Shame on the engineer who feels limited space precludes a roundabout at Lerwick and Ryan.
May I give a historical example of the simplicity of the tried and tested safety of this pretty ancient highway feature?
The Roman Colosseum, a multi-lane roundabout, facilitating more traffic than Ryan at Lerwick will ever see, working well for over 2000 years.
Piccadilly Circus and Trafalgar Square in London, and thousands of mini, and larger roundabouts throughout U.K., all facilitating a traffic overload, with hundreds of years of operational history.
It's not the size of the roundabout that's important, but rather the principles and rules relevant to negotiating it. Just think, no lights, and no electricity.
Power cut, who cares? Little maintenance, and it can be attractive.
Sure looks better than a pile of scrap metal where two or more cars play "Let's beat the red light game."
Environmentally, it's a winner. Less braking and accelerating, less carbon emissions, less maintenance, and cheaper by far than lights, etc.
Remember, the rate of traffic flow from all points of the compass at a roundabout is vastly superior to, and safer than the standard traffic lights setup. Pedestrians can cross on flashing light crossings set back from the roundabout entrance.
Time to move into the 21st century traffic mode, don't you think?