Removing the Blindfold from Economic Development

When a city doesn’t understand its revenue stream in relation to its land use allocation and shelter capacity, it can’t correct deficiencies in these relationships to permanently improve its economic stability. This lack of knowledge eventually produces decline and flight from an expanding core of blight. Decline has now progressed to include portions of surrounded suburbs with inadequate land use activity and shelter capacity correlation. The solution has been sprawl that annexes land to blindly repeat old mistakes. It is slowly consuming our source of life and the blindfold must be lifted. Surrounded suburbs have no option.

LAND USE ALLOCATION

A city’s land use allocation is defined by its zoning map. Its revenue comes from the acres in each zone, the value of the acres, the gross building area available, the activity that is sheltered in the gross building area present, the revenue potential per square foot of activity sheltered, the condition of the shelter, and the specific location of the shelter. The productivity, or financial yield per acre from the zone, is a function of these fundamental factors.

SHELTER CAPACITY, INTENSITY, INTRUSION and DOMINANCE

There are six design categories that produce gross building area. Shelter capacity is gross building area divided by the project acres consumed. Gross building area multiplied by the percentage of project pavement introduced and divided by one acre, or 43,560 sq. ft., produces an “intensity” measurement. The number of building stories divided by five produces an “intrusion” coefficient. An intensity measurement multiplied by an intrusion coefficient produces a “building dominance” measurement.

Building dominance has a shelter capacity component that is occupied by activity. Every taxable activity produces revenue per gross building square foot related to the activity. These values are presently undefined, but activity revenue per square foot multiplied by the gross building area per acre devoted to the activity produces predicted revenue per acre from the activity. The total acres devoted to the activity multiplied by the anticipated revenue per acre produces a total revenue forecast for the acres allocated to the activity. Potential revenue increases as predicted shelter capacity per acre increases, but the trade-off is increased intensity and building dominance that can compromise a city’s quality of life.

PLANNING INTELLIGENCE

Most cities do not know the revenue produced by each zone, census tract, and census block within its boundaries. They cannot calculate the data because they do not know the acres consumed by an activity group, the gross building area occupied by the group,, and the revenue potential per square foot of activity. This means that it cannot calculate the revenue implications that would be produced by increasing or decreasing the square feet of shelter available per acre for a given activity. In agricultural terms, this would be considered lack of knowledge regarding “yield per acre”. It would produce arbitrary crop choices, arbitrary field area allocation, and eventual insolvency.

Most cities have arbitrary zoning plans. They have not understood the options and economic implications of land use allocation and shelter capacity in enough detail to guide their financial future and convince a skeptical public. Their emphasis has been on the separation of incompatible activities. In addition, these cities rarely know their operating, maintenance, improvement, and debt service expense per acre. This means they cannot compare their expense per acre with the average revenue produced per acre, and they cannot produce revenue data in enough detail (by census block, tract, or municipal zone) to evaluate and adjust their economic stability.

When a municipality has completed its city design homework, it will know what its blocks, tracts, and zones are yielding per acre and will be able to compare this performance to its expense per acre. The result will define the current economic balance of its land use allocation plan and form a baseline for future strategic option evaluation.

If a city does not have relevant land use allocation data, gross building area data, and activity revenue per square foot knowledge; it will not have the ability to predict gross building area revenue options per acre. It will continue to waste land and blindly produce urban form that has no relationship to the economic stability required.

Intelligence is needed to prepare strategic plan options with the potential to achieve an economic goal over time. Cities have not pursued the required intelligence and do not have the tools required to predict strategic plans and tactical options that have the potential to achieve an economic goal.

EXPLANATION

I’m going to repeat a section I wrote in “The Density Distraction in City Planning” to provide a little insight into the spectrum of gross building area options that can be produced on a given land area when specification values are modified; and the impact this has on revenue potential. My point is that if a given activity has an estimated revenue yield per square foot, gross building area options can produce a broad range of revenue choices. Keep in mind that the gross building area options presented relate to the G1 Design Category and two sets of fifteen specification values. There are many other specification value choices and five other design categories and specification lists that can be used to expand the options available. Many specification values are not desirable, however, and research is required to convert design intuition to knowledge.

Six parking design categories encompass most of the shelter provided on the planet. They are:

1)      G1: Buildings with surface parking around, but not under the building

2)      G2: Buildings with surface parking around and/or under the building

3)      S1: Buildings with structure parking adjacent to the building on the same parcel

4)      S2: Buildings with underground parking

5)      S3: Buildings with structure parking at grade under the building

6)      NP: Buildings with no parking required

The parking structure options may have supplemental surface parking, but when a parking garage is present, the building is classified by the garage configuration present. These building categories may be occupied by any activity group that complies with local building and zoning requirements.

