The bright side of sitting in traffic: Crowdsourcing road congestion data

Tuesday, August 25, 2009 | 8:40 AM

This post is the latest in an ongoing series about how we harness the data we collect to improve our products and services for our users. It is cross-posted from the Official Google Blog. - Ed.

What if you could do a little something to improve the world during your daily drive to work? Here are a few ideas: tell everybody in the city when you're stuck in slow-moving traffic; warn the drivers on the freeway behind you that they should consider an alternate route; tell the people still at home that they should spend another ten minutes reading the morning news before they leave for work; tell your city government that they might want to change the timing of that traffic light at the highway on-ramp. Of course, you can't just get on the phone and call everybody, and your one traffic report from your one spot on the road might not help much anyway. But if everybody on the road, all at once, could tell the world how fast their car is moving, and we could make it easy for anybody to check that information on their computer or cell phone, well — then we'd be getting somewhere.

If you use Google Maps for mobile with GPS enabled on your phone, that's exactly what you can do. 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. We continuously combine this data and send it back to you for free in the Google Maps traffic layers. It takes almost zero effort on your part — just turn on Google Maps for mobile before starting your car — and the more people that participate, the better the resulting traffic reports get for everybody.



This week we're expanding our traffic layer to cover all U.S. highways and arterials when data is available. We're able to do this thanks in no small part to the data contributed by our users. This is exactly the kind of technology that we love at Google because it's so easy for a single person to help out, but can be incredibly powerful when a lot of people use it together. Imagine if you knew the exact traffic speed on every road in the city — every intersection, backstreet and freeway on-ramp — and how that would affect the way you drive, help the environment and impact the way our government makes road planning decisions. This idea, which we geeks call "crowdsourcing," isn't new. Ever since GPS location started coming to mainstream devices, people have been thinking of ways to use it to figure out how fast the traffic is moving. But for us to really make it work, we had to solve problems of scale (because you can't get useful traffic results until you have a LOT of devices reporting their speeds) and privacy (because we don't want anybody to be able to analyze Google's traffic data to see the movement of a particular phone, even when that phone is completely anonymous).

We achieve scale by making Google Maps for mobile easy to install and use, and by making it easy for people to provide information about their own vehicle speed. There's no extra device to plug into your car and no extra software to buy. Google Maps is free and works with most cell phones, and the number of cell phones with GPS is rising every day. Some phones, such as the T-Mobile myTouch 3G and the Palm Pre, come with Google Maps and traffic crowdsourcing pre-installed (the iPhone Maps application, however, does not support traffic crowdsourcing). Google is fortunate to have a lot of people using our products, and that scale helps make our products better.

We understand that many people would be concerned about telling the world how fast their car was moving if they also had to tell the world where they were going, so we built privacy protections in from the start. We only use anonymous speed and location information to calculate traffic conditions, and only do so when you have chosen to enable location services on your phone. 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. We take the privacy concerns related to user location data seriously, and have worked hard to protect the privacy of users who share this data — but we still understand that not everybody will want to participate. If you'd like to stop your phone from sending anonymous location data back to Google, you can find opt-out instructions here.

We've already been able to provide useful traffic information with the help of our existing mobile users, but we hope that is just the start. As GPS-enabled phones and data plans get less expensive, more people will be able to participate. Crowdsourcing traffic gives us a way to harness bits of location data from our users and give it back to them in a form they can use to make impactful decisions that affect their free time, their pocketbooks and the environment. The more people use it, the better it will get. So next time you're sitting in morning traffic, turn on Google Maps for mobile and let someone else know they can hit the snooze button one more time. Tomorrow morning, they might do the same for you.


21 comments:

colin said...

Some love for Canada please?

Jonathan said...

iPhone not supported, but can we use the Latitude web app to contribute?

Brian said...

How do you know if someone is actually driving on the highway versus just hiking, walking or biking on a nearby trail or shoulder? Wouldn't that throw off the calculations quite a bit when there are not many data points being sent?

timbro said...

canada please.

Will Shaver said...

1. Bikers?
2. Does the most recent maps on the G1 do this?
3. Woo!

Kenny said...

Where is the updated Google Maps for Palm Pre? I can't see it.

ruffneckc said...

Keep up the good work Google....I don't mind joining in. It's just that GPS drains the phone battery so much now that I (and others I suspect) will not want to do this all the time.

Keep working on more efficient battery use on Android and the numbers of participants will rise as a result.

martin said...

Fantastic! Bring it to the UK ASAP please!

Martin

Roshantee said...

I'd love to try this out but the Android google maps traffic layer/feature is BROKEN. Any update as to when this known bug will be fixed?!?

Mihail said...

Hey!
It is like Yandex traffic!! But it's not only for Russia.
It is best idea for Google to use people's GPS to show traffic.

Chuff said...

I dunno google, I'm still getting "low on memory, traffic has been turned off" errors which makes using this app while moving useless.

I'm using waze instead, plus I'm getting pac-man points now! :P

Patrick said...

I would love to contribute. Now we need more GPS options within the Google Maps program. At the moment, my blackberry likes to turn of the GPS to save battery. We need to be able to tell it not to turn the GPS off if plugged into a power source or only power up the GPS every so many minutes. Maybe in version 3.3? Lets hope. Keep up the great work Google!

Carl Sian said...

My iPhone 3GS shows the overlay data. What part is not supported? Sending location data in?

Unfitguy said...

Seems to be on Google Android maps now, would like a one touch feature/shortcut to be able to automate this from the home screen

John said...

Awesome! Now let is drop pins that have a short life span for important things like say a wreck, road debris, or even better, a cop. You know, in case we need help. :D

Paul said...

Is anyone working on Google vs Verizon Blackberry 8330 interface issues?

John said...

Hi Dave, Is google making the raw traffic data available to the public in any other form? I am a graduate student working on stochastic optimization problems and would find the data incredibly helpful for my thesis.

RoShFè said...

Support for Canadian Roads would be much appreciated! Please!

Alex said...

This is great and I hope it succeeds, but just so people are aware Nokia was doing it some time ago: http://berkeley.edu/news/media/releases/2008/02/08_gps.shtml
and another research project elsewhere was too. Lets hope all these systems take off and indeed merge with one another to give the most accurate traffic forecast. And lets have live rerouting around traffic conditions too please.

Etienne said...

This is a nice idea, proposed by the Jamdroid application on Android: http://jamdroid.blogspot.com/

But yes, only Google will have the way to touch a large enough basis of users to get a relevant accuracy.

Joe said...

Since Google is profiting from freely contributed public data, it would be great if Google also made the gathered data (in raw form) available to the public. Any plans for this?