Can anyone tell me if it's possible to skip the lines at the Coliseum using a Roma Pass?
You skip the ticket line but not the security-check queue: everyone has to go through that one.
Thanks Kathy. Is the Security check line clearly marked?
Yes, it is clearly marked: it is the long line with a big sign that says "Skip the Line". This problem has been reported over-and-over and you might find this post from a few weeks ago insightful.
You might want to hook up with a tour guide. The wait at security is shorter.