The point is that shelter classification begins with the parking design category involved, and each category has gross building area limitations defined by design specification decisions. These decisions limit the scope of land use activity and revenue potential that can be introduced.

Table 1 presents a set of optional decisions for the G1 Design Category. They are represented by the specification values entered in the boxes of its Land and G1 Modules. There are fifteen specification boxes and each value represents a design decision that can be adjusted to explore gross building area alternatives. The equations in Col. H of Table 1 convert specification decisions to implications in Col. G. The objective of the algorithm is to distill the core buildable land area available for a building and surface parking plan in cell F32. 

The master equation in cell A37 correlates the core area found in cell F32 with the parking decisions entered in cells F33 and F34 and the floor quantity options entered in cells A42-A51. It predicts gross building area alternatives in cells B42-B51 based on these floor quantity options. The remainder of the Planning Forecast Panel predicts additional implications related to the gross building area options calculated in Col. B using the secondary equations on line 41. Shelter capacity options corresponding to the gross building area options forecast in Col. B are located in Col. F. The entire panel illustrates a few of the many implications that can be forecast as a function of gross building area predictions. Revenue, expense, construction cost, return on investment, population, traffic generation and so on are a few that are not shown.

Table 1 illustrates the many specification decisions required to calculate shelter options for the G1 Design Category. A change to one or more values entered in the boxes of Table 1 would produce a new forecast in Col. B of the Planning Forecast Panel, and hundreds of options could be predicted in less time than it would take to produce one sketch.

The unpaved open space percentage specification in cell F11 of Table 1, and the impervious cover limit calculated in cell F12, represents one of the decision / implication relationships that play a significant role in the calculation of gross building area options. An unpaved open space decision, however, is only one box among many design specifications decisions that combine to determine shelter capacity options.

SEVERAL SHELTER DESIGN PRINCIPLES

Table 1 is based on 40% unpaved open space in the buildable land area. When the gross building area values in Col. B of the Table 1 Planning Forecast Panel are mapped in Figure 1, the results can be expressed in the following terms:

The rate of increase in gross building area declines at an accelerating rate as the number of building floors increase in the G1 Design Category.

Building cover declines more rapidly than gross building area increases because the gross building area permitted per parking space (a) in Table 1 is less than the parking lot surface area planned per parking space (s).

Figure 1 illustrates the dramatically decreasing rate of increase in gross building area as building height increases. Gross building area increases from 38,577 sq. ft. to 59,000 sq. ft., but it barely increases above the five story mark of 55,722 sq. ft. This occurs because gross building area does not increase as rapidly as surface parking area when (a) is less than (s). Expanding parking area for additional spaces is required to justify increased building area, but this eventually reduces the land remaining for building cover to unrealistic levels.

Figure 2 is based on (a) being greater than (s) and 15% unpaved open space being entered in Table 1. Figure 2 shows that gross building area still increases at a decreasing rate, but the results produced are dramatically different because of the specification value changes. Gross building area increases from 85,630 sq. ft. to 186,152 square feet, but gross building area slowly increases above the 5 story mark of 164,673 sq. ft. Parking cover consumes the same amount of land per space, but gross building area per parking space grows more than parking lot area per space. This scenario explains why the gross building area arc increases more rapidly than the building cover arc declines in Figure 2.

When the five story gross building area potential in Tables 1 and 2 is subtracted from the one story gross building area potential predicted, the results expose another G1 design principle. In the case of Figure 1, the total gain for 1-5 stories is 17,145 sq. ft. The total gain for 5-10 stories is 3,278 sq. ft. In the case of Figure 2, the total gain for 1-5 stories is 79,043 sq. ft. The total gain for 5-10 stories is 21,749 sq. ft. This observation produces the following principle.

The most rapid increase in G1 gross building area occurs within a 1-5 story range.

The actual gain from 1-5 stories is a function of all design specification decisions entered in Table 1. Above 5 stories, the gross building area gain per additional floor becomes increasingly less cost-effective.

Figure 2 produces much greater gross building area potential, but is the open space and parking reduction desirable? I won’t attempt to answer the question. I’m simply pointing out an issue that can be accurately measured and evaluated with comparative studies using the language of City Design. In fact, the complete language of City Design can be used to measure existing conditions, evaluate future potential, and accurately define leadership decisions with confidence based on objective measurement and comparative evaluation.

