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Google Shows Street-Level Traffic On Some City Maps

Yesterday, Google added the latest in a long list of new features to its online mapping service: street-level traffic data in major cities. On both its full-size site and its mobile-phone applications, you're no longer limited to seeing that, say, the Dulles Toll Road is running slow between Spring Hill and I-66 (well, duh); you can now also check the traffic on "arterial" roads such as Chain Bridge Road, K Street and Wisconsin Avenue.

Google doesn't say how many cities get this treatment, but the Washington area is among them, as you can see in the screen grab at right. Here and in other places blessed with this extra level of traffic coverage, Google now has a sizable advantage over competing map sites from AOL, Microsoft, Yahoo and others -- not to mention GPS-navigation programs that don't even try to factor in congestion.


But how does Google know this? A post on Google's company-wide blog explains that it gets this information by collecting anonymized data from users of its phone mapping software:

When you choose to enable Google Maps with My Location, your phone sends anonymous bits of data back to Google describing how fast you're moving. When we combine your speed with the speed of other phones on the road, across thousands of phones moving around a city at any given time, we can get a pretty good picture of live traffic conditions.

Yes, Google's mobile-privacy policy allows for that, in somewhat vague terms. That blog post goes on to say that Google takes extra steps to wash traces of your identity out of its aggregated data:

We use our scale to provide further privacy protection: When a lot of people are reporting data from the same area, we combine their data together to make it hard to tell one phone from another. Even though the vehicle carrying a phone is anonymous, we don't want anybody to be able to find out where that anonymous vehicle came from or where it went -- so we find the start and end points of every trip and permanently delete that data so that even Google ceases to have access to it.

Is that enough privacy protection for you?

For many of you cursed with a traffic-choked commute, however, the more important question may be: How accurate are Google's reports? Take a look at its data for the routes you drive on regularly and report back in the comments if they look right to you or not.

By Rob Pegoraro  |  August 26, 2009; 11:38 AM ET
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There are so many ways to do traffic apps, cameras on news web sites, VDOT and all. I still rely on "traffic on the eights" on trusty WTOP.

Posted by: tbva | August 26, 2009 11:47 AM | Report abuse

Is it any good? On a laptop or desktop, it takes far too long for google maps to load. I couldn't imagine the wait on a cell phone.

Posted by: ummhuh1 | August 26, 2009 12:33 PM | Report abuse

How does Google know that I am not walking down one of these streets with my phone, rather than crawling along in the right lane on 14th street? Would that not affect speed data?

Posted by: vtavgjoe | August 26, 2009 12:41 PM | Report abuse

Wonder whether the recent court decision forcing Google to release data in a slander case might undermine those privacy provisions in some way? Granted, you'd have to get a court order awfully quickly, but once GoogleCourts makes its debut, who knows?

Posted by: mjohnston1 | August 26, 2009 4:59 PM | Report abuse

mjohnston1 -- Google Courts is only currently used by the CIA in trying to locate both friendly judges as well as unfriendly terrorists. LOL

Is this a part of the Google App that also allows one to track a stolen phone, or find all your buddies after they get drunk on the weekend ???

Posted by: | August 26, 2009 6:46 PM | Report abuse


I find WTOP almost useless most of the time. Usually it just tells me what I already know (trying to get anywhere during rush hour in DC stinks). It rarely identifies local delays. To me it really only helps if you are going through the area and have multiple routes to choose from.

Posted by: slar | August 26, 2009 7:08 PM | Report abuse

I have not been able to use Google maps with Firefox (up to date) for a while now.
The initial map (North America) loads, but nothing else. I get a message of "Still loading ... Slow ? Use the troubleshooting guide or basic HTML"

I looked at the troubleshooting guide which describes several steps to change the browser settings (handling of JavaScript).
But why should I muck around with my browser's settings for JavaScript? Google. please make your mapping program compatible with Firefox !

