This research is to get a better understanding of what kind of intention is needed to communicate between drives and autonomous car. What types of communication methods should be used to offer a better user experience to drivers and passengers. In this study, we examined the effects of information type (“why” message, “how” message) and speaker gender (female voice, male voice) voice messages that provide communication about the car operations in advance before the autonomous car’s action. 30 participants took part in this experiment. Results showed that female voice was more trustworthy, acceptable and pleasure than the male voice, because participants were more familiar with female voice as it was widely used in smart device and navigation system. Also, the female voice is easier to hear than the male voice in the noisy condition. More than half of the participants changed their preference for the speaker gender, which reminds researchers to be cautious about the results of an online survey of drivers’ attitude to speaker gender. How message is preferred by participants. It is considered to be more intelligent and interesting than why message as it described what automated activity it is undertaking directly, participants didn’t need to take part in the decision process which may add their cognitive load. Additionally, how message uses the first person word like “I” “we” or “us” to communicate with the drivers increase participants’ trust and satisfaction.