## 5 Conclusions  
We explored the vulnerable accessibility to emergency medical services (EMS) by region and time considering the speed limit and real speed of roads. The main findings showed that urban and rural areas have different characteristics in terms of access to an emergency medical facility. In urban areas, the congested road traffic flow (particularly during rush hour) delays the access time. In contrast, in rural areas, the far physical distance to an emergency medical facility increases the travel time, because most emergency medical facilities are concentrated in urban areas. We also found that assessing vulnerable areas to EMS based on the speed limit of roads, as in the existing standard, underestimates the time to a medical facility because it does not reflect the real road conditions.  
This study delivers significant meaning to the existing government's approach to define vulnerable areas for emergency care and shows the potential possibility of the underestimation to reflect real world through big data analysis using activity data (real-time road speed) and geographical data (spatial information). However, the study results can be improved with more data sources for the following: First, we assume that there is no delay time due to traffic signals as well as no extra time to prepare the EMT-P's dispatch in 119-safety center which would ultimately have affected the survival rate of emergency patients. Second, we supposed that all emergency patients will be transferred to the nearest emergency medical center although patients can be transferred to different emergency centers following the patient's choices or medical conditions of the center such as medical manpower and equipment. Third, the influence of epidemic conditions such as COVID-19 cannot be considered even though pandemic diseases potentially restrict the accessibility of emergency patients because of uncertain information and related laws to prevent the possibility of infection for medical personnel and other patients in the medical facilities.  
We expect that future studies overcome current data availability issues for modeling precise cases including EMT-P's actual dispatch time and arrival time as well as the exact transferred emergency center location of emergency patients. Our ongoing studies will not only provide more accurate assessment of vulnerable areas for EMS but also suggest optimal transport systems for regional emergency medical services.  
Conceptualization, J.J., S.K., and K.S.; methodology, J.J.; software, J.J.; validation, G.H.K. and K.S.; formal analysis, J.J.; investigation, S.K. and K.S.; resources, J.J. and G.H.K.; data curation, J.J., G.H.K. and K.S.; writing--original draft preparation, J.J. and S.K.; writing--review and editing, J.J., S.K. and K.S.; visualization, J.J. and S.K.; supervision, K.S.; project administration, K.S.; funding acquisition, K.S. All authors have read and agreed to the published version of the manuscript. This research was supported by Basic Science Research Program through the National Research Foundation of Korea(NRF) funded by the Ministry of Education(NRF-2020R1A6A3A13075970). The authors declare no conflict of interest.