Risk level evaluation of transport of dangerous goods through road tunnels

The impact of vehicles transporting dangerous goods on the risk level in road tunnels is evaluated. Unidirectional tunnels with characteristics in compliance with the European Directive 2004/54/EC were in particular examined. Different percentages of dangerous goods vehicles (DGVs) considered as part of heavy good vehicles (HGVs) were investigated. The outcomes shown in terms of social risk, as F/N curves and as Expected Value (EV), prove that the risk level increases in a linear way with the percentage of DGVs. Furthermore, for a fixed value of DGVs, an increase in HGVs corresponds to a higher level of risk. Finally, longer tunnels present both higher gradients and major risk levels. These findings might assist Tunnel Management Agencies (TMAs) in making more appropriate decisions on possible limitations of the circulation of DGVs through tunnels.