“…Specifically, this approach is to summarize the observed data into the values of several variables, and then it uses expert judgment based on the experience (Ahn, Rhee, & You, 2012;Lopez-Santander & Lawry, 2016) and navigation rules Lopez-Santander & Lawry, 2016) to combine these value into a single assessment of the collision risk. The collision alarm is then triggered by comparison of the risk level with a certain threshold that also relies on expert judgments (Baldauf, Benedict, Fischer, Motz, & Schröder-Hinrichs, 2011;Hilgert & Baldauf, 1997). In a word, the measured collision risk represents the degree of experts' belief on the occurrence of the collisions.…”