Conventional roundabouts are not considered safe for cyclists. For example in the UK, chapter 8 of Nottinghamshire CC’s Cycling Design Guide 2006 (ref. 1909) says on the subject that
“There is good reason for the cyclists’ fear as they are generally overrepresented in accidents at roundabouts”.
And rule 77 of the UK’s Highway Code says
“You may feel safer walking your cycle round on the pavement or verge”.
This sounds like an admission of defeat by UK highway designers. Fortunately, other countries have come up with design approaches which do not involve road users pushing their vehicle along the road. At one extreme (in terms of cost) there are elevated roundabouts. For example, there is an elevated bicycle roundabout in the Netherlands, the Hovenring, which was opened in 2012 (see wiki here), and an earlier example was opened in Stavanger, Norway in 2010 (see e.g. here).
Less costly alternatives should be possible from alternative designs of at-grade roundabouts. The bicycling blog “A view from the cycle path” recently posted an article about a Dutch roundabout design – at-grade – which the author suggests is the most suitable design for adoption elsewhere. The post has a video of the roundabout in action (the video is also available on youtube here).
“Typical Dutch style roundabouts have a tighter geometry which reduces vehicles speeds and improves visibility. Some also have an orbital cycle lane which allows cyclists to travel around the roundabout separately to other traffic.”
A document available from Germany’s Fahrradportal website says that
“Roundabouts with two lanes may achieve better capacity for motor-vehicle traffic, but also introduce accident risks to cyclists. Similar to the situation at roundabouts with excessive lane width, turbo-roundabouts are not suitable for on-carriageway cycling. Consequently segregated cycle paths around the outside of the roundabout are recommended by the ERA (a reference to Germany’s current guidelines on the design of cycle facilities). The questions whether priority should be given to cycle path users and whether a second level (underpasses for cycling traffic) might be appropriate in some cases are contested, especially in the Netherlands, because so-called turboroundabouts are very rare.
1909 – UK, “Cycling design guide“, Nottinghamshire County Council, 2006
1914 – Germany, “Roundabouts with cycling traffic“, BMVDI, 2013