Payesh
2010; 9: 21-28
Accepted: 7 July 2008
[EPub a head of print-17 August 2009]

Objective(s): To assess reliability and construct validity of the Manchester Driving Behavior Questionnaire (MDBQ).This questionnaire intends to determine abnormal driving behavior (errors and violations) that having psychological reasons and different modifying methods.
Methods: In first step, in order to verify construct validity, 293 drivers with second grade driving liscence were selected to complete questionnaire.In the second step, to assess reliability, 40 experienced drivers were selected and asked to answer questions.
Results: The results of factor analysis differentiated clearly four factors: slips, mistakes, intentional and unintentional violations. The results showed that all four factors have high internal consistency coefficients (slip: 0.77, mistakes: 0.81, intentional violation: 0.86, unintentional violation: 0.65).
Conclusion: This questionnaire is a valid and reliable instrument in assessing driving behavior.