Abstract: Objective Due to its minimum burden for respondents,passive GPS has become a promising methodfor collecting individuals’activity-travel behavior data.However,passive GPS only provides informa-tion on time,position speed of movement,etc.Individuals’activity-travel behavior information con-cerning what(types of activities and trip purposes),where(place where activities are collected as wellas trip origins and destinations),when(starting time,duration as well as trip arrival and departuretimes)and with whom activities are conducted and what transportation modes are used must be de-duced from the raw data of passive GPS.This has been the major obstacle for applying passive GPSfor collecting activity-travel behavior data.In the past years,much research attention has been direct-ed toward develoing methods to derive activity-travel behavior information from passive GPS.Thepurpose of this paper is to provide an overview of the state-of-the-art developments in this researchfield.The paper first traces the developments of activity-travel data collection methods;emphasis willbe placed on summarizing the recent developments of post processing methods from GPS raw data.Pros,cons and problems of the existing methods and algorithms for detecting individuals’activity-travel behavior information from passive GPS data will be analyzed and discussed.Prospects and po-tential areas for future studies in this field as well as future directions for using modern ICTs to collectactivity-travel behavior data in general will be suggested.