The back-straight crest at Road Atlanta has been lowered and smoothed out to decrease the chances of cars losing downforce and flipping over backwards. The crest was formed during construction of the track in 1970, when crews encountered a rock formation and paved over it instead of removing it, due to time considerations and an approaching Can-Am car race. During the years at least four race cars have flipped over backwards at the top of the crest. Work to smooth the crest began at Road Atlanta the week before Christmas and was completed early in January. The crest is now about 4 feet lower and the transition from the crest to the rest of the straightaway is smoother.