There is a missing link, regarding infrastructure, from urban resilience reports, policies for zero carbon/decarbonization, and academic sustainable/resilient approaches. There is a clear focus on Supply infrastructure (natural resource and economics dominated, e.g. water source, reuse, fossil fuel vs renewables, and ROI) and Demand (social behavior consumption dominated, e.g. EVs, demand reduction, and efficiency). The missing link that connects these two foci is Distributive infrastructure - the existing pipes, cables, and wires that carry basic services from Supply to Demand. However, as Distributive infrastructure is buried out-of-sight-out-of-mind beneath the roads of our cities, this missing link is often not systematically addressed in infrastructure and urban resilience policy. Partly responsible for this oversight is a failure to communicate (CHL). Just referring to "infrastructure” is insufficient for any policy and requires clarification in order to address this missing link.
The World Bank’s Urban Sustainability Framework states:
“There are two types of investments that a city can make to improve sustainability: capacity building investments (soft infrastructure), and investments in physical assets (hard infrastructure).”
In other words, “infrastructure” can cover everything that a city invests in; from soft infrastructure that covers all social and essential services that a city may provide, to hard infrastructure that could include a municipal power station, to schools and sidewalks. By adding “aging urban” as descriptors to infrastructure, the focus is at least refined to the geographic boundaries of an urban area and the impacts of age to the hard assets  that are critical for maintaining reliable basic services. Yet, these descriptors still cover all sectors  of infrastructure, and does not embody the significant considerations for improving urban resilience. This blog focuses on better characterizing the Distributive infrastructure in our cities and the need to clean up the use of infrastructure descriptors.
Using additional descriptors, e.g. “critical”, rarely clarifies the range of aging urban infrastructure sectors. For example, an IoT project in New York State stated that the project:
“…will convert the City of Poughkeepsie's sidewalks and roads into an industrial IoT platform that streamlines the deployment and management of critical infrastructure, from power grids and broadband to sidewalks and water pipes.”
Granted, sidewalks are important to a city, but if they are “critical” infrastructure, then what is not? It seems best to adopt the definition of critical infrastructure per Presidential Policy Directive 21 (PPD-21) that the Department of Homeland Defense defined across 16 sectors (different than ASCE’s 16 categories used in the quadrennial Report Card) “…that are considered so vital that their incapacitation or destruction would have a debilitating effect on security, national economic security, national public health or safety, or any combination thereof.” Seems including sidewalks as critical would be a stretch to fit into this definition.
Similarly, using the “green” descriptor also creates confusion (discussed further in a previous blog). The term is often used to go beyond greenwashing to imply adaptive infrastructure resilience to the impacts of climate change and mitigative properties to reduce anthropogenic carbon emissions. Even though the EPA the National Green Infrastructure Certification Program definitions are limited to a single sector (stormwater) and do not mention climate resilience or carbon sequestration. Finally (for this blog), using the term “sustainable infrastructure” when discussing a specific sector (or single asset within a single sector, e.g. sustainable water plant), should not be misconstrued as contributing significantly to overall sustainable urban infrastructure, or resilience. The obvious reason is that one sustainable sector of infrastructure (or, a single asset within a single sector) cannot represent all sectors in a city. Rather, we should view all Distributive infrastructure as a single paradigm where all sectors are collocated in corrosive soil and covered with asphalt (our urban roads). This paradigm (RABID) is represented in cross section in Figure 1.
The reason why this paradigm of Distributive urban infrastructure is not addressed in resilience policy can generally fit under the Not-My-Job (NMJ) phenomenon. That is, whose job is it to think of the impacts of aging infrastructure in a city where the “built environment” has been dissected into multiple professional siloes (discussed further here). That is, urban planners focus on the overall built environment, but typically from a ground-level with a 2D perspective (a 3D perspective that includes underground urbanism was discussed here). Architects focus on vertical infrastructure (buildings). And, while engineers have the purview of horizontal infrastructure, the perspective is typically limited to one sector, or single asset, at a time. But, consider the immense impact to a city's viability/vitality, when the decaying process of age makes our urban infrastructure vulnerable and less reliable.