Posted by: observer31 | August 27, 2009 8:48 AM | Report abuse

I too use WTOP and, while I agree it frequently tells me what I know, major roads are clear, traffic running, heavy traffic on the wherever, etc., there's a limited amount of time to cover a lot of area. Not trying to sound like an apologist for WTOP, but if you're travelling to or from Arlington to the north or east of Washington, you care don't care about Montgomery County, anything east of the Wilson Bridge. If you're living near Andrews Airbase and you're traveling to Tyson's Corner, or coming from the Baltimore area going towards Montgomery Shopping Mall or Lake Forest, you could care less about downtown traffic, the Roosevelt Bridge, etc. Add to that, even if there's a major accident and roads are tied up near Clopper Road and Quince Orchard, it's very important to those who travel the area but useless to people who aren't in the area, let alone those who have no idea who, what or where Clopper Road is, even if it is a major thoroughfare. And, even if WTOP or any other station was full time traffic, you probably wouldn't want to hear five minutes of Maryland followed by five minutes of DC if you're in and around Virginia; you'd consider the information useless. Which means they satisfy the masses in a general way; it's cotton candy for your drive. The question then becomes, how local should the traffic reports be? If you're doing local, in and around Gaithersburg Square, it would be great; unless I was off to the side of Gaithersburg Square heading in the opposite direction. Sorry, while I agree local would be good, how local can you be without being foreign or distant to everyone else.

Posted by: Dungarees | August 27, 2009 9:24 AM | Report abuse

I'm confused about the "yesterday" part of the blog/announcement: I've been seeing local, street-level data in Google Maps for several weeks now, at least for downtown DC...? Was that just "beta," and now it's considered operational? While I now see more street-level data for the DC metro area, it doesn't seem like Google flipped any switches here. Did I miss something?

Even better than using straight Google Maps for traffic, is's web application, which combines Google Maps info with their network of webcams. While I still listen to and love WTOP, if you've got a high-speed connection, on a desktop ( or even their mobile site (no maps or cameras, but good data) is the way to go.

Posted by: TheBorg | August 27, 2009 10:30 AM | Report abuse

Would be great if could go the next step and just be able to receive text alerts (like about user-designated local areas instead of having to look at an actual map.

Posted by: mediajunky | August 27, 2009 10:37 AM | Report abuse

@observer31: it must be your system. It works fine with my versions of FF, 3.0 and 3.5, on both Linux and Winblows.

@vtavgjoe: Your data would probably be thrown out b/c it would be considered an outlier compared to the other data for the area.

Posted by: JorgeGortex | August 27, 2009 12:38 PM | Report abuse

Very interesting. I wondered how that worked. The depicted traffic conditions seem generally good to me.

Posted by: Bitter_Bill | August 27, 2009 1:48 PM | Report abuse

I wasn't as clear as I should have been. I mean I find the traffic results for DC accurate (instead of good -- wish they were!).

Posted by: Bitter_Bill | August 27, 2009 1:58 PM | Report abuse

@observer31: there is a conflict between the Skype extension for Firefox and Google Maps under Firefox. Disable that extension and you'll be in business. I had the same problem.


Posted by: jaepstein63 | August 27, 2009 2:58 PM | Report abuse

I have been using traffic on (mobile) Google maps for a while, and while I love it it's not always that accurate. I'd give it a B-minus for accuracy.

Posted by: jaepstein63 | August 27, 2009 3:00 PM | Report abuse

Thanks for replies.

I looked into the problem and here is the cause :
I use NoScript and allow sites individually and temporarily as needed.
For Google, and, of course, Google maps, I allowed Google. However, I also needed to allow gstatic and the problem went away.

Had similar problem with morningstar. Besider I also needed to allow to be able to view all content.

Posted by: observer31 | August 27, 2009 4:39 PM | Report abuse

Anyone know why Facebook is down?

Posted by: bs2004 | August 27, 2009 5:29 PM | Report abuse

Google has it's own satellites, so I'm sure google will do better than other opponents on Street-Level Traffic.


Posted by: softwaresoda168 | August 27, 2009 11:26 PM | Report abuse

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