Abstract Driving style concerns the way a driver chooses to drive, and depends on physical and emotional conditions of the driver while driving. In order to validate this hypothesis, we propose a Structural Equation Modelling (SEM) aimed to investigate on the relationship among driving style and drivers’ characteristics such as somatic, behavioural and emotional conditions. Drivers’ conditions include tiredness, sleepiness, sickness, gloom, worry, nervousness, boredom, and anger. In the proposed model, driving style is considered as an endogenous latent construct, while drivers’ characteristics were considered as exogenous. Driving style is defined by means of a judgement expressed by the driver on a scale ranged from aggressive to cautious. In addition, a more reliable definition of the driving style is determined through an objective measure derived from cinematic parameters. We addressed to a sample of drivers a questionnaire aimed to collect information about their conditions while driving and the judgement about their driving style. Each driver registered the same path run in different days (more than thirty paths for each driver, in average), and complete the questionnaire for each path. This permits to observe the possible changes of drivers’ driving style as a function of the different physical and emotional states that drivers present in different days.