances, the lower unit may be reduced to a single exterior exposure. Alternating townhouses with stacked flats in the same building can produce additional diversity. The flats, some- times referred to as coach homes may be located either at building ends or in interior locations. This arrangement is often classified as a multifamily residential product subject to zoning requirements associated with that use category. Figures 12.13 and Figure 12.14, respectively, illustrate the combined townhouse/coach house and piggyback/stacked townhouse. Multi-Plex. Used with a prefix representing the number of attached units, such as duplex, triplex, quadraplex, etc., multiplex residences consist of two or more units in various configurations, each with its own separate at-grade exterior entrance. Piggyback townhouses and manor houses are of- ten considered multiplex units. The yards surrounding a typical multiplex unit may be reserved for common occu- pant use or portions of the yards may be designated for an individual unit’s exclusive use. Figure 12.15 shows a variety of multiplex combinations. As the number of units in this type of attached residen- tial arrangement increases, unique opportunities and con- F IGURE 12.10 Typical townhouse condition. straints in both design and construction arise. Unit design, solar orientation, indoor/outdoor relationships, privacy provisions, convenience of automobile access, and parking service drive and its associated perpendicular parking. Var- must be weighed against the increase in density and reduc- iations do include townhouse layouts, which focus on a tion in per unit land, construction, and infrastructure costs. court and mews arrangement of units. The former generally results in a cluster of townhomes fronting on a common Multifamily Residential parking area, often referred to as parking court or parking Multifamily structures are characterized by four or more bay. The common vehicular circulation area serves as the units in a single building, with units sharing access to the organizer for the cluster. The mews arrangement focuses on exterior by one or more common entrances. Structures may a pedestrian open space to organize the front facades of the be one or more stories, and multifamily communities or individual townhomes, with parking occurring at the ter- developments may consist of one or more buildings on a minus of the pedestrian area or on the rear or underside of single tract or lot. Structures are surrounded by common the units. open space, which often contains on-site recreational facil- Back-to-Back Townhouse. While considered an attached ities for resident use. Private drives or service roads provide multifamily housing type in many jurisdictions, the back- access to surface parking lots or in some cases structured to-back townhouse often divides the length of a traditional parking, private garages, or carports. townhouse stick with an additional common wall that Most zoning ordinances specify detailed design criteria serves to separate units organized along opposing facades. and development standards for multifamily projects. Project The resulting aggregate building form has two front yards. density is usually set as a maximum number of dwelling The double frontage prompts a need for careful site plan- units per acre or, in some instances, may be expressed as a Downloaded from Digital Engineering Library @ McGraw-Hill ( Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website.
  15. 15. DEVELOPMENT PATTERNS AND PRINCIPLES 12 DEVELOPMENT PATTERNS AND PRINCIPLES 203 F IGURE 12.11 Traditional townhouse unit arrangement. maximum permitted square feet of building or floor area to be maintained in the event that one entrance becomes coverage per acre of land. obstructed. Minimum standards are adopted to guard against over- Site planning for multifamily developments requires an crowding, ensure access to light and air, protect privacy, and appreciation and understanding of the proposed building ensure compatibility between land uses. Most jurisdictions design. The higher densities, size of structures, and rela- seek to locate multifamily residential development in areas tionship between structures and site elements leaves less where land costs are high. Typically, this type of develop- latitude than may be afforded in site design for less dense ment coincides with areas of considerable existing or residential housing types. The placement of driveways, lo- planned investment in public infrastructure, or where prox- cation and sizing of parking areas, and other infrastructure imate commercial retail and office activity would benefit considerations require knowledge of building dimensions, from higher-density residential development. In this regard, elevations, and orientation. multifamily housing often provides the buffer between non- Multifamily structures are generally categorized as either residential activity and single-family attached and detached garden or low-rise, mid-rise, or high-rise structures. Dis- developments. tinctions and characteristics of each of these are described Due to the more intense traffic generation resulting from below. the higher densities associated with multifamily housing, Garden apartments, sometimes referred to as walk-up or convenient access to major collector or arterial streets is low-rise, consists of one- to four-story structures. The in- desirable. Depending on the size of a development, local dividual apartment units may be arranged along corridors fire and public works officials may require at least two en- or around common stairwells, which may be enclosed trances or connections to a public street. This allows access within the structure or unenclosed and integrated into the Downloaded from Digital Engineering Library @ McGraw-Hill ( Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website.
