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Does anyone know how accurate the Google traffic report is on the maps ? Where does that info come from ?
It comes from the Metro-DOT info. Ever see those diamonds carved into the freeway? It measures vehicle speed and reports back. The only question is how often Google updates the info.
 
Major cities across the U.S. have sensors throughout their highways, and they use this to measure the average vehicle speed in various sections. The data is used to automate warnings on highway signs, control traffic light flow, etc.

The data is made available for public use, and is usually updated every two minutes or so.

I do not know how often Google maps checks it.
 
This worked for me. I had a 50 mile commute and was stuck in stop & crawl traffic. As I was just sitting there I decided to check traffic.
Red all the way. Sadly, this was accurate.
 
It comes from the Metro-DOT info. Ever see those diamonds carved into the freeway? It measures vehicle speed and reports back. The only question is how often Google updates the info.
I always thought those diamonds meant "HOV lane."
 
this is not working for me sometime. Sometime I was on the map and it gave me the error, like offline message. And it took awhile to get back on. Any one got that?
 
I always thought those diamonds meant "HOV lane."

There are the big white paint diamonds which mean HOV lane, then there are the diamond-shaped cuts in the pavement. Those hide the sensors. (You also see them at traffic-controlled intersection signals.) They aren't painted, they're just cut-then-patched bits of pavement, where the cuts have been made in (usually) a diamond shape.
 
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