The eruption of Mount Merapi in 2010 killed more than 400 people. An optimal evacuation is strongly affected by road network preparedness used as an evacuation route. This study aims at developing an evacuation model from the disaster to identify road network vulnerability in optimizing evacuation route performance. The evacuation modeling employed a useroptimal method to analyze changes in road network performance in the form of flow as a basis for developing a formula to measure road network vulnerability. The results indicated increased flows on the road network areas of ring 1, ring 2, ring 3, and Sleman outside the ring. By employing the developed vulnerability equation, the road networks identified vulnerability of ring 1, ring 2, ring 3, and Sleman outside the ring indicated by positive index values. Meanwhile, the road networks in Yogyakarta City, Bantul, Kulon Progo, and Gunung Kidul were identified as invulnerable indicated by the negative index values.