  16. 16. DEVELOPMENT PATTERNS AND PRINCIPLES 204 C O N C E P T U A L D E S I G N F IGURE 12.12 Back-to-back townhouse. Downloaded from Digital Engineering Library @ McGraw-Hill ( Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website.
  17. 17. DEVELOPMENT PATTERNS AND PRINCIPLES 12 DEVELOPMENT PATTERNS AND PRINCIPLES 205 F IGURE 12.13 Combination townhouse and coach house arrangement. exterior architectural design. While some units may have which the individual unit runs from the front to the rear of direct private entrances at grade level, normally units share a building (through-units) to double-loaded arrangements common entries. As the name implies, the garden apart- where in each unit has a single (front or rear) exposure. In ment focuses on melding the dwelling unit to the building terms of site design, awareness of interior room organiza- grounds. The building units are generally organized around tion and relationship to exterior space is important to pro- landscaped open space and parking areas. Ground floor mote desirable views and to enhance individual unit units may have direct access to exterior patios or garden privacy. This is particularly important where parking is con- areas, and upper floors may have balconies or terraces, pro- centrated near the building. Provision of intermediate land- viding each individual unit with exterior living space. scape between the unit and the parking area enhances the Garden apartment building configurations vary depend- livability of the dwelling, particularly if it is the unit’s sole ing on a myriad of marketing, program, and site consider- exterior exposure. Figure 12.16 illustrates single- and ations. They can range from single-loaded buildings in double-loaded garden apartment layouts. F IGURE 12.14 Piggyback or stacked townhouse. Downloaded from Digital Engineering Library @ McGraw-Hill ( Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website.
  18. 18. DEVELOPMENT PATTERNS AND PRINCIPLES 206 C O N C E P T U A L D E S I G N F IGURE 12.15 Typical Multiplex Combinations: triplex, quadraplex, eightplex. Garden apartments afford significant flexibility in site de- Mid-rise and high-rise multifamily residences are generally sign due to the adaptability of various building forms to four- to eight-story structures. High-rise residences nor- divergent site conditions. Unit densities can range from 10 mally exceed eight stories. Both rely on elevators for vertical to 20 units per acre, depending on the building config- circulation. Individual dwelling units access common cor- uration, unit sizes, number of stories, parking, open space, ridors. Units are generally arranged along opposite sides of and amenity packages. In an effort to appeal to varying the corridor, providing a single exterior exposure for the markets, garden apartment communities increasingly pro- principal interior living spaces. While the economies of mote amenity packages that expand beyond the traditional construction weigh heavily in favor of this arrangement, swimming pool to include facilities complete with spas; ex- unique market considerations may prompt alternative de- ercise, game, meeting and community rooms; and ex- sign, such as single-loaded corridors, as in the case where panded site improvements including tot lots, court facilities, a unique amenity mandates that all units have comparable trails, and park courses. Multifamily residents increasingly exposure to the attraction. desire amenities comparable to those provided in single Internally, buildings are organized around the elevator, family residential communities. Even sheltered parking utility, and a stairwell core, which may be central to the such as carports, or more infrequently individual garages, building floor plate. Entered at a common lobby, or mul- is an increasingly popular element in select garden apart- tiple lobbies at differing levels, if terrain permits, the cor- ment communities. ridors penetrate the building extremities providing access to the individual residential units. Additional stairwells po- sitioned at the further reaches of the corridor provide an alternative means of access/egress. The concentrated need for service and delivery is generally satisfied by a central loading area, which is often located to the rear or side of the building removed from main tenant access and view. Figure 12.17 is illustrative of a typical mid- and high-rise multifamily floor plate. Four- to eight-story multifamily buildings can achieve densities of 30 to 40 units per acre. Provision for parking increasingly relies on subsurface or structured arrangements to maximize land use efficiencies and promote tenant con- venience and safety. Many of the amenity provisions of mid- and high-rise residential buildings may be internal to the structure, but exterior elements may include a full range of recreational and leisure activity areas. In more urban settings, this may F IGURE 12.16 Example of double-loaded and single-loaded include indoor or rooftop swimming pools, landscaped ar- garden apartments. rival courts, and lush landscaped perimeters. On more ex- Downloaded from Digital Engineering Library @ McGraw-Hill ( Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website.
