This week Google is expanding their traffic layer to cover all U.S. highways and arterials, when data is available. It uses crowdsourcing.
If you use Google Maps for mobile with GPS enabled on your phone, you can help generate this “live” content. If 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.
Google’s My Location feature takes information broadcast from mobile towers near you to approximate your current location on the map – it’s not GPS, but it comes pretty close (approximately 1000m close, on average). Google combines your speed with the speed of other phones on the road, and across thousands of phones moving around a city, so they get a pretty good picture of live traffic conditions.
Not only can you get live traffic updates, Google Maps lets you select options for viewing the average traffic patterns on a specific day and time, notes ArsTechnica. Say you’re taking a road trip and you’re leaving on Thursday at 5pm — you can now look up the traffic in advance for planning purposes.
Google says to make it work, they 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 they 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).
CommuTweet also lets commuters share traffic updates. You can sign in on the CommuTweet Web site with your Twitter account and save your commuting preferences (for example, New Jersey rail) for easy updating. Or just do it directly from Twitter. Viewing is the same: go to the Web site, or search on Twitter. CommuTweet is subscribed to all the official public transit feeds, so there are plenty of updates even if users aren’t generating them.