All cell phones are tracked in real-time
If, in the USA, your phone can connect to a network cell tower, its location is being tracked in real-time whether you are 'using' it or not. This functionality was actually mandated by US lawmakers years ago. The excuse, ironically enough given the idiotic premise of this movie, was so 911 callers could always have their position located.
Since that time, the US government has informed TV and film-makers that it does NOT want the audience to be reminded of this fact, and actually financially rewards networks that lie in their productions, and state that phones are not location tracking devices.
You cell phone is NOT tracked by real GPS, although if a real GPS chip exists in your phone, and is currently active, that information may be passed to the local cell tower as well. Your cell phone reports its position, multiple times an hour, by constantly connecting briefly to all local cell towers, allowing a VASTLY more sophisticated form of the old technique of 'triangulation' to work out its location to within several yards.
The NSA, as well as receiving and storing copies of all cell phone conversations, also receives the complete real-time data stream that describes the location of EVERY cell phone that currently has any power and is within reach of a tower.
Most larger police departments can also access this data (via the phone companies) on request.
Ask yourself this. Why does your government want you to watch films like 'The Call' and draw a completely false conclusion about the State's ability to track you? I should also point out that vehicles are tracked by the RFID chips that have been embedded in tires for many years now. Your tires become your vehicle's 'fingerprint', and the license-recognition cameras you hear so much about simply connect a license-plate identity to that 'fingerprint'. The under-road RFID readers are invisible to the driver, infinitely cheaper and far more reliable than any camera system. In the larger cities, every major road and junction knows EVERY vehicle that passes through them via RFID, and the record of such journeys again sits on a permanent government database.