The importance of using seat belt is now obvious and has been proved in various studies , of course it is worth mentioning that using seat belt can decrease the severity of the accidents and injuries caused by them, but has no effect in preventing the occurrence of the accidents.1,5,9,13,16-17 A study conducted in year 2006 indicated that two third of the death injuries in car accidents were related to passengers and drivers not fastening seat belts.18 The time of the accident is considered as another important factor to be studied, it is expected that due to the decrease of eye sight during the late mid-night the number of accidents increases, but our results re- jected this assumption. In other studies, it was shown that 72% of the accidents occurred from 6 am to 18 pm, of course some results from the traffic police in- dicated that most accidents occurred during 5 to 8 am and 16 to 20 pm.4,7,13 Of course, these results can not be generalized since they have been descriptive and did not investi- gate the effect of the time of the accidents on the se- verity of the accidents. The present study shows the correlation of the time of the accident with the severi- ty of the accidents and as it is indicated in the results, the severity of the accidents during 12-18 pm has been less than 6-12 am, the accidents occurring dur- ing 18-24 pm as well have been more severe in com- parison to the accidents taking place during 6-12 am. We have indicated in this study that 20.9% of the case group experienced combustion during the acci- dent, but this number is reported to be 1.3% in the control group. The influence of this factor on the oth- er hand is important on the injuries to the drivers and References 1 2 3 4 Peden M. World report on road traffic injury prevention. World Health Organization Geneva; 2004. Peden M, Scurfield R, Sleet D, Mo- han DHAA, Jarawan E. World report on road traffic injury prevention. Ge- neva: World Health Organization; 2004. 2006. Naghavi M, Akbari M-E. Epidemiol- ogy of injuries resulting from extrin- sic causes (accidents) in islamic re- public of iran [Persian]. Fekrat Cul- tural Publishing Institute. 2002. Mehr-Boradcasting-AgencyTehran. The ominous shadow of death on insecure roads of the country [Far- si]. Electronic magazine of Iran Em- rooz; 2004 [updated 2004 [cited 2008 10/11/2008]]; Available from: WWW.ircmj.com Vol 13 August 2011 Relative risk on car accidents passengers which are both due to the severe contact and the fire. In khalaji et al.’s study, this number is reported smaller than the present study i.e. 6.3% in the case group and 0% in the control group.5 The modernity or model factor of the cars during accident was also studied in both researches, although no significant difference was observed in both groups but generally the number of modern cars was higher in the case group which may relate to the higher speed of these cars or the relaxation effect caused by the comfort of the more modern cars which can make the driver less cautious while driving on the road and consequently cause accident. We can conclude that using seat belt can decrease the severity of the injuries caused by the accidents or prevent the injury of the driver. The low age of the driver may also be considered as a risk factor which can cause accidents on the roads and can be mini- mized by means of media awareness and training. Acknowledgment Our special thanks and appreciations go to the re- spected Deputy of Research, Mashhad University of Medical Sciences, who assisted us in performing this project; we also thank the thoughtful traffic police of Khorasan-Razavi province who helped us in collect- ing related data. This study was supported by Mash- had University of Medical Sciences. Conflict of interest: None declared. 5 6 7 8 www.iran-emrooz.net/index.php?/ news1/print/6184/. Khalaji K, S. M, Eshraghian M, Mo- tavalian A, Halakouei-Naeini K. Risk Factors for Road Trafﬁc Injuries on Qazvin- Loshan Road-2005. Iran J Epidemiol 2006;12:27-35. Almasi A, Hashemian A. Frequency distribution of street vehicle acci- dents in Kermanshah (1998). BEH- BOOD; 2002. Famil M, Ghazizadeh A. An epide- miological survey of lead to death road accidents in Tehran province in 1999. Sci J Kurdistan Univ Med Sci 2002;6:35-40. Famil M, Sadri O. An epidemiological survey of road accident led to death in hamedan area, Iran, 1999-2000. Sci J Forensic Med 2000;6:5-12. 9 Rangraz JF, Farzandipour M. Epi- demiology of trauma in patients hospitalized in Naghavi Hospital, Kashan, 2000. FEYZ. 2002. 10 Saki M, Ehsan Saleh A, Moshfeghi GF. Epidemiological study of road accidents resulting in death, lorestan province, 199- 200112. Sci J Forensic Med 2003;8:24-8. 11 Salari A-A, Aghili A, Piraye-Haddad F. Demography of trauma patients due to driving accident in Yazd city. Shahid Sadoughi Univ Med Sci J 2002;3:19-26. [Farsi] 12 Vafaee A, Seyednozadi M, Jazani R, Shakeri M. Epidemiologic study of motor vehicle accidents resulting in injury and death in Mashhad, Iran 535