When I have the GPS on, sometimes it says, "Traffic Jam Ahead".
I continue driving and never encounter any slow traffic.
How far ahead will the GPS find traffic on my route?
What is the farthest it will detect traffic?
There's a firm ware update out that addresses the issue of better updating of traffic alerts. I had it installed last week at dealer but have not experience and effect yet because we haven't been on the interstate and utilized the traffic alerts.
On a recent trip to AZ for Spring Training, my nav alerted me to "traffic jams" in the middle of the desert but stayed silent when I approached gridlock through Denver. After driving 500 miles from Albuquerque, it was frustrating that it did nothing to warn me about Front Range bumper-to-bumper. Maybe it considered the traffic "normal" for Denver these days....
The alert comes from the Sirius XM Traffic and weather feature. I had a 4 month trial of the music feature but it turns out I had a three year "trial" of the traffic and weather. The information is updated from various sources such as google maps traffic and Waze traffic and various other means, and can take some time to reset back to normal traffic by the time it gets pushed to Sirius XM and finally your vehicle.