Roundabouts are becoming more popular as you know. They can also mean a more dangerous situation for bike riders. I'm going to give the one on Hwy. 3 just a few miles south of Rosemount as an example. Since it's a single lane one you need to pay attention to vehicles behind you just before entering the circle. Look over your left shoulder and if there's a vehicle coming up on you you have 2 choices to make in a hurry. Either slow down and let them enter the circle 1st, or single with your hand that you are taking up the whole lane. The reason for this is to not get pinched between you and that car with no escape route. Remember that "two objects can't occupy the same space at the same time". The two lane roundabouts are much safer. Be careful out there.