Considering the significant influence of the human factor on safe driving behavior, the i-DREAMS project developed a ‘Safety Tolerance Zone (STZ)’ to define the precise boundary where self-regulated control can be maintained safely. Taking to account the framework of the i-DREAMS project, this paper endeavors to model the inter-relationship among task complexity, coping capacity (i.e. vehicle and operator state) and crash risk. A complete Structural Equation Model (SEM) was developed for each country of analysis (i.e., Belgium, United Kingdom, Germany) to describe the interactions between task complexity and coping capacity (i.e., related to both vehicle state and operator state factors). Results showed positive correlation of task complexity and coping capacity that implies that driver’s coping capacity increased as the complexity of driving task increases.