The human-machine interface (HMI) of a warning system should not be the cause of unintended consequences, such as startling or confusing the driver. The driver should be able to quickly understand and assess a threat and appropriately respond to the external event. In most instances, warning signals are used to inform the driver of a situation that he/she does not perceive on his/her own. If the driver is not aware of the situation, then the warning signal should be comprehended and clearly distinguished from other warning signals.Timely Comprehension is a laboratory methodology developed with the goal of evaluating integrated warning systems in development. Currently, no standardized verification method publically exists to evaluate the in-vehicle integration of warning systems. This methodology can help identify comprehension/distinguish-ability issues prior to full system development in a controlled, repeatable and safe setting. Timely Comprehension is based on the premise that each warning signals presented in the vehicle should be comprehended and distinguished from others in an integrated context. The foundation for the methodology lies with previous vehicle research on icon comprehension testing and perception-response time.While validation studies of the Timely Comprehension methodology remain to be conducted, this procedure is built upon the foundation of much previous research and justifies further exploration and refinement.