Figures 1 and 2 explain why the gross building area permitted per parking space (a) and the unpaved open space percentage proposed per project (OSAU) are two of the most common points of public and private disagreement. Greater open space and parking requirements reduce potential gross building area, private return on investment, and public revenue per acre, but at what point do the reductions produce excessive intensity in the neighborhood? This cannot be answered without a comprehensive method of measuring and evaluating existing conditions. It cannot be improved without an accurate method of converting measurement and evaluation to accurate, comprehensive, and correlated shelter capacity and revenue potential options.

The G1 design principle behind this section of the essay can be stated in a single sentence.

Every additional surface parking space justifies increased gross building area; but reduces the core land area available for building cover, until the core area remaining becomes too small to accommodate a realistic floor plan.

Figures 1 and 2 demonstrate that gross building area options can be forecast in mathematical terms. When a gross building area option is multiplied by activity revenue potential per square foot and divided by the acres consumed, the result is a yield per acre that can be compared to city’s average expense per acre. When total yield is divided by total acres and compared to a city’s average expense per acre, the results must balance or budget cuts will be required. These cut options often represent unpleasant reductions in quality of life. The objective is to plan shelter capacity, intensity, and activity allocation in a city to establish a stable economy that is capable of avoiding budget cuts. This has the potential to improve quality of life within a limited Built Domain that protects its source of life.

BUDGET CUTS

There will always be those who disagree with the program of services offered by a city and the budget emphasis placed on each. This will lead them to advocate program elimination or budget cuts at the very least. The debate will continue until a community votes on the program of services desired. If a program is adopted, the minimum cost to deliver the service can be debated, but elimination will be removed from the discussion.

We all know that it is possible to pay too little and receive inadequate products and services. The second public debate will surround the minimum cost to deliver acceptable products and services. The bottom line is that a city must pay for a desired program. Let’s dispense with the concept of getting something for nothing. Define what “something” is and get over the concept of getting it for nothing. Focus on the minimum cost to receive an acceptable level of service for an adopted program item. Then a city must develop land use allocation and shelter capacity options that are equal to the current and future expense implied.

A public vote can give a struggling government the program direction it needs to define the average revenue per acre required to afford the program. The government can then focus on creating city design options for public review that have the potential to deliver this revenue.

CONCLUSION

I have written The Science of City Design to explain shelter design categories, activity groups, design specifications, architectural algorithms, master equations, and planning forecast potential. The goal is to introduce a vocabulary and language of city design that can consistently improve the planning results needed to protect a population’s quality of life within a limited Built Domain that protects its source of life – The Natural Domain.

The Density Distraction in City Planning

Density is a social statistic. It cannot lead the formation of shelter for human activity within urban areas. It has caused confusion, contradiction, disagreement, and conflict within and between those in the public and private sectors; but it is now possible to replace the statistic with a language that can accurately measure the past, evaluate the present, predict the future, and define decisions in terms that have the accuracy needed for leadership direction. In order to make my point, I need to introduce the language, illustrate its leadership potential, and compare it to the performance of density statistics.

INTRODUCTION TO THE LANGUAGE

Gross building area is a fully enclosed square foot area that can be occupied by any activity. Shelter capacity is the gross building area that can be constructed per buildable acre available, and there are many options. The amount of gross building area provided per acre, in addition to the supporting pavement introduced, is referred to as a level of “intensity”. Intensity is moderated by the amount of unpaved project open space that remains. At one end of the spectrum is a small building on thousands of ranch acres. At the other is a high-rise building on a fraction of an acre. In both cases, the square feet of shelter and pavement constructed consume land that is a natural source of life.

Activity is referred to as “land use”. The relationship of shelter capacity and activity to geographic location affects economic stability and public acceptance. In other words, shelter capacity, condition, and location produce levels of physical intensity, social activity, and economic contribution that affect our quality of life within any urban area.

The Movement, Open Space, and Life Support Divisions of our Built Domain consume natural land to serve a Shelter Division that adds to the consumption and is sprawling without restraint. The square feet of building area and pavement introduced per acre determines the population and activity that can be served, as well as the physical intensity introduced. The social open space that remains contributes to the external quality of life provided. In other words, the physical, social, and economic characteristics of intensity not only affect the health, safety, and welfare of a population within The Built Domain; but the survival of its source of life beyond. We must begin to understand these relationships.

