Yeah, the manual mentions that as a possibility and they recommend not using ACC in those situations. Seems like bullcrap to me.
Agreed...I find the ACC system frustrating. Just posted in the Electronics sub-forum that I find the following distance just too close at 75 MPH.
Also, found a similar situation with the Yukon not being able to determine which lane a truck was in (not mine) when we were rounding a gentle curve and applying the brakes hard thinking the truck was in my lane. Not fun at 75 MPH.
Never had this happen before on any other car I've owned with ACC. Hoping there's a software fix that happens soon since it makes the system dangerous. GM should have built in appropriate following distances at high speeds and should have programmed the system much better to determine which lane traffic ahead is in around curves.
It can't be that difficult since other manufacturers make really competent Adaptive Cruise Control systems.