Two companies are said to have a system monitoring traffic on roads and highways which is based on tracking the signals of cellphones that are inside cars while on the road. The mode of operation of two systems is basically the same although there are some piculiarites to each system that differentiate them. IntelliOne and AirSage use data provided by wireless companies from their respective cellular towers. They calculate the position of each phone about twice a second when it's being used and once every 30 seconds when it's not.
Some providers expect to get customers who would give the possibility to get alternate route data sent to them in case of heavy traffic for a monthly fee; although there are privacy advocates who insist that cellular providers should not be allowed to track their customers while on the road.