Transportation folks can tell you what percentage of your life is spent on a highway, and provide disturbing evidence on negative impacts, such as the provocation at the conclustion on “roadkill,” a reflection on Central Park, and a look at the nation’s rivers as one way to see a green space network of enormous importance. We all make mistakes and therefore seek manipulations of the physical world to end the repetition of destructive results. The presumption is the United States is covered with smooth, maintainable routes to the 99.9 percentile of need. So now what?

Conception Point

Highways produce the special formula known as the VMT for vehicle miles traveled that measures and sustains economic viability, or as planners accept as reliable without having to look it up. Since the beginning of modern civilization, the VMT formula and all that comes with it have gone unchallenged. The need for a unique balancing formula with similarly powerful economics is now apparent. In the re-implementation of the highway, a counterforce such as the green space network or GSN. It will provide the groundwork that envisions the urban world as a thing outside of the Natural.


Suppose the policy and resources initiated by the National Defense Highway Act have completed its mission in slamming four, eight, and twelve-lane highways through a city and across the nation. Could an equally powerful program work to improve the availability of defragmented natural green space separated from urban regions to form an open space network that would stretch across the country?

Inception point of the institution

The answer is yes, but not without something equivalent to the VMT.1 What could establish a similar level of induced demand? VMT’s simple mathematical formulas yield large public revenue streams, gob-smacking general budget directors, planners, governors, developers, automakers, and so on into mad-max road fans. The land-use opportunities of “a road” is irresistible to money makers and nation builders, but like I said. We’re done, and the residual momentum has become dangerous.

Modes Make Space

Like all communication systems, as the demand for speed increases, it also adds friction plus the cost of deterioration. On the positive side, the answer is built right into this infrastructure. The formula for the VHT (Hours Traveled) leads to VHD (Hours Delayed) then an annual computation of annual average speed. Removing the need to move produces the highest speed.  Among many other possible variables, the question asked here regards the possibility of a fully Natural world encircling the urban system in the century it took to build the National Highway System (NHS). Is that too “Zen?” A decade of highway stupidity is from PIRG (here).

A region’s economy has non-basic businesses that export something in trade for something else. The basic industries have a primary role in making things for immediate consumption, including importing things people want. The mix overlaps to produce vast streams of cars, trucks, planes, ships, and trains moving around the earth to make that happen, and as we all know, things in motion tend to stay that way.

How would a green space formula as powerful as the VMT work? Would it assure access for food businesses, water conservation, active recreation, or Nature’s natural quiet? The economic procedure could invent a claim to a wilderness got these and a thousand other purposes with a green space network. Financing it could retain the owners of this network with a responsibility to sustain natural cycles.

Miles 1992 to 2008 in billions.

The motivation to allocate funds for preservation could be the same as that for armament and security. It would serve a similar purpose and act as a step to assure the containment of all other space within an urbanizing sphere where energy use is identified and skillfully re-purposed toward renewability.

Green Space Network

Building a green space network (GSN) begins as reverse engineering of the VMT. It will be used to accomplish the urban world’s containment with high-speed, low energy links to all of its other dense parts. The GSN will stimulate a level of open space integration by assigning a value to the stress created by isolating green space sections. The cost of this stress is a central unknown, but it is never too late to be made known in order to diminish unsustainable rates of increasing induced demand.

The graphs soar upward on VMTs Daedalus Wings

Adding up all costs can be accomplished. Compile the homes lost in a wildfire or species disruptions that lead to the destruction of a food source. Include the failure to eliminate the rise of ocean toxins such as red tides and other human causes of biome failure.  At present, the list is growing, yet the impacts are deemed absorbable. The mantra “it will be OK, we can rebuild, recover, restore” stays in the heart until it comes at a cost as intolerable as gasping for air when there is none. The reason is silent here, what can be done?

The function of a park is distinguished from the wild as it must be subject to some form of management. A measure of “irrevocable public value” for the wilderness requires a more forceful injection of a classic economic principle and applied to land use policy, “a dollar saved is a dollar earned.” It is the balance required amidst “the dollar invested requires a return.” The question then becomes “when” with a time value.

