so how does the traffic feature work?

Discussion in 'iPhone' started by bkvideography, Jul 17, 2007.

  1. macrumors member

    Apr 18, 2007
    how is it updated? if someone has a gps device in their car, does the satellite read how fast they are going and that updates the traffic info?
  2. macrumors 6502a


    Apr 3, 2003
    Studio City
    red means stopped
    yelow means slow
    Green means go, clear
  3. thread starter macrumors member

    Apr 18, 2007
    well i knew that, but i wanted to know how it actually werx....
  4. macrumors regular

    Feb 1, 2007
    there are sensors under all the socal freeways that give data. you can see the cracks on the road when you drive over them. thats how it works here. other areas might be different.
  5. macrumors 6502


    Nov 10, 2006
    Irvine, CA
    I think he means do you have to refresh the iPhone to get updated traffic speeds or does it do it automatically every so often. A good question as I've been wondering this myself. Traffic sucks in so cal, especially the 605/5/405. Oh well...
  6. thread starter macrumors member

    Apr 18, 2007
  7. macrumors 6502

    Apr 24, 2007
    San Francisco Bay Area
    I've been wondering that myself. How often is it updated anyway?

    Take today for example. I looked at the Traffic data on Google Maps and it showed that much of the freeway I would be taking was Red. But then I checked SigAlert and that said most of it was Green with some rough spots.

    I then drove it and found that my experience matched SigAlert's. So much for traffic info from the Google Maps...
  8. macrumors demi-god


    Jun 9, 2007
    Device engineer 30+ yrs, touchscreens 24+.
    Just a note: GPS is one-way, from satellite to receivers. Nothing transmits back to the satellite.

    Major cities have speed sensors that collect traffic data. The database view to the public is updated usually about once a minute.

    No idea how often or if it's updated on iPhone.
  9. macrumors 68030


    Feb 2, 2005
    Ann Arbor, Michigan
    Those diamond patterns cut into the road you see every so often. It measures the speed and transmits it to a local agency. Google aggregates the data from major cities. I don't know how often Google maps gets updated but it seems accurate.

    And as others have said, GPS devices only receive not transmit.
  10. macrumors regular

    Jan 2, 2004
    Wouldn't it really depend on each of the sites definition of Red, Yellow and Green? On SigAlert, it's:
    Red - 1-14
    Yellow - 15-34
    Gray - 35-54
    Green - 55+

    I don't know what Google uses but for Southern California; I've found this site to be very helpful (when all the sensors are reporting).
    San Diego area:
    Looks like they're working on the LA County map:

    Anyhow... I'll try and compare Google and the CA DMV site to see how close the times are. I'm not too concerned if the colors don't match, just if the travel times are off.

    Edit: Here's a nice map of the Traffic areas that Google has:
    Link Here
  11. macrumors regular


    Aug 27, 2006
    Minneapolis, USA
  12. macrumors regular

    Jul 15, 2007
    how do you get traffic functions on google maps using the iphone..i didn't know you could do this!
  13. macrumors 6502a

    Jun 23, 2007
    I prefer sites like over google maps traffic info. Dedicated traffic sites will provide much better and more detailed info than google.

    Sucks to have to use the mobile version of but the iphone doesn't support flash, so the regular maps don't load :(.
  14. macrumors demi-god


    Jun 9, 2007
    Device engineer 30+ yrs, touchscreens 24+.
    I can't believe they don't include the manual in the device :rolleyes:

    Or at least have an HTML linked version online. Is there one? So much for cutting edge management ideas!

    Anyway, see the iPhone manual in the section on Applications / Maps:
  15. macrumors 6502

    Jan 2, 2007
    Carlsbad, CA
  16. macrumors regular

    Jul 15, 2007
    Sigh...I didn't even know there was a manual:( Thanks for the link! I learn new things to do with this thing everyday!
  17. macrumors newbie

    Jul 18, 2007
    Here in the Bay Area, I believe that they use FasTrak for traffic data.

    Copy and paste from

    How is my FasTrak® toll tag used for traffic information purposes?
    The toll tag may be read to provide anonymous traffic flow data to the Metropolitan Transportation Commission’s ‘511’ project, which is a toll-free phone and Web service that consolidates Bay Area transportation-related information – providing up-to-the-minute information on traffic conditions and incidents. FasTrak® users remain anonymous through the use of encryption software that scrambles each FasTrak® toll tag ID number before any other processing happens. If you do not want your toll tag read for these purposes, place the toll tag in the special Mylar bag provided to you when you are not using it for payment of tolls at a toll plaza. The Mylar bags can be requested from the Customer Service Center. If you would like additional information about ‘511,’ please visit
  18. macrumors newbie

    Sep 17, 2009
    On the NY Thruway, I see a sensors attached to overpasses that I think are monitoring speeds of each vehicle. There's plenty of traffic cams that can probably sense speeds too. Here's a full explanation of the google traffic view which really shows how big of a system it really is.
  19. macrumors regular


    Jun 14, 2011
    correct but the iphone dose not have gps, it has gprs. its completely different and dose not require satellites.
  20. macrumors 65816

    Jun 18, 2010
    Wow, way to resurrect an old post with incorrect information.

    You did get it right that GPS and GPRS are not the same thing but the iPhone most certainly does have GPS.
  21. macrumors 603

    Apr 24, 2010
    Newbury, UK
    hahaha great joke. :D lolwut? you were being serious?? :eek:

    i think you should go tell apple as they have it totally wrong if you're right...

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