If you look at that image (page 4-100 in the 2015 manual) the triangle is labeled 2. Road signs. The 90 mph is labeled 3. Speedometer. I'm pretty sure road signs only display when using the navigation, and I'm not certain I've ever seen road signs actually display in my HUD, although I don't use nav often. I actually used the nav on my drive to work this morning just to test, but didn't see any road signs, just directions. My route isn't complicated though, so there might not have been any important signs to show.