Association of risky driving behavior with psychiatric disorders among Iranian drivers:A case-control study

Purpose:This study aimed to investigate the possible association between psychological disorders and riskydriving behavior(RDB)in Iran.Methods:This case-control study conducted in Shiraz,Iran in 2021.The case group included drivers with psychological disorders and the control group included those without any disorders.The inclusion criteria for selecting patients were:active driving at the time of the study,being 18-65 years old,having a driving license,having a psychological disorder including depression,bipolar disorder,anxiety spectrum disorder,or psychotic disorder spectrum confirmed by a psychiatrist,and completing an informed consent form.The exclusion criterion was the existence of conditions that interfered with answering and understanding the questions.The inclusion criteria for selecting the healthy cases were:active driving at the time of the study,being 18-65 years old,having a driving license,lack of any past or present history of psychiatric problems,and completing an informed consent form.The data were gathered using a researcher-made checklist and Manchester driving behavior questionnaire.First,partition around medoids method was used to extract clusters of RDB.Then,backward logistic regression was applied to investigate the association between the independent variables and the clusters of RDB.Results:The sample comprised of 344(153 with psychological disorder and 191 without confirmed psychological disorder)drivers.Backward elimination logistic regression on total data revealed that share of medical expenditure≤10%of total household expenditure(OR=3.27,95%Cl:1.48-7.24),psychological disorder(OR=3.08,95%Cl:1.67-5.70),and substance abuse class(OR=6.38,95%CI:3.55-11.48)wereassociatedwithhighlevelof RDB.Conclusion:Substance abuse,psychological illnesses,and share of medical costs from total household expenditure were found to be main predictors of RDB.Further investigations are necessary to explain the impact of different psychological illnesses on driving behavior.

Evaluation of red-light camera enforcement using traffic violations

The State of O.atar started to use red-light cameras in 2007 at key signalized intersections and the rate of installation has subsequently increased. In 2017, 19.2% of signalized intersections are equipped with red-light cameras. In many cases, the cameras are not installed on all approaches to the intersections. The purpose of this study is to compare the red-light running violations on approaches with and without red-light running enforcement cameras at the same intersections. Actual field observations were used in this study. Different vari- ables were investigated, including the day of the week, time of day, traffic volume, the possibility of glare on an approach, and the lengths of the yellow and all-red times. A regression tree model was used to explain the characteristics associated with the violations. The results showed that the number of violations on low-volume approaches was five times higher than on high-volume approaches. The results also showed that the presence of the cameras significantly lowered red-light running violations. High-volume approaches without cameras had an approximately eight times higher rate of violations than high-vol- ume approaches with cameras. The analysis also showed that bringing the all-red interval closer to the values recommended by the Institute of Transportation Engineers formula may bring down the rates of violations for low-volume approaches. As with any observational data mining method, the study could benefit from a larger sample size. The method used in the study was effective and is easily transferable to other locations. The results of this study can be used in developing new strategies to improve safety at signalized intersections.