Many recent investigations and report revealed that mobile phone use while driving may seriously influence the traffic safety. Therefore a study to examine and investigate driving behavior during the use of mobile phone is necessary. In this study, four methods were used to collect possible driving influence data. They are: driving reaction test using simulator, accident records, mail survey to accident related personnel and general public opinion survey. Through statisical analysis, it is found that phone calling during driving is one of major factors to influence driving safety. And it is suggested that further action be taken to protect public and individual safety.