New Priorities

VMT formulas prove “more roads more revenue” and point to the value of a GSN in one way.  An example occurred in Providence, Rhode Island, when a federal and state highway project announced plans to relocate (not remove) Interstate I-95 in November 2009.2 The I-95 highway ran through downtown Providence. Moving the route produced about 20 acres of highly valuable urban land for dense development. The financial analysis that included long-term savings found the value nearly equaled the cost of moving and rebuilding I-95. (see IWay)

As engineering mastery is spurred on by marvels such as the Panama Canal construction it includes mega-proposals such as fill in, dam, and cover the Hudson River to link New Jersey to Manhattan. In the 1970s, the Woonasquatucket and Moshassuck Rivers’ course was altered merely to achieve an urban design purpose.3 Put the engineering exuberance and life-cycle cost critique aside for a moment. The containment and integration of an encompassing and inviolable open green space network is the missing cautionary element. Using the GSN with an equivalent power approach brings urban containment within the engineer’s reach in solving the core problem of fragmentation. Property is worth more the sooner it is received.

Fragmentation is the opposite of connectivity. While human connectivity has been continuous, stopping the destruction of biodiversity as the ultimate form of “connectivity” has only recently been recognized as having value. The information needed for an active policy of an unfragmented green space network (GSN) is developing with global and national data. Two components that humans fear and love immensely – fire and water provide the power for change. Fire doesn’t feed us like the ocean and the earth or fill our lungs with clean air; it warms us and cleanses us with its fury. That is it.4

Fire is the first issue to resolve in establishing a path to the GSN. Water is examined in another section of this discussion. The most advanced social and physical science for defining fire occurs in the United States West and southwest. Drought conditions combine with the explosive demand for housing in the woods. Despite multiple warning signs, settlements continue to locate in drought/fire locations. Marc Reisner outlines this story in Cadillac Desert. His examination of the horrors of drought and power speaks to the tragedy of the commons. John Fleck’s observations of Water Is for Fighting Over and Judith Schwartz’s Water in Plain Sight, on the other hand, outlines the quality of innovation forced by Nature’s own game of Prisoner’s Dilemma (See #WaterOptimism).

The Wilmer and Aplet (WA) and the Radeloff, Hammer, and Stewart (RHS) methods prioritize wildfire risk. Each aims to develop mitigation efforts mainly based on fuel management—places where housing and dry vegetation overlap have Wildland Fire Maps.

4.2 million acres burned in 2020.

Other plans include U.S. census housing data with the National Land Cover Data (Vogelmann et al. 2001). These resources characterize vegetation with some variation to illustrate the wildland-urban interface (WUI). The housing density threshold is low at one unit per 40 acres, including census blocks with more than 50 percent wildland vegetation.5 Not surprisingly, the Southwest and Northwest show the highest wildland fire potential in the United States and matters most at the WUI. The communications environment on this issue will range from NFTA’s advice and detailed mapping platforms for data sharing and planning by organizations such as ResearchGate and DataBasin that focus on the scientific challenges and natural resources.

The 4.2 million acres burned in 2020 is more than the three previous years combined and were the most significant fires in California since 1932, with a cost of over $2 billion and the destruction of over 10,000 buildings. (Wiki) The research is in a cost well researched, however, the land uses will not change. Live, Die, Repeat appears to be the official land-use policy. (Exceptions)

Road Kill

The federal construction of the highway system defers the cost of management and maintenance to localities. Unknowns such as the need for wildlife crossings to promote conservation and motorist safety arose on a mountain of roadkill and billions of dollars in human costs.6

Here is an example, the wildlife-overpasses in Banff National Park, Canada, illustrate the complexity of filters. Four overpasses cost $11M in 2009. As a result, the quest for a lower cost over/under bridging solution stimulated a design competition for a site in Colorado.  See for an in-depth discussion of results from Animal Road Crossing (ARC).

