Rescheduling of daily activities and associated travel in response to unforeseen events such as travel delays is receiving increased attention in the context of traffic management. In this paper we describe the results of a stated adaptation experiment held among a large sample of individuals through a web-based questionnaire, to estimate parameters of such dynamic behaviour. In the experiment subjects indicated their response to a reduction in available time for a planned activity in a number of hypothetical situations. A mixed logit model was used to estimate subjective preferences for adapting in certain ways conditional upon activity attributes and socioeconomic variables. The results indicate that location and transport-mode adaptations are rare compared with duration adjustment or postponing (or cancelling) the activity, dependent on the relative size of reduced time. Socioeconomic variables and activity attributes also play a significant role.