Source: adapted from OECD (2009) “Applications of Complexity Science for Public Policy: New Tools for Finding Unanticipated Consequences and Unrealized Opportunities”, Global Science Forum.
Transportation, as a complex system, shares many of its characteristics, including:
- Adaptability. A standard characteristic best reflected by the concept of competition, where transport firms adapt to their competitors and other socioeconomic changes (demand). Investment in new and expanded infrastructure is also an adaptation strategy followed by corporations and governments.
- Self-organization. Routing within a transport network represents the characteristic of self-organization, as the intermodal sequence is the outcome of considering the respective advantages of modes and terminals. Supply chain management is also illustrative of self-organization as sourcing and distribution strategies change to reflect complex input and distribution costs.
- Stability. This represents the stable components of the transport system that have a long-term influence on the nature and extent of flows. Land use is a particularly stable component of spatial interactions since its characteristics are slow to change. The same applies to transport terminals, which are long-term locations where flows converge.
- Cumulative. Congestion is a good example of a non-linear characteristic of transportation, as each degree of additional congestion results in exponential delays. Various disruptions over transport networks are also an instance of non-linearity, as a relatively simple event such as the shutting down of an airport hub (e.g., a snowstorm) will trigger disproportionate disruptions through the whole network.
- Phase transition. Several events may trigger substantial changes in transport systems. One type relates to technological (or technical) innovations that historically have been paradigm shifts for the transportation system. For instance, containerization is linked to new flow patterns, modes, and terminals; it created a new transport system. Automation continues to impact transportation systems through vehicles and processes. Issues related to carbon emissions are also considered to be a highly susceptible factor triggering a phase transition for 21st-century transport systems.