Six building design categories encompass most of the shelter provided on the planet. They are:

1)      G1: Buildings with surface parking around, but not under the building

2)      G2: Buildings with surface parking around and/or under the building

3)      S1: Buildings with structure parking adjacent to the building on the same parcel

4)      S2: Buildings with underground parking

5)      S3: Buildings with structure parking at grade under the building

6)      NP: Buildings with no parking required

The parking structure options may have supplemental surface parking, but when a parking garage is present, the building is classified by the garage configuration present. These building categories may be occupied by any activity group that complies with local building and zoning requirements.

The point is that shelter classification begins with the building design category involved, and each category has gross building area limitations defined by design specification decisions. These decisions limit the scope of land use activity and revenue potential that can be introduced.

LEADERSHIP POTENTIAL

Table 1 presents a set of optional decisions for the G1 Design Category. They are represented by the specification values entered in the boxes of its Land and G1 Modules. There are fifteen specification boxes and each value represents a design decision that can be adjusted to explore shelter capacity alternatives. The equations in Col. H of Table 1 convert specification decisions to implications in Col. G. The objective of the algorithm is to distill the core buildable land area available in cell F32.

The master equation in cell A37 correlates the core area found in cell F32 with the parking decisions entered in cells F33 and F34 and the floor quantity options entered in cells A42-A51. It predicts gross building area alternatives in cells B42-B51 based on these floor quantity options. The remainder of the Planning Forecast Panel predicts additional implications related to the gross building area options in Col. B using the secondary equations on line 41. Shelter capacity options corresponding to the gross building area options forecast in Col. B are listed in Col. F. The entire panel illustrates a few of the many implications that can be forecast as a function of gross building area predictions. Revenue, expense, construction cost, return on investment, population, and traffic generation are a few that are not shown.

Table 1 illustrates the many specification decisions required to calculate shelter options for the G1 Design Category. A change to one or more values entered in the boxes of Table 1 would produce a new forecast in Col. B of the Planning Forecast Panel, and hundreds of options could be predicted in less time than it would take to produce one sketch.

The unpaved open space percentage specification in cell F11 of Table 1, and the impervious cover limit calculated in cell F12, represents one of the decision / implication relationships that play a significant role in the calculation of shelter capacity options. An unpaved open space decision, however, is only one of many design decisions that combine to determine shelter capacity options.

Open Space

It’s easy to overlook open space because its value to our quality of life is currently a function of subjective opinion, and this opinion can reduce private return on investment. It is an inevitable conflict, but one open space decision has already been made that is unrecognized by most.

Unpaved open space protects storm sewer capacity from excessive runoff. Storm water runoff is produced by impervious cover and re-directed by storm sewer capacity. Capacity is expressed as the percentage of impervious cover that can be accommodated by a given pipe size. Subtracting this percentage from 100 yields the amount of unpaved open space expected, unless more intricate civil engineering solutions are introduced. A greater pipe size can accommodate a greater percentage of impervious cover, but the pipe cost increases as well. A developer often attempts to minimize cost by minimizing pipe size. This reduces the impervious cover percentage that can be accommodated, but the limit is often over-looked by decision-makers for any number of reasons. If an impervious cover limit is exceeded by many along a branch storm sewer line, unpaved open space declines and flooding is an inevitable consequence, unless detention solutions are introduced. Flooding can easily occur when a community does not know the impervious cover capacity of each branch line in its storm sewer system and approves building and pavement additions over years based on the assumption that growth is good. Unfortunately, the unpaved open space percentage required to protect storm sewer capacity may not be adequate to protect the neighborhood’s quality of life.

Shelter Capacity and Intensity

The gross building area options forecast in Col. B of the Planning Forecast Panel of Table 1 were used to produce the shelter capacity options in Col. F and the intensity options in Col. G. These intensity levels are like the first blood pressure readings. I can only hope that continued measurement and evaluation will produce intensity knowledge and parameters that can lead to an improved quality of life.

Intensity options are produced by values entered in a design category specification template. A leadership decision is taken by defining the design category and specification values adopted for a given location.

Design category choices and specification decisions have gross building area implications. Gross building area divided by buildable land area is shelter capacity. The ability to accurately define gross building area options with a design category master equation makes it possible to predict many implications that are functions of the square foot options predicted.

Urban Form

Building arrangements are often referred to as massing compositions. A collection of compositions is referred to as urban form. Ideally, a plan for urban form allocates the Shelter, Movement, Open Space, and Life Support Divisions of The Built Domain to serve growing populations within geographic limits that protect their quality and source of life – The Natural Domain.