  • Roadkill
Watch this Film: Bear 71. YouTube two minutes. (here)

If you have a chance to watch this interactive piece (here), know that it will change you. Leanne Allison (co-creator) of Bear 71 is interviewed (here) (Flash HTML5 2020). In November 2020, continuing proof of a fledgling GSN is described as a fifty by 320-foot highway overpass in Utah. It was developed with data on migratory patterns. As in Bear 71, wildlife data can draw the lines around useful  It has become extremely well used according to Smithsonian Magazine (Theresa Machemer, writing (here) and Atlas Obscura (here) and video of the Parleys Canyon Wildlife Overpass (here).

At the heart of the wild urban interface stands a request for a green space network design solution. When coal-smoke choked 19th c. Glasgow, the city, promoted parks to be “lungs of the city.” Urban gardens from food to play throughout the world have become a land use necessity because they meet needs other than food. One of them is expressed by the world-famous Central Park of New York City. It is often used as an early example of the value created by designing a wildlife urban interface. It is not enough as the following account suggests.

A Central Park Story

The Central Park Conservancy (CPC) once had a “billboard” advertisement by the park’s entrances that read, “We have 26,000 trees, and none of them grow money.” While advertisements at park entrances are controversial and banned within the park, the revenue from Central Park’s real estate partners at its perimeter venues is vast. Yet, it fails to meet the conservancy’s charitable purposes as it works diligently to stretch the public purse beyond this signature space. It works but not well; here is an example.

A city appraisal assigned a $19 million value to a restaurant name. It was the Tavern on the Green named by Robert Moses in 1934.7 The leaseholders closed the restaurant and then sold off its labeled bits and parts rather than litigate the royalty. The now Covid-Closed restaurant remains of the controversy are forgotten and not mentioned in its own history (here).

The CPC was formed because deep across-the-board cuts in the city park budgets are easy compared to cutting almost any other public service. When compared to other city parks, CPC’s financial proceeds are controversial. Debates on privatization and economic fairness become strident. However, there is an equally compelling point about an implied responsibility for the management, maintenance, and stewardship of 26,000 trees. Taking responsibility for managing “the wild” now captured in our cities as parks is a product of design and urban life. The system requires many public and private accountability levels, and it took nearly 30 years to build the CPC as an institution. Today, it runs the best-managed park in the country. On the other hand, it is an absolute absurdity to think this approach would be viable as a policy for application to the national open space landscape outside of major urban centers.

To preserve a natural environment, stay away far enough to allow naturally occurring events such as fires or predation to be something that happens in the wild. Natural does not mean nice. When a squirrel hunting fox shows up in Central Park, the CPC must capture and remove or kill it. The possibility of an urban fox might exist, but not without a radical change in how urban design constructs and values open space or parkland. A falcon, on the other hand, can have that squirrel.

The Rivers

USA Rivers
Thousands of River Miles for Westward Expansion

Natural open areas are much more than a “value-added” component to real estate as NYC’s central park illustrates. In 2009, former Secretary of the Interior Ken Salazar thought to reach out to urban dwellers in the hope of developing a more aggressive constituency seeking to expand green open space. He began his efforts in a relatively safe place to do so, St. Louis.

St. Louis’ Gateway Arch is a well-known national park.8 A six-lane highway separates the Gateway Arch parkland from its river waterfront. The initial strategy is direct, expand the idea of National Parks beyond Yellowstone and Yosemite, and focus directly on urban dwellers. Get localities to focus on the economic benefits of road reduction, diverse uses, and natural landscapes, and above all else press for added protection from the well-known capacity for the Mississippi River to flood.

The River GSN

In 2010 Michael Van Valkenburgh and his team won an international design competition to connect Arch with Grenchen on the river. See the design solution here. The Museum of Westward Expansion is below the redesigned park and riverfront. The Arch’s story at 50 (here).

The project to connect is also a project to disconnect the Mississippi River upland from flood damage. The Arch was closed when the river crested in June 2019 (here), but the GSN design allowed the river to be one. The wisdom of giving space revealed to thousands of visitors a clear vision of accommodation to a greater force. Turning all 2,200 miles of the Mississippi into a GSN River highway is not fanciful, given the eventual reality of no recovery and trillions in property damage.

Both the joys and threats of Nature in cities have led to a rational but fragmented green landscape. The country would benefit greatly from the implementation of an expanding green network. The question is, how? The creation of places such as this bit of St. Louis riverfront has developed with the idea that it could be of service to eighty percent of America’s people who live in urban areas. 

