The waiting time can be reduced by providing information on bus arrival time. The absence of this information leads to long waiting time and affects passengers' planning travel time. Although the waiting period that is longer or shorter is subjective to each passenger, without information on bus arrival times, the uncertain passenger arrival time may cause difficulties to determine realistic waiting time. This study concentrates on the optimal design of the waiting time from the passengers' arrival time at random. The survey data were observed from one bus stop encoded as ALMD stop in Putrajaya. This stop has no mechanism for real bus arrival information, which raises issue of inconsistent bus arrival times to bus passengers. To analyze the problems, the combination of mathematics and response surface methodology-central composite design applications is used to design optimum waiting time. The design of arrival time was set up into two interval minutes: between 0-29 and 30-59 minutes, which was considered as the random arrival time of passengers. The modification on intervals for waiting time was designed between 0 and 15 minutes to meet the criteria of headway, one bus within 30 minutes. The design outputs resulted in a mathematical model for waiting time and optimization value. The results generated an optimum waiting time of 8.7 minutes for the first passenger and 13.81 minutes for the next passenger, which were the best times with respect to the bus operation headway.