Mobility Tracking refers to the collection of participants’ mobility data with the help of mobile apps or devises, e.g. through their mobile phones or other daily-use wearable devices. There are two types of Mobility Tracking: Active Tracking and Passive Tracking. Active Tracking requires participants to share their data actively or to authorize some software on their mobile devices to collect and share data. Passive Tracking does not need participants’ consent, and planners collect participants’ data from mobile network operators. By cleaning and analyzing the data collected through Mobility Tracking, people’s travel behaviors, place preference, etc., can be known. The legality of collecting data without the user's consent should be discussed.