Master equations make it possible to measure, evaluate, diagnose, and prescribe urban form one project at a time. When a Built Domain is geographically limited, the quality of life within these limits will be a function of the design categories and specification values chosen to create urban form. Our quality of life is affected because we must live within and among the buildings, pavement, spaces, and movement systems we create.

Several Shelter Design Principles

Table 1 is based on 40% unpaved open space in the buildable land area. When the gross building area values in Col. B of the Table 1 Planning Forecast Panel are mapped in Figure 1, the results can be expressed in the following terms:

The rate of increase in gross building area declines at an accelerating rate as the number of building floors increase in the G1 Design Category.

Building cover declines more rapidly than gross building area increases because the gross building area permitted per parking space (a) in Table 1 is less than the parking lot surface area planned per parking space (s).

Figure 1 illustrates the dramatically decreasing rate of increase in gross building area as building height increases. Gross building area increases from 38,577 sq. ft. to 59,000 sq. ft., but it barely increases above the five story mark of 55,722 sq. ft. This occurs because gross building area does not increase as rapidly as surface parking area when (a) is less than (s). Expanding parking area for additional spaces is required to justify increased building area, but this eventually reduces the land remaining for building cover to unrealistic levels.

Figure 2 is based on (a) being greater than (s) and 15% unpaved open space being entered in Table 1. Figure 2 shows that gross building area still increases at a decreasing rate, but the results produced are dramatically different because of the specification value changes. Gross building area increases from 85,630 sq. ft. to 186,152 square feet, but gross building area slowly increases above the 5 story mark of 164,673 sq. ft. Parking cover consumes the same amount of land per space, but gross building area per parking space grows more than parking lot area per space. This scenario explains why the gross building area arc increases more rapidly than the building cover arc declines in Figure 2.

When the five story gross building area potential in Tables 1 and 2 is subtracted from the one story gross building area potential predicted, the results expose another design principle. In the case of Figure 1, the total gain for 1-5 stories is 17,145 sq. ft. The total gain for 5-10 stories is 3,278 sq. ft. In the case of Figure 2, the total gain for 1-5 stories is 79,043 sq. ft. The total gain for 5-10 stories is 21,749 sq. ft. This observation produces the following principle.

The most rapid increase in G1 gross building area occurs within a 1-5 story range.

The actual gain from 1-5 stories is a function of all design specification decisions entered in Table 1. Above 5 stories, the gross building area gain per additional floor becomes increasingly less cost-effective.

Figure 2 produces much greater gross building area potential, but is the open space and parking reduction desirable? I won’t attempt to answer the question. I’m simply pointing out an issue that can be accurately measured and evaluated with comparative studies using the language of City Design. In fact, the complete language of City Design can be used to measure existing conditions, evaluate future potential, and accurately define leadership decisions with confidence based on objective measurement and comparative evaluation.

Figures 1 and 2 explain why the gross building area permitted per parking space (a) and the unpaved open space percentage proposed per project (OSAU) are two of the most common points of public and private disagreement. Greater open space and parking requirements reduce potential gross building area and private return on investment, but at what point do the reductions produce excessive intensity in the neighborhood? This cannot be answered without a comprehensive method of measuring and evaluating existing conditions. It cannot be improved without an accurate method of converting measurement and evaluation to accurate, comprehensive, and correlated leadership expression. A new language of city design is needed. I’ll get to this in the final section of this essay.

The G1 design principle behind this section of the essay can be stated in a single sentence.

Every additional surface parking space justifies increased gross building area; but reduces the core land area available for building cover, until the core area remaining becomes too small to accommodate a realistic floor plan.

Figures 1 and 2 demonstrate that planning and design issues can be expressed in mathematical terms. This has the power to persuade in a political environment of conflicting opinion. It also improves our ability to collaborate with the science of others; since the land our planet can donate to shelter, and the shelter capacity of this land, is becoming an issue of survival. The answers we find will be reflected by the context, composition, and function of urban form. The appearance of these solutions will symbolize our progress toward the symbiotic correlation of Shelter, Movement, Open Space, and Life Support within a geographically limited Built Domain that protects our quality and source of life – The Natural Domain.

COMPARISON TO DENSITY

Density is a statistic that indicates the number of residential dwelling units provided or permitted per acre of land occupied. The gross building area potential of the land given the combined effect of all zoning regulations is ignored because accurate calculation has been elusive, but feasibility is a function of the relationship between dwelling unit quantity, unit area, and gross building area potential. A density statistic cannot provide the correlation required for adequate leadership.

