Google maps is very good at predicting traffic. But how does it get this information?
If you have an android phone or an iPhone with Google maps open and location services enabled, then the app is anonymously sending real-time data back to Google. It uses this info to calculate how many cars are on the road and how fast they are moving.
So the more people using the app, the more accurate the traffic data. Google also incorporates traffic data from an called Waze which the company bought for $1 billion in 2013 and it monitors traffic reports from local departments of transportation.
Google keeps a history of traffic patterns on specific roads so it can predict what traffic will be like at a specific time and maps will tell you why it gave you a specific set of directions to help develop your trust in the app.
If you don’t feel comfortable with Google monitoring your every move, you can easily opt out by turning off location services. But if everyone did that, the data might not be as accurate.