Validity and Reliability of the Persian Version of the Dula Dangerous Driving Index

Road traffic accidents (RTAs) have always a major concern and human factor has been recognized as their leading cause. Since taxi drivers play a significant role in accidents, the main purpose of this study was to provide a valid and reliable version of the Dula Dangerous Driving Index (3DI) for taxi drivers working in the city of Zanjan, Iran.

Based on the convenience sampling method, 316 taxi (including taxi, internet taxi, etc.) drivers were recruited in this descriptive study. The 3DI contained 28 items within three factors related to dangerous driving behavior. After linguistic validation, qualitative and quantitative face validity was determined for the given questionnaire. Consequently, content validity index (CVI) and content validity ratio (CVR) were assessed by a panel of 10 experts. Internal reliability was further calculated based on Cronbach’s alpha coefficient and test-retest method.

The results revealed that face validity (1.60-3.82.), CVR (0.8-1), and CVI (0.891-1) were acceptable. Cronbach’s alpha coefficient was also 0.896 for the total reliability of the instrument and 0.95, 0.89, and 0.94 for each factor, respectively. In addition, Spearman’s rank correlation coefficient was 0.871 (P-value<0.001).

The results ultimately demonstrated that the Persian version of the 3DI had adequate reliability, as well as, face and content validity. However, construct validity remains.