Table 1 has illustrated the correlated design specification items, topics, and master equation that produce gross building area options per buildable acre for the G1 Design Category. A feasible density is one that multiplies dwelling unit area by quantity to fit within the gross building area potential of a given land area. Density does not lead to the gross building area potential of land. It is limited by the specification decisions that determine gross building area, and unachievable density regulations or goals simply introduce confusion and frustration.

Density is oblivious to the inter-active design specification decisions in Table 1, but they determine gross building area potential and intensity implications for any given land area. It is also oblivious to the various dwelling unit area decisions that can increase or decrease density within gross building area potential. The conflict between ambiguous density regulation, uncorrelated zoning regulation, and the gross building area potential of land is often inevitable.

CITY DESIGN

The creation of urban form begins with an ability to predict gross building area capacity, intensity, and activity options for every land area and location within the geographic area defined.

Our current inability to correlate the realistic gross building area potential of land with the activity permitted and quality of life desired produces confusion, conflict, and suspicion that can only be resolved with opinion and compromise. This often produces arbitrary decisions and unsatisfactory results that assemble over time.

The gross building area options produced by correlating the design specification decisions in Table 1 could not have been produced by an independent density statistic. The observations produced by charting the Table 1 options in Figures 1 and 2 would remain unknown or intuitive at best. There are just too may design decisions involved that affect and precede density calculation and can’t be led by a density statistic. It is not a credible minimum design standard capable of consistently leading shelter capacity toward urban form capable of increasing capacity and improving our quality of life. It is a rear view mirror, not a heads-up display of options and opportunities.

I have written The Science of City Design to explain design categories, activity groups, design specifications, architectural algorithms, master equations, and planning forecast panels. These topics introduce a vocabulary and language of city design that can consistently improve planning results by correlating the decisions required to shelter growing populations within a limited Built Domain. The goal is to protect this population’s quality and source of life.

For those interested in pursuing the study of city design, urban form, and its physical, social, psychological, environmental, ecologic, and economic implications; The Science of City Design can be found at Amazon.com in e-book and paperback versions.

THE HUMAN SCALE

The search for a scale that can measure the level of pressure imposed by shelter, movement, open space, and life support within the projects, neighborhoods, and districts of our urban world continues. I believe this human scale has at least five measureable components; and that they combine to give an initial indication of urban health within the urban anatomy. These factors and terms are relatively unknown, so let me begin with an explanation.

CAPACITY

Shelter capacity (SFAC) is the gross building area (GBA) in sq. ft. provided per buildable acre (BAC) to shelter any activity. We tend to refer to buildings by the activity within, such as a bank building; but a building can be remodeled to suit many activities. The significance of the building is the amount of land it consumes per thousand sq. ft. of gross building area, since this is land removed as a source of life.

SFAC = GBA / BAC

INTENSITY

Building capacity is a measureable factor that can be multiplied by a surface pavement percentage to produce an intensity measurement, but the impact of the measurement must be evaluated in addition to three other factors that combine to affect our physical, social, psychological, environmental, and economic quality of life. Like the first blood pressure readings, however, these measurements will have little meaning until evaluated correlated within a database of accumulated research.

Shelter capacity produces building mass. In this context, the first sentence in this section can be rewritten to say that the product of building mass times the percentage of impervious pavement present in a buildable land area is a measurement of physical intensity. Building mass is represented in this context by a massing ratio equal to shelter capacity per acre (SFAC) divided by one acre in sq. ft. to make the calculation a manageable statistic. In mathematical terms:

MAR = SFAC / 43,560

INT = MAR * IMP%

The Theory of Relative Intensity

A range of potential building mass values has been placed along the y-axis of Table 1, but the ratios do not indicate the impact of related two-dimensional pavement. Impervious cover ratios are represented in ten percent increments of buildable land area along the x-axis to complete the matrix. When an impervious cover percentage is multiplied by a massing ratio, the result is a level of intensity within a given buildable land area (BLA). Table 1 presents the entire range of shelter intensity options available to planners, architects, and designers in a single table. The fact that a value is in the upper left hand quadrant of Table 1 does not automatically mean that it is desirable, however. Table 1 simply defines the entire spectrum, and many options are undesirable. The challenge is to measure, evaluate, identify, and locate existing success and failure within the table.

