Google Maps bases its traffic views and faster-route recommendations on two di
fferent kinds of information: historical data about the average time it takes
to travel a particular section of road at specific times on specific days and
real-time data sent by sensors and smartphones that report how fast cars are m
oving right then.
Data from these sensors can be used to provide real-time traffic updates, and,
once collected, the information becomes part of the pool of historical data u
sed to predict traffic volume on future dates. However, sensor data was largel
y limited to highways and primary roads because the sensors were typically ins
talled only on the most heavily traveled or traffic-prone routes
As more and more drivers use the app, the traffic predictions become more reli
able because Google Maps can look at the average speed of cars traveling along
the same route without misinterpreting someone's morning coffee stop as a tra
ffic jam. If Google Maps doesn't have enough data to estimate the traffic flow
for a particular section of road, that section will appear in gray on the tra
ffic layer
Facts:
1. Historical data
2. Your smartphone
:)