Abstract
This study builds on previous research examining the concept of travel decision flexibility based on theories related to adaptive decision making, which argue that travelers perceive different levels of flexibility depending on the trip-related decision. The results of this study indicate that there are two distinctive types of decision flexibility, which are related to the timing and components of the trip: pretrip and en route flexibility. The constructs are examined for their external validity using several travel situational factors, including number of alternatives, prior knowledge, length of stay, planning horizon, and types of travel groups. These findings are important in that they help us to understand better the underlying structure and characteristics of travel decisions and, in turn, help us identify potential ways to design more effective information delivery systems using information technology.