The Dynamic Nature of Risk Perceptions After a Fatal Transit Accident

Abstract

In 2009, two trains of Washington, DC's Metrorail system collided, resulting in nine deaths and 50 serious injuries. Based on a multiwave survey of Metrorail users in the months after the crash, this article reports how the accident appears to have (1) changed over time the tradeoffs among safety, speed, frequency of service, cost, and reliability that the transit users stated they were willing to make in the postaccident period and (2) altered transit users' concerns about safety as a function of time and distance from the accident site. We employ conditional logit models to examine tradeoffs among stated preferences for system performance measures after the accident, as well as the influence that respondent characteristics of transit use, location, income, age, and gender have on these preference tradeoffs. As expected, respondents appear averse to longer headways between trains, longer travel durations, higher travel costs, a higher number of late trains, and a higher number of fatalities. The models also show evidence of higher aversion to fatalities from transit system operation among females compared to males. In addition, respondents less experienced with Metrorail travel and those with lower household incomes show higher aversion to fatalities, and this aversion increases as a subject's psychological distance from the accident site decreases. Contrary to expectations shaped by previous studies, aversion to fatalities appears to have increased between the early months after the accident and the end of the survey period, and the expected relationship between age and aversion to fatalities is not statistically significant.

Real‐Time Warning and Risk Assessment of Tailings Dam Disaster Status Based on Dynamic Hierarchy‐Grey Relation Analysis

“…A correlation assessment matrix is constructed based on the critical early warning points for each element in Table 3 in combination with the selected optimal evaluation reference data. Taking the six "inherent risks" categories as an example, the matrix obtained after dimensionless processing is as follows: The difference between rows and rows are calculated according to (10), and the matrix is reobtained as follows: From the above, = 0.421, = 0; therefore, the available correlation coefficient 5×6 and the correlation degree can be calculated using (12) and 13…”

“…The GRA method can use mathematics to effectively solve the lack of theoretical uncertainty information. GRA method uses less data modelling than the first six methods and has a goal of establishing differential equations, characterized by dynamic time series used for prediction and decision-making [10]. Applying the GRA method combined with the AHP can effectively overcome the problem of high correlation ambiguity.…”

“…Risk decision-making is uncertain because risks are themselves uncertain and dynamic [9,10]. The analytic hierarchy process (AHP) is a widely used quantitative and qualitative analysis method suitable for situations in which the results of decisions are difficult to measure directly and accurately (Table 1) [11][12][13][14].…”

Assessing U.S. Travelers Trade-offs for Aviation Safety Objectives: A Natural Experiment

“…The reduction in ridership persisted for months, and there was evidence showing that the reduction may have continued for almost a year. In a recent study on risk perception after the collision between two Washington DC's Metrorail trains, Wernstedt and Murray-Tuite [12] found evidence contradicting the time decay hypothesis. In particular, they found a positive and statistically significant relationship between the passage of time and safety concerns.…”

“…Nevertheless, evidence against the time decay hypothesis has also been reported in other studies. For example, Wernstedt and Murray-Tuite [12] used survey data to model trade-offs for safety after the collision of two DC Metrorail's trains. Researchers found a significant and positive relationship between trade-offs for safety and time, which suggests that passengers valued safety more as the event faded.…”