Wednesday, April 16, 2008

Google Road Traffic Incidents ahoy!

I have not posted for a long, long while because the confluence of several events has been keeping me busy almost around the clock for the last 5 weeks.

First and foremost, the project I've been working for the last 3 months - the road traffic incidents - has shipped today. It's my first experience building the entire pipeline at Google - downloading the data from 3rd party provider, parsing it, storing the results in a bigtable, writing a spatial index for it, and, finally, publishing it through the maps frontend server. Here's the result:

It's actually kinda fun watching the data in various cities. Seattle is a really, really quiet place. The incidents are mostly construction (there are a few accident icons, but in reality they are all about slow traffic):

Though Seattle is a small place, actual real accidents (as in - collisions) are quite uncommon even in much bigger cities. Here's New York. Here you see a lot of road closures (most of them are periodic, and in the future - eventually we'll figure out how to be more intelligent about displaying them; right now the data we're getting is lacking a lot of details that would allow us to be - but we'll work it out with our provider). There are a few constructions, and slowdowns, but only one of the icons is displaying a collision:

And most other US cities are somewhere between New York and Seattle. Except for one. If you're living in LA, my hat is off to you. The traffic there is real zoo. Yes, there's even one place where almost everyday the sign shows "Animals on the road". Here's a quiet night at LA (believe it or not, during the day time, it's a lot worse). Most non-consturction icons are real collisions. A couple are hit and runs.

The insane amount of construction icons you see here is a nightly event - the authorities deply miriads of crews to do various road maintenance tasks on the roads in the evening, and it lasts through the night. And they report a construction incident for every one of them. During the day, the roadwork in LA clears, leaving mostly just collisions. But a lot of them!

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