Integration of traffic data with navigation systems occurs in many different ways.
According to Consumer Reports, the data may be transmitted through Bluetooth, FM, or XM.
In 2006, Clear Channel made a deal with BMW to supply traffic data for the carmaker's navigation units.
According to GPS Review, the suppliers of this data to the navigation units get their own data from "road sensors, local departments of transportation, data collected from operators of large fleets of vehicles, and other manual sources such as traffic helicopters and listening to police scanners."
Patents have also been taken out for services that will collect movement data from GPS units on the road to determine current travel time between various points; an example is patent number 5933100.