The External Validity of Psychometric Testing Methods and Their Meaning for Safe Road Performance

The aim of the paper is to investigate which psychometric tools commonly used by Polish transport psychologists appropriately measure necessary abilities of professional drivers. According to Levis-Evans' differentiation between the driver's performance and the driver's behavior, we explored a statistical relation between the results of tests currently used by transport psychologists, measured according to Szalma's individual differences and safe behaviors on roads. We examine validity of tests using data based on real professional drivers' behavior. The sample included 200 drivers involved in accidents and collisions, and 100 who behaved safely. We tested external validity of chosen psychometric tools by analyzing statistically the relation between test scores and unsafe driving behavior recorded by the police. The results show that only few measurements are valid for differentiation of safe and unsafe drivers. The paper indicates the methodology to reach the prognostic value of the diagnostic tests employed by transport psychologist.