The terrorist threat has moved away from the national arena to a form of international terrorism designed to destabilise whole societies and their public opinion rather than make a particular claim. The means deployed can be highly sophisticated and are often the work of terrorists who have no hesitation in sacrificing their own lives for the cause.
Here, the public transport system, which has only been an occasional target in the past, appears to have become a preferred objective by reason of its vulnerability, a characteristic imposed by its size and the number of people it carries. Public transport systems are open and accessible to all, generally without individual access controls or passenger identification. Terrorist attacks generate extensive media coverage at a global level, which not only affects the image of public transport but also discredits the country and its government and the social organisations.