This lecture, part of the "Crisis and Disaster Management Training (a)" course, provides an in-depth exploration of ventilation systems in road tunnels with a focus on their critical role in maintaining safety and air quality. Topics include the principles and applications of natural and mechanical ventilation systems, their advantages and recent technological advancements. Special attention is given to managing ventilation during emergencies, such as tunnel fires, with strategies to safeguard users and enhance disaster response efficiency.