Consider an analogy that compares the cross section depicted in Figure 1 and the front of a car. Generally, a car is not purchased because of a shiny hood (i.e. a freshly paved road in this analogy), but because of the systems underneath the hood (buried infrastructure in this analogy). Any system that fails in a car, requires that the car stop and that the hood be opened to facilitate repairs. Similarly, our urban roads are constantly being cut in order to access the underlying infrastructure for repairs/replacement (covered in multiple blogs, but Toronto as an example). This is a major source of urban disruptions - that requires further quantification. What profession is looking at the connection between these daily disruptions and city viability/vitality? Contributing to the NMJ phenomenon is also the confusion of urban infrastructure ownership: 85 percent of the nation’s critical infrastructure is privately owned and the rest under the authority of overlapping jurisdictions (public, private, PPP, and special districts). However, regardless of NMJ (ownership or professional silo), it is the city that is impacted negatively by the disruptions caused by the legacy of aging infrastructure. The city must take ownership of these disruptions.
As all sectors move basic services (e.g. water, energy) from supply to consumption, there are inherent unique characteristics and expected functions along the way. That is, rather than just using the term “infrastructure”, we need to distinguish what transition is being addressed. Using another analogy to better illustrate transitions, this time a straw, where the straw represents the pipes and wires of our Distributive infrastructure that delivers basic services (e.g. energy, water, waste…etc.). On one end of the straw is Supply (dominated by natural resource and utility business ROI considerations) where we pour in processed natural resources (e.g. raw water to potable). The straw then distributes the basic services to end-user Demand (dominated by social behavioral expectations) at the other end of the straw for consumption. The straw has no other role other than a conveying function that should be reliable (baseline conditions) and resilient (rebound/fall forward after shocks). However, the assumption that the Distributive infrastructure is reliable and resilient is constantly proved false. The daily need to access the straw (Distributive infrastructure) for maintenance/repair acts to disrupt city-life (550 times PER DAY in NYC). It is this disruption, more than the embodied energy of the materials of the straw that dominates the characteristics of this transition. And, currently, there is not a methodology in place to quantify this disruption and impacts to urban resilience.
Generally, sustainability outcomes occur at either end of the straw based on the choices of stakeholders: Supply transition (environmental degradation; renewables vs fossil fuels; or water reuse vs another dam) and the End-user transition (social behavioral characteristics; i.e. how much is each customer consuming; distributed with equity, quality, and accessibility). Does the copper wire (i.e. the 'straw') care if the electrons that it conveys are renewable or fossil-fuel based? This simple analogy can be expanded into multiple levels of complexity, as shown on Figure 2 (more detail here). Point being, a city’s Distributive infrastructure is a different transition than the Supply, Demand, Transmission, …etc. transitions. And, is placed in a different paradigm with different expected outcomes.
Again, the word “infrastructure” could apply to almost anything. And, the use of descriptors rarely refines the scope of policy/planning. Effective infrastructure policy requires defining the characteristic hazards, vulnerabilities, and expected outcomes associated with specific transitions and paradigms. Because there is not a systematic methodology for addressing a city’s aging distributive transition, the associated chronic hazards are therefore not addressed in urban resilience reports. Defining transitions also applies to more regional/national decarbonization policies as well. Using the America’s Zero Carbon Action Plan an example, consider that “…the transition from a high-carbon to a low-carbon energy system is based on three pillars: (1) using energy more efficiently, (2) decarbonizing electricity, and (3) switching from fuel combustion in end uses to electricity.” No arguments. But if these “3 pillars” were further defined by transition, then pillars #1 and #3 would fall under the social behavioral characteristics of the Demand (consumption) transition. And, Pillar #2 would fall under the Supply transition and the characteristics would include natural resource choice, business plan of the utility (price per unit delivered), and climate resilience of the assets. The report also states that:
“U.S. cities have significant power to address climate action due to their ownership of key assets,…”
While true, it is important for decision-makers to understand that infrastructure capex investments intended to achieve an improved climate action, will not also address the disruptions caused by aging infrastructure in their cities until we improve our communication.
 ‘asset’ is defined as a component of an infrastructure sector (e.g. energy) or subsector (e.g. gas main)
 ‘sector’ refers to the individual infrastructure systems that delivers an essential service to the city, for example, transportation, energy, water, sewer, solid waste, stormwater, etc. through pipes, cables, vehicles, pavement, etc.