At present the county and city governments universally establish the fixed speed traps on the roads for clamping down on speeding and running a red light based on the reason of the traffic safety. It causes the populace to violate the traffic regulations incidentally and have the bad impression on the county and city governments who seem to enrich their local budget through setting traps. Essentially do speed trap devices have absolute relationship with the improvements in traffic condition and safety? It still needs verification and study. The governments raise the fine quite subjectively to curb speeding; however, now the domestic lacked research and discussion on the standard reliability of the speed traps. In addition, few people have the recognition of risks and terror appeal messages, such as fine or possible traffic accidents that might happen to the speeding populace. Therefore, we have to research into the aspects of changing the driving behaviors. The study range and the questionnaire design mainly define if the establishment of speed traps in fongsan city Kaohsiung County is a terror appeal to the drivers through risk communication and cognition. To survey the intention of obeying the laws and obtain the data, we implement the questionnaire survey on the common populace. It takes the risk communication and cognition as independent variable and the intention of obeying the laws as dependent variable. Through its deduction and the empirical study, it proves that the establishment and law enforcement of speed traps have the reinforcement and altruism on the law-abiding perception and the constraint to the populace. They will behave appropriately according to the information and the establishments; the governments will also make the most proper laws, regulations and the policies according to the data; finally this will help the individuals, the organizations or the society to make the choices tending to luck and avoiding disasters.