The Quantitative Assessment of Debris Flow Risk to Road Users on the Scottish Trunk Road Network

This report presents the methodology developed for undertaking a quantitative risk assessment (QRA) for the impact of debris flow on roads. It also presents a first use of  the methodology at the A83 Rest and be Thankful in Scotland. The methodology  considers the probability of an event of a typical size, and the conditional probabilities of a vehicle being affected, given an event, and of damage (fatality) occurring given that the vehicle is affected.