  19. 19. DEVELOPMENT PATTERNS AND PRINCIPLES 12 DEVELOPMENT PATTERNS AND PRINCIPLES 207 Screening and buffering standards, given the spe- cific use or use intensity proposed in relationship to the nature and density of adjoining uses Maximum lot coverage Minimum lot dimensions and frontage require- ments, including distinction between interior and cor- ner units/lots, pipestem or flag lots, and cul-de-sac lots Maximum number of pipestem lots permitted Lot restrictions regarding inclusion of environmen- tally sensitive areas and utility easements Parking and access criteria, which may include the number of parking spaces required, limitations on F IGURE 12.17 Typical mid-rise and high-rise multifamily housing floor plate. public or private street length, and street loading ca- pacities Maximum building height and methods for calcu- lating height pansive sites, the provisions may include tennis courts, elaborate pool facilities, and exterior exercise and recreation Minimal landscape or tree canopy requirements offerings in a park-like setting. In attached and multifamily housing types, considera- tions may include: Site Design: Residential Development Minimum unit width or size Local zoning codes and planning documents generally pro- vide the principal guidelines and criteria governing residen- Limitations regarding maximum number of units tial development patterns. These include stipulations as to that may be grouped together means and methods for ensuring code compliance. Some Maximum distance between unit entry and parking of the more conventional considerations normally include: Variation in architectural facade and setbacks Maximum permitted density, including means and method of calculation. Density calculations may require Minimum setback from common property lines the omission of all or portions of a site area encum- Minimum distance between buildings bered by environmental constraints such as steep slopes, floodplain, wetlands, major utility easements, Standards and criteria for determining the number and public rights of way and placement of loading and service areas Minimum acreage assembly for select residential Building and fire code requirements types. Often cluster or planned development districts require a minimum amount of acreage to be eligible NONRESIDENTIAL LAND USE for that zoning district Principal nonresidential development in the suburban en- vironment focuses on retail, office, and industrial land uses. Minimum yard requirements, including front, rear, The following discussion highlights the more prevalent and side yard requirements, may be expressed as a building types and site considerations appropriate to each. minimum dimension or relationship to the height of the building Market Considerations Minimum open space provisions, including poten- Provision of retail, office, and industrial development pro- tial distinction among usable open space, dedicated grams can be prompted by a myriad of factors, including open space, and common green space. Ordinances may observation of a demonstrated need for local distribution of discount or cap the amount of public open space al- goods and services at a neighborhood or community level; lowed as part of the project open space calculation. recognition of an opportunity to fulfill a local jurisdictions Similarly, a percentage of the total open space may development goal in expanding either local or regional ec- need to meet certain location, distribution, or perform- onomic base; or recognizing local trends focusing on the ance criteria, such as size, shape, and topographic con- growth, consolidation, or relocation of business ventures siderations, or be exclusive of floodplains, utility within an area. Regardless of the genesis or justification for easements, or wetlands such facilities, site design and site execution must be si- Downloaded from Digital Engineering Library @ McGraw-Hill ( Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website.
