Here are aerial shots of all the roundabouts in Assen, all of which include cycle facilities. The images are taken from Google Maps. If you're interested, you can look for them, with their context, yourself.
|Roundabout on ring road. The underpass from South West to North East, nearly as wide as a road, provides direct cycle access to the city centre without having to stop (previously seen here). The cycle path is four metres wide, and next to it (barely visible in the picture) is a two metre pedestrian path. The North-South road is the ring road around Assen. Cyclists are not permitted to use any of the roads in the picture, so not having access to them is not a problem. Going through the underpass is in any case quicker than going around the roundabout. See what the experience is like for cyclists at this roundabout in this video. No crashes of any kind in five years, no injuries.|
|North of the city, this roundabout connects the motorway junction with the direct road North. High quality cycle paths go in all directions except onto the motorway. The paths heading North are unbroken for 5.5 km to and through the next village. They have an especially smooth concrete surface which has priority over all side roads and are well separated from the road to and through the next village. At this point there is no pedestrian path as there is little pedestrian traffic. The few people who make this longer walk use the cycle-path. Over five years, there was one incident here where a driver left the road and hit a piece of street furniture. No injuries.|
|In a new and as yet undeveloped industrial area, the cycle (red) and pedestrian (grey) paths don't provide access to the road to the North East - towards the motorway junction. Zero incidents.|
|The ring road is intersected by direct cycle route to the centre of the city from outlying villages. No recorded incidents here in five years.|
|Busy road to the East within a residential area. Cycle paths go in all directions around this roundabout, merging with 30 km/h roads to the North and South. Four crashes here in five years, one motorist injured. No cyclists involved in any crash.|
|Industrial area. Cycle path approaches from the North, access road continues safe access to the South. To the East is a motorway junction. No cycle access there. No incidents here of any type.|
|A junction on the ring road by which cars bypass the older direct route to Assen. No need for bikes to use the road West to East here as this is merely a bypass of the older and more direct route a little further North which remains open to bikes but is no longer usable by car. This roundabout has an extra lane which allows drivers to go from west to east without giving them the option to turn left. This combined with the requirement that cyclists cross two lanes at once makes it more difficult for cyclists to use safely. Happily it is not quite so bad as a turbo roundabout, and it is in any case not a heavily used junction by bike. Three crashes here in five years, none involving injury to drivers, none involving a cyclist.|
|Junction inside residential area. Note that large "30 km/h" signs on the residential streets s are visible, as are cycle paths in all directions. 30 km/h roads sometimes have separate cycle paths. No incidents here in five years.|
|In a new housing development, cyclists mostly travel South to North-West or North-East. An extra access is provided for people who live on the West. One crash between cars here in five years. No injuries. No cyclists involved.|
|An asymmetrical arrangement. The main route is North to East, so the cycle paths are not the same on the west wide. One crash between cars here in five years. No injuries. No cyclists involved.|
|In a new residential area, the road to the south west has a 30 km/h speed limit and is relatively lightly used. No crashes here in five years.|
|Residential area, cyclists can more easily access homes than motorists can. No crashes here in five years.|
|A direct route to the new suburb on the west of Assen is provided here. The road to the North East is access to a natural gas extraction facility and does not need cycle access. No crashes here in five years.|
|This area to the West is as yet mostly undeveloped. However, the roundabout has been built in preparation for cycle traffic which may appear in the future. No crashes here in five years.|
|Between residential areas on the West and the centre of the city, this roundabout is one of the busiest in Assen for cyclists, provides good access by bicycle and has proven to be very safe. Four "fender benders" here where motorists have shunted each other. No injuries, no cyclists involved. Another blog post expands on this this very safe roundabout design.|
|Update 2014: I forgot this one too. Near a large bus-stop with much cycle-parking, it serves many buses as well as many bikes. It's on the main route North from Assen, but as the majority of the traffic travels in a tunnel this doesn't affect the roundabout. This is the site of three collisions in five years, none causing injury and none involving a cyclist.|
Finally, just because someone will probably spot it on a map, there's also this "roundabout" with no obvious cycle facilities. However, actually it's not really a roundabout in the same sense. This is a residential area without through routes for motor vehicles:
|This is a small "roundabout" in a residential area. All streets have a 30 km/h speed limit, and are arranged so as not to be through roads for drivers. However, it's not equivalent to the others. These roads are not for through-traffic. This is an example of segregation of modes without cyclepaths. The same rules do not apply. Take a look on streetview. This roundabout had no incidents of any kind in five years.|
To design a Dutch inspired roundabout adopting only the geometry but without cycle paths, as I've seen proposed in the UK, is to very fundamentally miss the point. This is just one of many ways in which what has been achieved in the Netherlands has been misinterpreted elsewhere.
For cycling provision to be able to influence peoples journey choices and encourage a high modal share for cycling, it must be universal and consistent. This way you get adequate subjective safety so that people will cycle. It is never too late to start building such a network, and it won't take as long you think.
Think these designs won't fit your town ?
Roundabouts are only safe for cyclists with relatively low traffic flows and relatively good sight lines.
If you have roundabouts in locations where these roundabout designs wouldn't fit, it's quite likely that those junctions wouldn't be roundabouts at all in the Netherlands. Please read a companion blog post which shows every traffic light junction in Assen, many of which are of the the simultaneous green design - the safest traffic light design for cyclists. This may be a more appropriate design for your location, as could be an attempt to unravel routes.
In Assen, cyclists do not have priority where cycle-paths cross roads approaching roundabouts. This has been shown to be safer than the design used in some other parts of the Netherlands where cycle-paths have priority over the road crossing. Whether or not to give cyclists priority has long been a contentious subject because of this balance between safety and convenience. There is a big contrast between the safest designs and the least safe.
Since this blog post was written, Assen has built one new roundabout in a residential area which is very similar to the tenth example above complete with similar cycling infrastructure and begun construction of a turbo-roundabout. Turbo roundabouts are a special kind of roundabout designed to deal with high volume of motor vehicles. They are not intended to be used by cyclists. Assen's new turbo roundabout is being built to cater for a new motorway junction well away from any cycle routes. It is not easy even to approach by bike.