International audienceThis paper is an abstract of my PhD. thesis in Geography (Demoraes F., 2004). The objective of this research was to suggest a reflection on the risks the Metropolitan District of Quito is exposed to, considering more specifically road network vulnerability and accessibility issues. The analysis was conducted within the framework of a research programme called “Information System and Risks in the Metropolitan District of Quito” carried out between 1999 and 2004 by the French Development Research Institute (IRD) in partnership with the Municipality of Quito. We argued that in order to prevent efficiently the risks a city is exposed to, it is indispensable to first pinpoint the critical infrastructures and lifelines on wh...