  20. 20. DEVELOPMENT PATTERNS AND PRINCIPLES 208 C O N C E P T U A L D E S I G N multaneously sensitive to the requirements of the provider, prospective tenant and patron, site, and surrounding com- munity. Design Considerations As with all land development activity, commercial site de- sign criteria stem from two principal sources. The first con- sists of standards associated with the prospective use. This includes the spatial characteristics and site provisions req- uisite to housing and servicing the facility and its tenants and customers. The second set of criteria concentrates on local land development plans and controls. While the zon- ing ordinance is the primary gauge for establishing site per- formance, other considerations, such as environmental, fire, and safety compliance, factor heavily into facility and site design. This set of criteria may vary among jurisdictions and the nature and intent of the specific land use under consideration. Common Standards. Subsequent to determination that the proposed use is appropriate for a given property, set- back, height, bulk, and other dimensional and performance standards constitute the principal site design criteria. These standards are normally contained in most jurisdictional subdivision and zoning regulations. Floor Area Ratio. Nonresidential development is most fre- quently programmed and sized on the basis of the aggregate square feet of built structure relative to development site F IGURE 12.18 Example of comparable floor area ratios. area. The common method of computation is the floor area ratio (FAR), a method of measurement expressed as the relationship of total building square feet to the total site height to peripheral yard setbacks. If an acceptable angle of area. For example, as shown in Figure 12.18, a 10,000-ft2 bulk plane from the top of building to a given property or building located on a 40,000-ft2 parcel would constitute a parcel line is designated, the setback can increase propor- floor area ratio of 0.25 (building area divided by parcel tionately as the building height increases. For example, a acreage). The number of floors associated with the built required 40 angle of bulk plane might require a 17-ft set- product does not influence the floor area calculation. In the back for a 20-ft high building and a 34-ft setback for a 40- cited example, the 10,000-ft2 building might be constructed ft tall building. Other jurisdictions may express a minimum as a two-floor building of 5,000 ft2 each, or a four-story yard setback based on a given building height and simply building of 2,500 ft2 each. The floor-area-ratio is 0.25 in all stipulate that for every additional foot of building height cases. Most jurisdictions do not include parking structures the setback dimension will increase a set distance. Figure in floor area computations. Similarly, exclusions may in- 12.19 illustrates the concept of angle of bulk plane for reg- clude portions of the building that are below grade or space ulating building height. programmed for select circulation, service, and support fa- Parking, Loading, and Service. Criteria governing mini- cilities. It is important to be aware of the method for cal- mum parking, loading, and service are normally expressed culating FAR in each jurisdiction. in relationship to the floor area of the proposed building Lot Size and Bulk Regulations. Minimum lot size, build- program. Typically, the zoning ordinance stipulates this ing height, bulk, setback, and yard requirements are nor- standard as a minimum number of parking spaces to be mally stipulated in the individual zoning categories for provided on-site, although in some cases a portion of the nonresidential uses. The criteria generally vary in relation parking may be provided off-site or in combination with to the intensity of the desired development and the char- adjacent uses. Jurisdictions vary in terms of how they ex- acteristics of the adjacent land use. Areas designated as press this relationship. It may be based on gross building more urban will normally require smaller setbacks from square footage, net building square footage, net leasable or parcel boundaries. While a maximum building height may tenant area. The designer must understand the method of be stipulated, the permitted height of a structure may be calculation, ascertain the minimum requirement based on governed by performance criteria. A common method of public standards, and ensure that such a minimum provi- control focuses on maintaining a relationship of building sion has client and market acceptance. Unique program re- Downloaded from Digital Engineering Library @ McGraw-Hill ( Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website.
