How does the NAV system collect data to show where traffic has slowed of stopped, indicated with green, yellow or red lines on the screen. What is telling the system that traffic has slowed or stopped.

I am impressed with how well it seems to work.

 

The data comes from the HD radio signal. If you are in an area of poor or no HD reception, it will use the App Suite app on your phone for the data.

 

Thanks but I know that. I want to know how the HD radio get this information to put on our screen. How does it know traffic has slowed or stopped? What is the method of data collection.

 

Google use tracking of mobile devices. My guess is that this is similar - maybe data from a wireless carrier. Usually traffic data on my Lexus navigation are still worse comparing to Google maps. So the source is probably different.

 

Google uses a few sources for traffic data.
1. Local highway authorities ( traffic sensors), most of which were installed by gov't transportation agencies, and this system is more reliable than smartphones.

2. Other data is from people using google maps aaps on certain smartphones and enable to relay location data back to google.

 

So you are saying it would be Android phones using Google maps that give the HD NAV system it's data?

I am impressed with it accuracy.