A serious incident involving dangerous goods in a tunnel can be extremely costly in terms of loss of human lives, environmental degradation, tunnel damage and transport disruption. On the other hand, needlessly banning dangerous goods from tunnels may create unjustified economic costs. Moreover, such a ban might force operators to use more dangerous routes, such as densely populated areas, and thus increase the overall risk. This report proposes regulations and procedures to increase the safety and efficiency of transporting dangerous goods through road tunnels. It introduces two models, developed as part of the study: the first quantifies the risks involved in transporting dangerous goods through tunnels and by road; the second, a decision-support model, assists in the determination of the restrictions which need to be applied to the transport of dangerous goods through tunnels. Finally, measures to reduce both the risks and the consequences of incidents in tunnels are examined in detail.