Injuries constitute one of the priority health problems in the world that lead to the loss of several million lives and cause nonfatal injuries to millions of people globally.The objective of the study was to determine the precrash factors associated with the nature and outcomes of injuries in traffic accidents in Makueni County. This would provide evidence for the development of policies and programmes in emergency medical services. The Mixed method approach and cross-sectional study design was employed. Data was collected from 427 First Responders and 474 patients. Universal sampling was employed for all the consecutive First Responders who assisted people inflicted with Injuries conveyed to six hospitals in Makueni. Quantitative data analysis was through Statistical Package for Social Scientists version 25 while qualitative data was through descriptive and analytical reports. Study findings indicate a significant relationship between Outcomes of injuries with use of personal protective device, education level of casualties, location of health facility, time the accident occurred andthe weather during the accident. The study recommends regular community members’ sensitization and training on pre-hospital emergency care for road traffic related casualties. Sensitization should prioritize issues such as use of personal protective equipment to reduce morbidity and mortality with emphasis to the most affected such as the males.