The analysis of events related to the transport of radioactive materials shows that most of them are not only due to technical issues, but also involve human and organizational factors as a root cause. Indeed, human and organizational factors, such as competences, work environment, task characteristics and organization, have an effect on the safety of transport activities. In this regard, the analysis of the transport related events performed by the French Institute for Radioprotection and Nuclear Safety (IRSN) takes into account these factors in order to identify the causes of the most significant events occurred in France and to assess the actions put in place by consignors and carriers in order to prevent their recurrence. These analyses can focus on the organization implemented for the transport activities, including the operators training program and the means to take into account the operational feedback. In addition, on-site visits and interviews with operators and managers enable a better understanding of the organization (interfaces, roles and responsibilities), the working conditions and the possible difficulties related to the applicable procedures. In 2018, such an assessment has been performed by IRSN after the declaration of an event involving the loading operations of packages designed to transport spent fuel. The paper will describe the methodology applied for this analysis and present the main conclusions drawn from this assessment. The paper will also describe the major human and organizational factors that need to be taken into account in the safety of transport of radioactive materials. In fact, IRSN considers that the design process of packages and associated tools must include human factors engineering (co-design and validation with users addressing the future operating conditions). Furthermore, the safety functions ensured by the safety related components should be explained to the package users to improve their understanding of the different operations that should be performed at each step of the package transport, including loading and unloading.