Shelter capacity is produced by six shelter design categories that can be occupied by any permitted activity. These categories comprise the Shelter Division of The Built Domain and are listed Table 2. Three examples of the residential activity group are shown below these design categories to illustrate the relationship between a design category and an activity group. The classification illustrated is part of the language needed to pursue the science of city design, and begins with the recognition that there are two worlds on a single planet: The Natural Domain and a Built Domain that contains Shelter, Movement, Open Space, and Life Support Divisions.

A lot, parcel, or land area of any size often contains shelter capacity and intensity occupied by activity, except when vacant. Most land area also produces revenue per acre. The revenue offsets a city’s average annual expense per gross acre. If the land area’s revenue is above the municipal revenue target per acre, it subsidizes others. If it is below, it must be subsidized. If there is a budget deficit, budget cuts are considered and annexation is pursued when feasible. The effort is based on the assumption that new revenue will solve the budget deficit. This assumption cannot be tested because the economic productivity of a city’s land use allocation plan cannot currently be evaluated in most, if not all, jurisdictions; and it cannot be adjusted without excessive conflict in many cases. This often produces annexation of unoccupied land that represents new revenue when converted, but repeats old mistakes as the cost of services, maintenance, replacement, and capital improvements increase with age to exceed the new revenue produced.

Informed annexation and land use allocation can only occur when there is a mathematical ability to correlate the shelter capacity options for land with the economic yield implied by potential activity per buildable acre. When correlation becomes feasible, land use allocation, capacity, and intensity options for economic security will become a subject of digital planning and evaluation. The knowledge gained will give planners the credibility to persuasively debate the issue and pursue new revenue that is not based on old assumptions, opinions, and mistakes.

INTRUSION

Intrusion (INTR) is a calculated value used in a building dominance calculation (DOM). It is building height in floors (f) divided by five to avoid the unwieldy calculations produced by skyscraper heights. (When there are two or more buildings in the same project area, varying heights must be weighted to reflect the composition.) Intrusion is introduced as a calculation because a taller building is considered to be more intrusive when all other site planning topic values are equal.

DOMINANCE

Shelter dominance (DOM) is the sum of shelter intensity (INT) and intrusion (INTR) within a project, neighborhood, or district. In mathematical terms:

DOM = INT + INTR

When the constituent topics of intensity and intrusion equations are substituted in the dominance equation above, it becomes:

DOM = ((SFAC / 43,560) * IMP%) + (f/5)

In more general terms, shelter dominance within a project, neighborhood, or district land area is a function of: (1) the buildable land area available; (2) the gross building area constructed; (3) the percentage of buildable land area occupied by impervious cover; and (4) the building height introduced.

Table 3 has been created to illustrate the spectrum of potential building dominance options. Intensity options are arranged along the y-axis and intrusion options are arranged along the x-axis. Adding the two options produces a matrix of dominance values that represent the spectrum of design options available, and not all are desirable. The challenge is the same as that presented by the intensity matrix in Table 1. Existing success and failure must be measured, evaluated, identified, and located in the table.

IMPACT

Impact is the correlation of traffic with shelter dominance in an urban area. A traffic ratio (TRR) is equal to the average daily traffic (ADT) in a neighborhood block divided by 1,000 to make the statistic manageable. Impact is measured by adding a shelter dominance measurement to a traffic movement statistic. In mathematical terms:

TRR = ADT / 1,000

IMPACT = DOM + TRR

IMPACT = ((SFAC / 43,560) * IMP%) + (f/5) + (ADT/1,000)

In other words, if you can calculate shelter capacity and impervious cover, you can calculate the shelter intensity present on a given buildable land area. If you know intensity and building height, you can calculate building dominance. If you have calculated building dominance and know the average daily traffic present or predicted adjacent to the land area, you can calculate physical impact. (A larger number indicates greater impact.)

An impact measurement includes capacity, intensity, intrusion, dominance, and movement statistics. The spectrum of possibilities represents a graduated human scale that can indicate the health of an urban area in relation to the surrounding activity present. The actual spectrum raises a fundamental question for further research:

What impact limits are needed to protect our physical, social, psychological, environmental, and economic quality of life within a geographically limited Built Domain that is economically stable and ecologically symbiotic?

Answers to this question will begin to define the context, composition, pattern, and appearance required to protect a growing population’s source and quality of life. Answers must be found because Mother Nature simply does not compromise with ignorance.

