Coupled Human / Biological Systems in Urban Areas : Towards an Analytical Framework Using Dynamic Simulation (Concepts drawn from the NSF-sponsored Urban Trace- Gas Emissions Project) Phillip C. Emmi Professor of Urban and Regional Planning University of Utah November 20, 2003

Presentation Outline Conceptualize coupled human - biological systems in urban areas –Mankind as an ecological force –Energy use and urban density –Population growth, urban land consumption and road- building –A reinforcing feedback loop Simulate urban sprawl and traffic congestion –Reference behavior –Causal loop diagram and system map –Policy simulations –Structure, results, findings and conclusions Future directions

Mankind as an Ecological Force Mankind is now a force of geologic proportions on the surface of the earth. Mankind is now a force for global atmospheric and climatologic change. Within 4 years, we become a predominately urban species: within 30 years, we will be 72% urban. With further density declines, we go from occupying 3% to 8 - 9% of the earth’s habitable surface. We will then be an interconnected tissue across earth’s land surface. We need to think seriously about the use of land and the reconstitution of our atmosphere through urban processes.

Urbanization & Bio-/Atmosphere Exchange

Urban Energy Consumption & Density

Urban Land Development Before & After 1993

Sprawl in a Growing Region ∂(land)=3.3*∂(pop) The Piedmont of the Southern Appalachian Mountains Range of Change in Population and Urbanized Land, Source: Fulton Who Sprawls Most? Brookings.

Sprawl in a Declining Region Ohio, Pennsylvania, West Virginia Range of Change in Population and Urbanized Land, Maximum 2% 53% Minimum -15% 25% Median -5% 38% Source: Fulton Who Sprawls Most? Brookings. Lake Erie ∂(land) = -7.6*∂(pop)

A Reinforcing Feedback Loop (a la Newman & Kenworthy, 1989) Most cities that built freeways found that this spread out urban land use and generated more traffic, until the freeways were congested again. The response was to suggest that still more roads were urgently needed. The new roads were justified again on technical grounds in terms of time, fuel, and eliminating congestion. This sets in motion a self-reinforcing cycle of congestion, road building, sprawl, more congestion and more road building.

Roads Beget Roads: The Cover of Asphalt (April, 1966)

Expectations

Simplified System Map

ITEM SimulationError Urban Population827,0001,184,0001,187, % Urban Land (acres)166,000272,000267, % People/Acre % Road Lane Miles2,8214,6364, % Lane Miles/1000 people % Validation Statistics for SprawlSim, Salt Lake City, UT

Percent Change in Key Variables

Cockpit with Policy Sliders

(1) Baseline, (2) Shock-and-Awe and (3) Cake-and-Eat-It-Too Land Development Densities in People per Acre

Three Scenarios: (1) Baseline, (2) Shock-and-Awe and (3) Cake-and-Eat-It-Too Traffic Congestion as Measured by the Percent Change in the Road Gap

System Structure The interaction between urban land development, trip generation, and roadway construction can be represented as a goal-seeking process nested within a self- reinforcing feedback loop.

System Results This structure gravitates toward a pattern of incessantly more fervent activity in pursuit of an ever-receding goal – increasingly more miles of roadway construction, induced developmental density declines, increased vehicular traffic and more traffic congestion. It gravitates toward an ever-expanding gap between actual and desired results.

Finding #1: Feedback as Force This reinforcing feedback structure is an autonomous force sufficient to cause urban expansion even without an economic or demographic impulse.

Finding #2: Management Requirements Regulating this force is essential for the successful management of cities. –It is key to urban metabolics, thus … –It is key to the dynamic of human- biological systems in cities.

Finding #3: Feedback Dampening Works Dampened feedback scenarios work. –They do so by aggressively shifting travel mode, increasing existing roadway capacities, increasing developmental densities and thus lowering auto trip generation. Defeating sprawl and congestion requires multiple policies aggressively implemented. With that, other beneficial results ensue.

Conclusions A three-fold policy design dampens sprawl. Dynamic simulation facilitates experimenting with alternative policies. This creates a new basis upon which to learn and act. –Highlight critical factors, complex links –Visualize policy explorations –Identify robust strategies –Stimulate discussion among reference groups –Facilitates “steering” of inter-organizational networks

Future Directions Refine the current sector Add further sectors –traffic volume, speed and congestion sector –local fiscal sector –atmospheric emissions sector –urban forest regime sector Continue to engage local policy leaders in group-based modeling