The successful evacuation of vulnerable people during emergencies is a significant challenge. In the case of a Mount Merapi eruption, limited private vehicles in the community and a lack of evacuation transport and government volunteers led some people to walk to the meeting area. Consequently, low walking speeds by vulnerable persons may increase the risk and delay. Therefore, the mutual assistance strategy is proposed to support vulnerable people by evacuating them with young people. This grouping was simulated using an AnyLogic software with the agent-based model concept. Pedestrians and vehicles played the roles of significant agents in this experiment. Evacuation departure rate, actual walking speed, group size, route, and coordination were crucial agent parameters. Human behavior and agent distribution were investigated using stakeholders and local community interviews. We measured the walking speed directly to find the independent and group speed. Afterward, we developed three scenarios and models for the evacuation process. A traffic approach was used in the simulation. The results revealed that this mutual assistance model is effective for the rapid evacuation and risk reduction of vulnerable communities where successful evacuation rates have improved. The highest arrival rating was obtained by the Model 3, which was assembled and well-coordinated from home. These findings are a novelty in the volcano context and reflect all categories of vulnerable behavior involving the elderly, disabled, children, and pregnant mothers. The model will benefit disaster management studies and authorities’ policies for sustainable evacuation planning and aging population mitigation.