POTENTIAL

The decisions we make concerning the shelter capacity of land is a first tier consideration. It affects the composition, context, and capacity of the cities we inhabit and the scope of land removed from its symbiotic purpose. The activity that takes place within shelter capacity, and the surrounding relationship of these activities, varies as building occupancy changes. This physical and social equation adjusts at a very slow pace, but we have enough experience to know that they can affect a city’s psychological, environmental, and economic vitality when they cannot be forecast to prevent a declining quality of life.

Up to this point the discussion has focused on the measurement of existing conditions. The objective, however, is to learn from these conditions; to repeat success; and to avoid failure. This means that we must be able to use the knowledge gained to lead future policy, strategy, tactics, and performance. Table 4 is included to explain how this can be accomplished using the G1 Design Category as an example.

The G1 Category includes all buildings with surface parking around, but not under the building. It seems to be the most popular shelter category in use today, and is occupied by a wide range of activities with an equally wide range of economic potential. The purpose of this example is to demonstrate how shelter capacity options for a given land area can be accurately predicted. This forecasting potential is the key to strategic city design evaluation and decisions that can be specified with the item values adopted in a design category forecast model.

In other words, shelter category and capacity decisions come first. They establish the composition and context of an urban pattern that must be designed to protect our quality of life. Occupancy determines the economic potential of the shelter resource provided.

Gross land area is given in cell F3 of Table 4 and shelter capacity options (GBA) are predicted in Column B of the Planning Forecast Panel based on the building height alternatives in Column A. The values entered in the boxes of the table represent the design decisions that were correlated to produce the forecast. This template should make it clear that a single value cannot hope to lead to the results predicted.

A change to any value in any box of the template would produce a new forecast. The values predicted in Columns C-G of the Planning Forecast Panel are functions of the shelter capacity predictions in Column B. They are a small sampling to the predictions that can be made once the shelter capacity options in Column B can be forecast. For instance, construction cost, population, traffic generation, and the economic implications of occupant activity are just a few of the predictions that are a function of the square foot options forecast in Column B of the Planning Forecast Panel.

The values entered in the template specification boxes of Table 4 represent a definition of human scale. There are 15 specification boxes and 10 building height alternatives that can be evaluated for a total of 25 optional design decisions. Measured values from an existing project could also be entered in these boxes for evaluation. The intensity levels calculated in Column G of the Planning Forecast Panel present the implications associated with these decisions. They are like blood pressure readings without a frame of reference, however. The condition of the patient cannot be placed in perspective.

At the present time Table 4 represents potential. It is not an answer but part of a vocabulary and language that can be used to search for graduated levels within a human scale that will protect our quality and source of life. I won’t discuss Table 4 and its design category companions in greater detail because they are covered in my new book, The Science of City Design. It is available in e-book and paperback from Amazon.com. The book is my attempt to expose the potential to define human scale in terms that can define past decisions and lead to a symbiotic future.

THE SYMBIOTIC IMPERATIVE

When the architect Louis Sullivan mentioned that form follows function he was actually referring to a fundamental organic principle, in my opinion. His student, Frank Lloyd Wright, adopted the concept and referred to “organic architecture”. I believe they were both pointing to a symbiotic imperative that they could only express at the time with fine art. I’ll repeat Sullivan’s poem here and let you draw your own conclusions.

"It is the pervading law of all things organic, and inorganic,

of all things physical and metaphysical,

of all things human and all things super-human,

of all true manifestations of the head, of the heart, of the soul, that the life is recognizable in its expression,

that form ever follows function. This is the law."

Louis Sullivan, 1896

The phrase “form follows function” was interpreted during the Industrial Period to mean that the function of an invention is reflected by its form and appearance, but this led us to overlook the symbiotic imperative that rules our presence on the planet. It would not have been so easy to overlook if the last line in Sullivan’s poem had read, “that form ever follows (symbiotic) function. This is the law.” We began converting and consuming the land with our inventions, and recognized that the forms and objects we created were a function of the purpose we defined. It was easy to assume that we took precedence over the symbiotic imperative until ecological failure began to appear.

We will not correlate our presence on the planet with its symbiotic imperative overnight, but I believe most of us recognize that we cannot consume the planet with a blanket of sprawling pavement, or co-opt its natural functions, and survive. The form of shelter capacity, intensity, and dominance is one issue. It affects our ability to live within a limited Built Domain that protects our quality and source of life – The Natural Domain. The symbiotic function of The Built Domain is a separate issue. Both must be solved. There is no option. This is what Sullivan meant when he said, “This is the law”. Cities will not flower until they build symbiotic roots. The human scale is a contribution to the growing number of tools that can be used to build knowledge and lead city design toward the goal.