Function of travel code
The function of the trip code is to monitor whether people have been to a certain place, and to remind people whether they have been to the epidemic danger zone through the change of color. In order to effectively prevent and control the epidemic situation in COVID-19 and provide a basis for tracking the epidemic situation, the relevant state departments have developed a travel code, which records people's travel by using big data records. If people stay in a place for more than four hours, the travel code will record where people have been.