  21. 21. DEVELOPMENT PATTERNS AND PRINCIPLES 12 DEVELOPMENT PATTERNS AND PRINCIPLES 209 RETAIL Retail development may be loosely categorized according to the size and physical characteristics of the proposed facility. The principal types of retail locations include freestanding, strip, center, and mall arrangements of sales and accessory uses. Freestanding The freestanding retail establishment has taken on reduced import in the suburban market, given trends focusing on the aggregation of retail uses and the benefits associated with collective marketing, expanded visibility, and customer capture associated with more encompassing retail or mixed use projects. Where a freestanding retail use does exist, it is generally positioned to respond to several sets of location criteria. It may be an establishment, sited on a separate recorded lot or parcel, that is part of a larger community of like uses, such as a town or village center or in a linear arrangement along a major road or highway. It may consti- tute a modest forerunner retail service in a geographic area of insufficient population concentration to warrant more ex- pansive retail development. It may represent a national or local business with a sufficiently unique market to generate patronage at a location apart from other retail trade or F IGURE 12.19 Illustration of angle-of-bulk plane. whose functional requirements are best satisfied as a free- standing structure. In today’s suburban retail market, freestanding retail es- quirements or marketing considerations often prompt a tablishments are commonly associated with locations within need for parking and loading space provisions to be in ex- or proximate to larger retail or shopping center. Establish- cess of the minimum zoning criteria. ments such as restaurants, banks, movie theaters, bowling Landscape and Open Space. For nonresidential uses, this alleys, gasoline stations, office buildings, and similar sin- is typically expressed as a percentage of the total site area gular operations may be located on separately recorded lots, that is not encumbered with the building, vehicular circu- sometimes referred to as pad sites, within the parking area lation, and parking. While it is normally considered the or along the road frontage of larger retail centers. residual portion of the site remaining for landscaping, in The size and functional characteristics of such establish- some localities it may be more conservatively delineated to ments vary considerably. However, building visibility, the exclude pedestrian walkways, patios, and similar site im- number and convenience of customer parking, and the size provements, which are deemed impervious surface treat- and location of loading and service requirements generally ments. Landscape requirements are generally categorized as represent the primary site design criteria that establish the two main types. pattern for such uses. Where such a facility is contemplated Peripheral yard and buffer area requirements may be at isolated locations, one can anticipate a greater need to stipulated for nonresidential projects, which are deemed in- ensure measures of compatibility with surrounding devel- compatible with surrounding land uses. These may be pre- opment. Integration of freestanding retail uses as an adjunct scribed as a fixed dimensional width with certain pro forma to neighboring strip, center, or mall retail development pat- landscape treatments or as a performance criteria requiring terns generally presents less difficulty in ensuring commu- a combination of plant material and/or structural elements nity fit and may afford advantages to the extent parking, that provide an equal or improved buffering condition. street improvements, and other infrastructure considera- A second set of standards focuses on minimum land- tions may serve multiple users. scape improvements required given specific development program components. These may deal with shielding or Strip Centers screening of parking areas, service and loading zones, min- Strip centers literally represent the aggregation of retail uses imal streetscape standards, foundation planting, parking lot in a linear arrangement, most notably with their front fa- landscaping, or other specific concerns of the local juris- cades paralleling roadways or positioned in an ‘‘L’’ config- diction. uration at the intersection of major transportation routes. Downloaded from Digital Engineering Library @ McGraw-Hill ( Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website.
