Quantifying the Impacts of Transportation-Communication Interdependencies on the Resilience of Diverse Populations

Resilience of a community to disruptions in a public transportation system depends not only on the technical systems’ ability to maintain service levels, but also on the ability of individuals to cope with and adapt to disruptions. In adapting to travel disruptions, individuals rely on information. Well-informed decisions depend on effective communication with vehicle operators, transit websites, other customers, or social media. Furthermore, the ability to make contingency plans depends on communication with childcare providers, family members, and work supervisors. Thus, a community’s resilience to transit disruptions must be considered in the context of a paired public transportation-communication system. When delays or interruptions in service occur, consequences are different for different users. Different populations have different levels of job flexibility, Low-skilled workers, for example, may only be paid for work performed at the job location. If they are late, they will not only risk wages, but may lose their jobs. If transit disruptions are planned, people with higher incomes may drive or take a taxi to work or simply work from home. Family and friend support systems may enable greater flexibility in departure time for some riders, where for example, childcare is required. Furthermore, the consequences of transit disruptions are less severe for users who are able to make substitutions. This ability may depend on access to (1) physical resources (e.g car, bike, money for a taxi, smart phone), (2) knowledge (e.g. familiarity with bus system), and (3) community resources (e.g. rides from neighbors, carpooling). It may be reasonable to quantify the resilience of the paired transportationcommunication system as a technical system, thus considering its ability for continued operations under disruption. However, understanding how resilient a community is to a disruption in this paired system requires a representation that reflects not only the system’s engineered components and connections, but also incorporates user capability and sociosystem interactions. Some actions taken by the users may exacerbate the shortcomings of the technical system, while other actions may help. Cyclic interdependencies between engineered components and socio-system actions may result. For example, improvements to a transit website may increase its number of users. However, as demand increases, so does the likelihood that the server will go down thus rendering the website useless. Such interactions create the need for an integrated socio technical framework, wherein people act as part of the system, not just as its end users or decision-makers.