so how does the traffic feature work?

bkvideography

macrumors member
Original poster
Apr 18, 2007
95
0
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?
 

kevinwiz

macrumors regular
Feb 1, 2007
206
0
socal
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.
 

McGarvels

macrumors 6502
Nov 10, 2006
281
0
Irvine, CA
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.
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...
 

yayaba

macrumors 6502
Apr 24, 2007
297
0
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...
 

kdarling

macrumors P6
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?
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.
 

skubish

macrumors 68030
Feb 2, 2005
2,663
0
Ann Arbor, Michigan
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?
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.
 

CyberGreg

macrumors regular
Jan 2, 2004
135
0
SoCal
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...
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: http://www.dot.ca.gov/dist11/d11tmc/sdmap/travel/travel.php
Looks like they're working on the LA County map:
http://www.dot.ca.gov/dist07/travel/travel_times/

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.
:cool:

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

Xtgirl

macrumors regular
Jul 15, 2007
169
0
how do you get traffic functions on google maps using the iphone..i didn't know you could do this!
 

mrtune

macrumors 6502a
Jun 23, 2007
803
20
I prefer sites like mobi.traffic.com 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 traffic.com but the iphone doesn't support flash, so the regular maps don't load :(.
 

kdarling

macrumors P6
how do you get traffic functions on google maps using the iphone..i didn't know you could do this!
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:

http://manuals.info.apple.com/en/iPhone_User_Guide.pdf
 

Xtgirl

macrumors regular
Jul 15, 2007
169
0
Sigh...I didn't even know there was a manual:( Thanks for the link! I learn new things to do with this thing everyday!
 

kf6oyk

macrumors newbie
Jul 18, 2007
4
0
Here in the Bay Area, I believe that they use FasTrak for traffic data.

Copy and paste from www.bayareafastrack.com

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 www.511.org.
 

mrridiculous

macrumors newbie
Sep 17, 2009
1
0
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.
 

smoge

macrumors regular
Jun 14, 2011
218
1
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.
correct but the iphone dose not have gps, it has gprs. its completely different and dose not require satellites.
 

Laird Knox

macrumors 68000
Jun 18, 2010
1,767
938
correct but the iphone dose not have gps, it has gprs. its completely different and dose not require satellites.
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.