I agree that it is inconsistent, but as noted, turn on dynamic routing. The route preference (fastest, most efficient, shortest) may also make a difference. My biggest gripes are Charlotte always has traffic warnings so I tend to ignore the red triangle. Also, when it reroutes, it thinks you no longer have a traffic issue and displays no red triangle to warn of an issue. I have driven straight into a mess until it pops up, no detour possible.

Lesson: Always watch your arrow display or instructions on the HUD.

__________________
Richard
Sir Snaps-a-lot, 9 Time Dragon Slayer (54 runs!)
2011 X5 50i Alpine White, Biege Nappa /Lt Poplar M Sport
2009 Z4 35i, Black Sapphire/Ivory-Black/Anthracite

Gone but not forgotten: '08 550i, '06 X3, '06 650i, '02 M5, '99 540i