In mountainous areas, tunnel portals and job sites for tunnel construction are often located in areas prone to rockfall events. Providing the safety of roads close to tunnel portals, subjected to rockfall risk, is an unavoidable issue that should be taken into account. In this paper, a risk management approach has been introduced to evaluate rockfall risk on the road stretch at the entrance and exit of tunnels. The event tree method
is improved to achieve a flexible solution to calculate the rockfall risk for tunnels. Furthermore, some design
abacuses are developed to provide the input parameters related to the event tree. Afterwards, a parametrical
analysis is presented to explain the methodology. The elaborated approach can be useful to choose best technical
solutions and design protection devices against rockfall