The Museum documents the important role rivers through St. Louis powered westward expansion over two centuries. Today visits to the “wilderness” have increased 100 fold since cars were allowed in national parks.  Since then, the purpose of expansion has begun to endanger the idea of “a wild,” and the national wilderness commons will become parks. Reducing the human footprint on them by as much as 90% is needed, as is a measuring device to prove the worth of it to all as a thing to remain untouched.

The hat and the Mississippi should tell the whole story.

GSN Certification

Measures for technical scrutiny of individual urban development projects reveal every aspect of human consumption. Those that reduce or eliminate ill effects can be identified with a value assigned but those that cause damage are difficult to define. There are many examples from parts per million of a GHG in the atmosphere, to the capacity of your local sewage treatment facility. We recognize the issue but remain unlikely to personally experience damage. A better example is more colloquial and by the people of St. Louis who have a personal understanding of river dynamics. It is the explanation of why living next to a river like the Mississippi is a poor choice. It is deciding to sleep next to a drunk elephant or a large disoriented snake.

Ease of communication with consumers has many resources regarding personal consumption, and environmental protection is steadily becoming an added layer. New data-sharing organizations such as the Good Guide and Footprint. The difficulty of this larger relationship with the environment is a basis for support. The Good Guide for example will “take a break” and close in June 2020. Efforts such as these build on understanding human behavior in a new way, but much in the same way the safety principles of the Underwriters Laboratory and utility value by Consumer Reports created a guardianship between product makers and users. The task of creating one between all human behavior and the earth that gave it life is a vastly different endeavor.

A GSN approach for measuring urban development practices will use certification. One of them is SEED, which stands for Social Economic Environmental Design. Another is LEED for Leadership in Energy and Environmental Design. As web-based design process tools, the SEED®Evaluator and LEED seek developers, their designers, and critics to respond to an independent third-party.  LEED’s development by the U.S. Green Building Council measures the environmental impacts of buildings. On the other hand, SEED counts the long term. For example, using the product of an unfragmented green space network, individual projects examined by LEED would be certified by SEED for their contribution to that goal.

Full certification acceptance of regional development practices and building rating systems suggested by SEED will be far more difficult. The United States (USGBC LEED) and Canada (CaGBC LEED) remain in the “good guide” phase of urban development. However, they function without the full containment demanded to examine social, economic, and long-term environmental consequences. Once proven, the next steps will require mandatory actions.


Another provocation or prompt in this dialogue series takes an idea from urbanization known as Urban Renewal and applies it to Open Space. Urban Renewal from the mid-1950s exposed failures in urban development by focusing on physical deterioration and its causes.

The “slum clearance” efforts following WWII (Housing Act of 1949 and 54) included people removal (largely low-income), social opposition, and eventually organized resistance to forced displacement. The acts established a major federal role directed at increasing the supply of affordable housing in cities. Almost simultaneously, federal policies sought to “spread the city” in the era of Atomic Bombs and nuclear proliferation. Sensitivity to change of any kind, including stress on social relations across cultures and color, has been the subject of hundreds of scholars, especially that of Alexander von Hoffman, Senior Fellow at the Joint Center for Housing Studies of Harvard University. There is much to be learned here in how the city might be rethought if there was a similar national policy interest. Finding ways and materials needed to sustain hopeful existence requires terminating continuous cycles of physical deterioration and the hideous waste of human lives.

Open Space Renewal can draw extensively on urban impacts. Ideas such as the Green Space Network require implementation strategies, and where better to look than efforts to re-imagine and model a vastly improved urban environment. The approach taken in this prompt speaks to the documentation of these efforts. It looks to the law and practice of controls that would be transferable to protecting the natural environment.


