On a ride into San Francisco one day my brother pulls out his smartphone, hooks it into a cradle on the dashboard. So let’s check out the traffic on Google maps! Up pops the live traffic situation — the freeway is green if it’s smooth sailing, yellow if it’s slow and – 10 points if you can guess the color – if it’s stop-and-go.
How do they figure that out? Does the satellite look down, count the number of cars or their speed, judge the traffic flow, and upload the color? No, Dave tells me, it’s a clever app that takes advantage of the fact that most Californians have two things in common: they have GPS-enabled smartphones and they’re obsessed with avoiding traffic jams. Here’s an explanation of how it works from an official Google blog back in August 2009:
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.
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