Humanitarian aid workers belonging to United Nations organisations, PVOs / NGOs or the Red Cross / Red Crescent have traditionally enjoyed both international legal protection, and de facto immunity from attack by belligerent parties. However, attacks on humanitarian workers have occasionally occurred, and became more frequent since the 1990s and 2000s. In 2012 there were 167 incidents of major violence against aid workers and in 2013 there were 474 attacks. This is attributed to a number of factors, including the increasing number of humanitarian workers deployed, the increasingly unstable environments in which they work, and the erosion of the perception of neutrality and independence. In 2012, road travel was seen to be most dangerous and kidnappings of aid workers have quadrupled in the