eli5 – How do applications like Google Maps and Apple Maps know when there is a traffic jam? Where does the information come from?
In: Technology
In the commercial space, there are many companies that offer fleet tracking services. These typically include a small GPS/cellular transmitter device that sends data about the vehicle on a relatively short interval (@90 seconds). The data sent includes the coordinates, speed, direction, and often additional sensor data such as hard braking, hard acceleration, hard cornering, ignition state, etc.
After using this data in support of the tracking service, it is often anonymized and re-sold to companies that specialize in aggregating traffic data. These companies then use the data to establish the average typical speed of a road segment at various times of day. With this knowledge, they can then look at what the near real-time data is indicating to detect whether traffic is slower than this average and by how much. The direction (or heading) data further identifies which lane of traffic is impacted.
While cell-phone data may certainly be part of the data collected, user privacy preferences, and battery life likely mean it’s a smaller fraction of the overall data being analyzed.
I know this because I was a lead developer for a major tracking platform and was involved with the integration with a traffic monitoring company. In our case, it was a trade as the traffic company returned the posted speed data for a given road segment which we could then use to identify speeding events for our tracked vehicles.
Latest Answers