Many cyclists dread roundabouts due to the need to ride fast around them (hoping not to find the road slippery due to spilt diesel), be in the right lane etc. For some people, the need to use a roundabout on the road is good enough reason to cycle along a different route or to avoid cycling altogether.
However, Dutch roundabouts don't cause these problems for cyclists due to being designed a little differently from those in the UK and most of the rest of the world. This design maximises subjective safety of cyclists.
The photo shows a typical Dutch roundabout viewed from the air.
Cyclists are not expected to use the road, but have a segregated cycle path which avoids the roundabout. Note that the central reservation on the road where the cycle path crosses is wide so that a cyclist only has to cross one stream of traffic at a time and can stop part way across the road. This choice of stopping is made by the cyclist, and is not forced when unnecessary by use of barriers.
Also note that the crossing for cyclists is one car length removed from the roundabout itself, meaning that a driver can be stopped waiting to get onto the roundabout without blocking cyclists who are crossing.
On some roundabouts, motorists must give way to cyclists crossing the arms of the roundabout, though that is not shown on this photo nor the accompanying video which shows a similar roundabout in use here in Assen. Despite this lack of priority, from personal experience I find it is rare that one has to do more than slow a little at these locations.
Note how the children ahead of me negotiate the roundabout efficiently, just regulating their speed a little to synchronize with a car coming from the right. I have to slow a little to synchronize with a passing car from the left. It is rare that you have to stop completely.
In addition to the features of the roundabout which are concerned with cyclists, there are also other differences from the British style of roundabout. Note that there is only a single lane of traffic going around the roundabout rather than multiple lanes, and also that the cars entering and leaving the roundabout have to turn quite sharply to do so. This reduces speeds on the roundabout and increases safety.
It is also quite common for cyclists to avoid roundabouts in other ways, such as by using underpasses, so that they're barely aware that the roundabout exists at all.
There are now many posts on this blog about roundabouts. Please click to read them all. The photo comes from a presentation given by Wybe Nauta on the May 2008 Study Tour.