The objective of this research was to study thebehavior and factors effecting traffic violator byprivate car drivers as well as to study and analysedthe way to improve the behavior of private car driversand decrease the traffic problems in BangkokMetropolis. The study focused on the governmentofficers in the Office of Permanant Secretaty forInterior by using 1. 280 questionnaire forms 2. interviewed 10 cars drivers, 6 traffic policeofficers and 3. observed 3 congested intersections(Baromratchonnanee, BangPlat, Siriraj). The result of this study showed that the averageindex of traffic violator of government officers in theOffice of Permanant Secretary for Interior was 1.137and the finding were as follow: 1. Those who had low educational level (lowerthan bachelor degree) violated the traffic laws lessthan those who had higher educational level. 2. The position level did not have any effect ontraffic violation. 3. The one who had more experienced in drivingviolated the traffic laws more than those who had lessexperienced in driving. 4. The one who had less knowledge in traffic lawsviolated the traffic laws more than those who had moreknowledge in traffic laws. 5. The one who showing pessimism in followingtraffic laws violated traffic laws more than those whoshowing optimism in following traffic laws.