  22. 22. DEVELOPMENT PATTERNS AND PRINCIPLES 210 C O N C E P T U A L D E S I G N Generally, the establishments are one store deep, share com- standing retail establishments such as banks, gas stations, mon interior walls, and are linked by a common pedestrian and restaurants at the center or along the roadway frontage walkway across the storefronts. The bulk of parking is ag- gives a functional complexity to a retail center and requires gregated into one or more principal parking areas normally careful attention to site details to ensure sufficient visibility, located between the store facade and the street. Strip cen- access, convenience of parking, and service and loading. ters rely on a strong visual relationship to the adjacent street Figure 12.21 represents a typical retail center design. frontage for identity and marketing. Strip retail arrange- ments can vary in size, however, once the linear distance Retail Mall across the collective storefronts exceeds 400 ft pedestrian The distinguishing characteristics of the retail mall include circulation between stores begins to subside. Once a larger the separation of major pedestrian movements from pe- retail establishment, such as a major grocery store or drug ripheral vehicular parking and circulation. Generally store, is introduced into a linear arrangement, the distinc- located between opposing store facades, an internal pedes- tion between strip and retail center becomes less clear. Fig- trian walkway or mall may be either open or under roof. ure 12.20 illustrates the typical strip center configurations. Both arrangements provide an opportunity to direct cus- Retail Center tomers along expanses of intervening retail establishments. A typical mall is presented in Figure 12.22. A normal Finding definitive criteria to distinguish a retail center from convention in organizing on-site vehicular circulation is to a strip center can be difficult, given the negative connota- position a service drive at the building perimeter and a tion that the latter has acquired. Retail centers share in their perimeter road near the outer edge of the major field of reliance on common parking areas, major pedestrian cir- parking. Major approaches to the mall tend to be aligned culation across storefronts, and maintenance of a reasonable with main store anchors. In many instances, freestanding relationship and visibility to adjacent roadways. A distinc- tion can best be found in the number of potential anchor or larger retail establishments that are located in a retail center, an abandonment of sole reliance on a linear arrange- ment for all of the retail establishments, and the introduc- tion of smaller pad site within the retail center site. Centers often are arranged in an ‘‘L’’ or ‘‘U’’ shape, with anchor stores occurring at the building extremities and/or central to the parking lot. These arrangements take advantage of parcel depth, and lining multiple sides of the parking area with stores reduces the distance between the parking stalls and a variety of retail establishments. The introduction of free- F IGURE 12.20 Typical strip center arrangement. F IGURE 12.21 Typical retail center arrangements. Downloaded from Digital Engineering Library @ McGraw-Hill ( Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website.
  23. 23. DEVELOPMENT PATTERNS AND PRINCIPLES 12 DEVELOPMENT PATTERNS AND PRINCIPLES 211 F IGURE 12.22 Retail mall arrangement. uses (pad sites) may occupy acreage between the outer mall parking can assist in reducing distances between parking loop drive and the perimeter street network. areas and retail stores. The resulting site solution often en- Figure 12.23 illustrates the front-sided multilevel park- tails the bridging of peripheral service drives around the ing arrangement employed at the Tysons II retail mall in center perimeter, and in the case of multilevel malls may Fairfax, Virginia. In the background (right rear), parking result in pedestrian walkways that connect to various levels decks have been constructed over former surface park- of the center. ing lots to accommodate the expansion of neighboring Tysons I. Retail Center Design Considerations There is a considerable range in the size of retail malls, Site design for retail centers should be predicated on overall with major regional serving facilities often exceeding 1 mil- customer ease in identifying and locating the individual ten- lion ft2 of leasable area. Increased reliance on structured ants within the center. Convenience of vehicular access, ad- Downloaded from Digital Engineering Library @ McGraw-Hill ( Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website.
  24. 24. DEVELOPMENT PATTERNS AND PRINCIPLES 212 C O N C E P T U A L D E S I G N F IGURE 12.23 Retail mall with structured parking. (Photo by Larry Olsen) equacy and placement of customer parking, and safety of Beginning at the site perimeter, design considerations for pedestrian movements between parking areas and retail es- retail activities should include the following: tablishments are all fundamental site planning considera- Center Orientation to Surrounding Road Network. Retail tions. A secondary set of criteria focuses on the internal establishments should be positioned to take advantage of servicing and operation of the center, particularly in regard visibility to abutting public rights of way. Leasing agents to separation of service, delivery, and loading facilities. Typ- maintain the greatest market asset of a retail center is unob- ically, reasonable convenience of parking areas (to the retail structed visibility from adjacent roadways. In expansive establishment) imposes a limit on the maximum acceptable centers, the major anchors are usually singled out for this distance between the most peripheral parking space and the elevated position, with smaller flanking or interior store lo- center itself. This distance generally approximates 400 ft, cations dependent on foot traffic generated by the anchor. the equivalent of a two-minute walk. There are ample examples of successful retail centers that Downloaded from Digital Engineering Library @ McGraw-Hill ( Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website.