I'm also wondering if the Andes are steeper than the Rocky mountains? Some quick Googling suggests that might be the case but I'm not getting a definitive answe

I'm also wondering if the Andes are steeper than the Rocky mountains? Some quick Googling suggests that might be the case but I'm not getting a definitive answer. Gradual elevation is certainly easier to build roads across than a cliff, and might be another reason there's less east-west divide in North America.