  1. For description, see VMT Energy Information Administration EIA (here) In Providence, Rhode Island, a federal and state highway project that plans to relocate Interstate 195 to produce about 20 acres in the downtown.  In the 1970s, the city altered the Woonasquatucket and Moshassuck Rivers course to achieve an urban design purpose. A study by Chan Krieger Sieniewicz, an urban design firm from Cambridge, MA, outlined this opportunity referencing Boston’s urban resilience in attacking challenging urban design problems to sustain a knowledge-based economy.
  2. The resources on the VMT define the problem, for example.
    1. Traffic Volume Trends. Federal Highway Administration. US Department of Transportation.
    2. Quick Start Guide, National Household Travel Survey, U.S. Department of Transportation.
    3. U.S. Highway Vehicle Miles Traveled. Bureau of Transportation Statistics. US Department of Transportation.
    4. White, Joseph B. The Next Car Debate: Total Miles Driven. The Wall Street Journal, February 5, 2008
    5. Vehicle Miles Traveled. Transportation Energy Consumption Surveys. Energy Information Administration, US Department of Energy. Chapter 3.
    6. Ewing, Reid. Growing Cooler: The Evidence on Urban Development and Climate Change.Chicago: Urban Land Institute, 2007.
    7. Lawrence Frank and Company, Inc. Reducing global warming and air pollution: the role of green development in California, prepared for Environmental Defense Fund. 2008.
    8. Frank, Lawrence, and J. Chapman. Integrating travel behavior and urban form data to address transportation and air quality problems in Atlanta. Prepared for the Georgia Department of Transportation Georgia Regional Transportation Authority. April 2004.
    9. Puentes, Robert, and A. Tomer. The Road Less Traveled: An Analysis of Vehicle Miles Traveled Trends in the U.S., Brookings Institute. 12.16/2008.
  3. A study by Chan Krieger Sieniewicz, an urban design firm from Cambridge, MA, outlined this opportunity referencing Boston’s urban resilience in attacking challenging urban design problems to sustain its knowledge-based economy.  See story: New York Times.
  4. See Urban Green Space Network: development for biodiversity conservation: Identification based on graph theory and gravity modeling
  5. The CA Map: “Wildland-urban interface maps vary with purpose and context” Stewart, Susan I.; Wilmer, Bo; Hammer, Roger B.; Aplet, Gregory H.; Hawbaker, Todd J.; Miller, Carol; Radeloff, Volker C., and the smaller map is that confirms major changes in the assessment of wildfire risk.
  6. See the Best Practices Manual: Wildlife Vehicle Collision Reduction Study Chapter 4 for an extensive review of design solutions.  Red Earth Overpass on the Trans-Canada Highway Banff National Park Alberta Canada (© A. P. Clevenger)
  7. See NYT  October 7, 2009 “The city will be taking legal action to assert our right to the Tavern on the Green trademark,” Connie Pankratz New York City Law Department. 
  8. Forest Park, home of the 1904 World’s Fair, stands as the second-largest urban park in America behind New York’s Central Park. And the Jefferson National Expansion Monument (better known to everyone as St. Louis Arch) is surrounded by park grounds taken back from the riverfront warehouse district.

The following formulas will be found in the Guide for Highway Capacity and Operations Analysis of Active Transportation and Demand Management Strategies (here). The provocation is to come up with one that saves lives and builds the GSN.

Equation 7. The number of days represented by the scenario is determined by multiplying its probability of occurrence by the total number of days in the reliability space being evaluated in this equation.
Vehicle Miles Traveled

Equation 7 Where:

AVMT = Annual total vehicle miles traveled
N = Number of days within the reliability analysis space.
VMT(s) = VMT estimate for scenario “s.”
P(s) = Probability of scenario “s.”

Equation 8. Equation for the annual vehicle-hours traveled (VHT) should include delays to vehicles waiting (or denied entry) to the facility during the study period, plus the time spent traveling or stopped within the facility.
Vehicle Hours Traveled

VHT’(s) = Adjusted vehicle-hours traveled for scenario “s” veh-hrs).
VHT(s) = Vehicle hours traveled reported by analysis tool for scenario “s” (veh-hrs).
DAP = Duration of analysis period, for HCM it is typically 15 minutes (min).
VDE(a) = Number of vehicles denied entry to facility at end of analysis period “a” (veh).
Q(j,s) = Number of vehicles remaining in queue on entry segments “j” at end of last analysis period for scenario “s” (veh).
c(j) = Capacity of facility entry segment “j” (veh/hr).

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