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How Does the Google Maps Traffic Feature Work? Where Does the Data Come From?

written by: •edited by: Josh McWilliam•updated: 9/24/2010

If you've used the Traffic view on Google Maps, you must have wondered how Google gets and displays live traffic data. This article explains where the data comes from currently as well as where it will be coming from in the future.

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    Google Maps Real-Time Traffic View

    Google Maps has offered the ability to view 'real time' traffic reports for a while now.  I have always wondered where it got its information from, and somewhat ignored it due to my doubt that it was actually accurate.  Recent news about some cool enhancements they have made recently to help crowdsource the collection of real time traffic data via mobile phones caused me to finally look into where the data came from in the first place.

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    How DOT Sensors Help to Report Traffic Conditions

    Most major metro areas in the US have sensors embedded in their highways. These sensors track real time traffic data.  Easy to miss at high speeds (hopefully anyway, traffic permitting), more commonly noticed may be the similar sensors that often exist at many busy intersections that help the traffic lights most efficiently let the most amount of people through.  These odd, rectangular cut-outs in the road are still easy to miss in a car, but much more noticeable if you ride a motorcycle.  

    The information from these tracking sensors are reported back to the Department of Transportation (DOT).  The DOT uses this data to update some of the digital signs that report traffic conditions in many metro areas.  They also openly share much of this frequently updated data out, which is how Google reportedly gets this data for the major highways in the metro areas it offers traffic reporting for.

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    Using Mobile Phone GPS Data to Track Average Speed

    Many reports have come out today noting that Google is now offering traffic reports for secondary roadways, routes not necessarily containing DOT sensors. The way in which they are doing this is pretty cool, and may prove to be a way to some day provide quality real time traffic data for all roadways.  

    If you have a Google Maps installed on a mobile phone with GPS capabilities enabled, your location can be transmitted to Google in real time, allowing the them to determine the fact that you are on a particular road and traveling at a certain pace. For us early adopters, Google offers this positive outlook on sitting in traffic. If this functionality exceeds your "big brother" threshold, you can opt-out of Google's My Location system on your mobile phone.

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    Challenges Moving Forward

    There are several challenges Google, or similar solution providers, will face before making this method of using user's mobile phones a source of quality real time traffic data on a large scale.

    Mobile Phone Adoption

    The larger the data set Google can draw from the more accurate results will be. The use of smartphones with GPS capability is certainly rapidly expanding, as is the use of its Maps application on smartphones. However, the large scale adoption of both cases is likely to be more distant than anyone reading this article anywhere near its publish date is likely to accept.  

    Distinquishing Motorists from Pedestrians

    I suspect it will be hard to accurately distinguish people in cars on the road from those that are walking along side it, or perhaps using alternate forms of transportation such as a bike (or who knows, even the subway). I suspect Google's move to open this up to only major secondary roadways is based in part on that. Making sure they pick roads that have a degree of traffic on it sufficient to out-weigh any pedestrians on it is crucial to accurate results.

    Processing Power and Algorithms

    Probably Google's least worry, it certainly does take time to rally the appropriate hardware and engineers behind a solution to process so much real time data (another reason for keeping it to major roadways).   

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    The Future of Reporting Data via Smartphones

    The use of mobile smartphones is expanding rapidly. I suspect that Google, given the potential traffic that quality of real time traffic reports could generate, will throw their weight behind this, resulting in the processing power and algorithms needed to provide a useful service to the greatest degree possible (which will be worlds more than we currently have). Good luck to any potential competitors given what I project will be a massive adoption of mobile Google Maps apps, regardless of cell phone carrier or platform.