Urban road network vulnerability: assessment considering risk and greenhouse gas emissions

A network is vulnerable when the inefficiency of one or more links exerts negative externalities that may compromise the accessibility. The literature presents procedures that can be used in the network vulnerability assessment, which are divided into two groups: complete calculation and pre-defined criteria. The first ones, scan the network in order to find the most vulnerable links, on the other hand procedures that consider predefined criteria use indirect approaches to obtain the vulnerability. This paper presents a framework to road network vulnerability analysis based on the risk and environmental aspects. Hence, we developed a new procedure to verify the effectiveness of risk as an attribute to find the most vulnerable links of a road network, considering distance and CO2-eq emissions. Results showed an increase up to 8.51% (total distance traveled) when links with high risk are disrupted. CO2-eq emissions yielded the same outcome, disruptions of high risk links caused an increase up to 9.19%, whereas the safest links caused an average increase of only 5.54% when disrupted. Therefore, the number of scenarios modeled (for collecting data) as well as the Monte Carlo simulation were effective in assessing the impacts over time.