
Ask HN: How Google maps detecting real time traffic? - user7878
I am curious how google maps retrieving real time traffic details so fluently over the globe.
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oblib
Years ago I made a "real time web based traffic map" for a USDOT/MODOT
project. We used traffic sensors made by 3M that sent data to a local 911
center that was also setup under the same project.

The sensors sent traffic counts every few minutes and I used that data to draw
greeen/yellow/red lines of the areas covered on a road map.

[http://multimedia.3m.com/mws/media/362275O/3-monitoring-
traf...](http://multimedia.3m.com/mws/media/362275O/3-monitoring-traffic-on-
bridges.pdf)

~~~
user7878
Thanks man for justification. I'm curious about how currently it being
captured.

Yesterday I was driving way home back and there were road blockages due to
heavy rain and an accident. I just checked on map for traffic and it's nearly
accurate to real traffic of vehicles. My commute routes does not consist of
those type of devices/sensors per my understanding and observation. It's non
metro city of India.

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prostoalex
1) Government data [https://opendata.stackexchange.com/questions/1767/data-of-
ve...](https://opendata.stackexchange.com/questions/1767/data-of-vehicle-
traffic)

2) Waze, Google Maps turn-by-turn

