This paper presents a method for generating origin–destination (O-D) matrices with the use of floating phone data, that is, data generated from mobile phones moving through a study area. Mobile phone signals recorded in the cellular phone network are used to derive time–space trajectories of moving mobile phone devices. The start and end points of each trajectory determine the origin and destination zone. Link counts are used to project the sample of mobile phone movements to the broader movement of cars, trucks, and rail passengers. With results of a clustering process of traffic counts, O-D matrices for typical traffic days are computed. The resulting O-D matrices can be used for a long-term traffic state forecast.