Urban emergency situations require accurate and timely decisions in order to reduce the impact of these incidents on human lives and civil property. Decision making in this time critical scenario is a challenging task because there are several variables influencing the process, and some of them change quickly. This process characteristic requires that decision makers monitor and adjust their decisions almost permanently until the situation is under control. Therefore, information availability and understandability become a key issue to improve the decision making process. This paper presents two decision support systems that implement a decision making model. The model helps determine which information must be used to support the decision making process, and also how frequently such information must be updated. The systems are intended to help allocate ambulances and fire trucks to urban emergencies.