Re: Roundabout rules, signals and observation.
When approaching the circle, you must look to your left and yield to any traffic coming from that direction. If none, proceed into the circle. If you are turning immediately right out of the circle, signal right. If you are continuing around the circle, you should have your left signal to indicate to drivers waiting to enter that you are continuing left in the circle, which tells them it is not safe for them to enter.
Once you decide to exit the circle, switch from left to right signal to indicate your intention to drivers waiting, that they can begin their entrance into the circle as they see you start to veer right. As well, your signals also let the driver behind you know where you are going. Since the circles are designed for slow speed, you have adequate time to signal all your intentions, thus letting every other driver know where you are going. When you are in the circle, watch approaching drivers about the enter ahead of you to determine if they see you and are yielding.
For the many people who do not signal whatsoever at roundabouts, it is frustrating to wait and see where they are going.
Driving Instructor (retired)