Sometimes you have to be careful what you wish for. If you're not absolutely sure what a Turbo Roundabout is (in particularly, a "turbo-roundabout" as might be implemented by TfL) and not absolutely sure that it is what you want, then don't ask for one.
This video from the Fietsberaad shows a "Semi"-Turbo Roundabout in Hilversum. It initially appears to work quite well in the video designed to promote the idea, but this is merely a "semi-turbo" roundabout and in many ways actually more closely resembles normal Dutch roundabouts. I caution to look out for where there are two lanes of motor vehicles which need to be crossed at once by cyclists and pedestrians - a case which is excluded from the video:
The next video came up as a related video on youtube. It's a simulation of a Signalised Turbo Roundabout. It shows how motor-vehicles flow nicely around the roundabout, but there is no consideration of cyclists or pedestrians in the simulation:
Indeed, the whole point of the turbo roundabout is to "improve traffic flow". Turbo-roundabouts were never intended to make things better for cyclists or pedestrians. Cyclists don't much like them. The Fietsersbond (Cyclists' Union) in the Netherlands has complained about unacceptably long crossing delay times for cyclists at Turbo Roundabouts.
As I said before, "be careful what you wish for". Why ? You might end up with something similar to what is in the next video - a real, live, turbo roundabout in Eindhoven videoed by someone who isn't trying to sell the concept. The title is "Floraplein in Eindhoven very dangerous for cyclists":
Note how crossing double exit lanes causes trouble for cyclists.
So what's the alternative ? I didn't have any photos or videos of my own to show here because we don't have turbo roundabouts in this area. In fact I've documented before what all the roundabouts in Assen look like. None are turbo roundabouts, and none cause problems for cyclists.
Some other ideas are pointed to by the website set up by people who are campaigning to improve or replace the Floraplein turbo-roundabout. It includes a link to an interesting presentation about alternatives to turbo-roundabouts written by Peter Kroeze of Ligtermoet and Partners.
When observing from afar it can be difficult to tell what really works from what does not work. We've already seen both shared space and strict liability given far too much credit for the cycling conditions in the Netherlands. Let's not add Turbo Roundabouts to the list of things that are misunderstood.
2013 update - Bedford in the UK building a turbo-roundabout 'for cyclists'
A year after posting this blog post, warning that Turbo Roundabouts, no matter how attractive the name sounded, were never intended to be used by cyclists, a story appeared about the "walking and cycling officer" of Bedford in the UK was proposing to use "Dutch experience to improve cycle safety" by building a turbo roundabout which is actually worse than the example from Eindhoven shown in the video above because there is to be no cycling infrastructure at all.
|In Bedford cyclists will be asked to|
give-way or dismount by these signs,
which have never been used before.
If changing the law, why not do it
for something more worthwhile ?
This recalls an online conversation which I had in 2011 with another Bedfordshire planner. He also wanted to build a "Dutch" roundabout which omitted cycling infrastructure. Various reasons why were given, including the "difficulty" of combining existing on-road cycle-lanes with a Dutch style roundabout which had cycle-paths and his idea that "not all" Dutch roundabouts had separate cycle-paths.
The discussion with the Bedford planner prompted two blog posts from me to illustrate what I had said to him in email. One of these posts demonstrated that there is no problem at all in merging from an on-road cycle-lane onto a properly designed Dutch roundabout. The other post demonstrated how every single roundabout in Assen has separate facilities for cycling because that is the norm in the Netherlands. His concept of a "Dutch" roundabout without separate cycling infrastructure was not similar to real Dutch infrastructure.
Cycling infrastructure is not an optional extra on roundabouts. Where cyclists have to use the same roundabout junction, specific infrastructure must be provided.
It's disappointing that after having had this long conversation and tried to explain to one Bedford planner, another should still have similar misconceptions two years later.
We run cycling infrastructure study tours precisely in order to try to help councils like Bedford to not make such expensive and dangerous mistakes as this one. Planners need to be educated. They need to learn from the best examples and not just guess at what they think best practice might be. We'd be very happy to host a contingent from Bedford if they'd like to see what the Dutch really do so that future "Dutch" innovation in Bedford can be inspired by the real Dutch infrastructure.
Despite my warning and others, this project continued. Further investigation by myself in 2014 revealed that the Turbo Roundabout in Bedford had been signed off by representatives of several British cycle campaigning organisations: Tony Russell (Sustrans), John Franklin (Cycle Nation), Chris Peck (CTC), Ruth Jackson (British Cycling), Ralph Smyth (CfPRE) as well as Robert Semple (Transport for London).
It's extremely disappointing to find that campaigners have such low aspirations as to rubber stamp a proposal which is as dangerous for cyclists as this roundabout design.
Note that the first Bedford planner also pushed through his flawed ideas, building a dangerous design of roundabout branded as "Dutch" in Cambridge.
2013 second update
The British arm of a Dutch based company has proposed turbo roundabouts for the UK which I believe would not be built in the Netherlands. Read a blog post about this, including pictures of real Dutch Turbo Roundabouts.
Also read a blog post which summarises several things which are "Dutch" but which should not serve as inspiration.
2014 update. Assen is building a turbo roundabout
Assen is building a turbo roundabout to serve a motorway junction in the south of the city. As such, it is correctly being built in a place where there are many motor vehicles but where neither pedestrians nor cyclists have any reason to go. Watch a video showing this roundabout and how difficult it is even to get near it by bicycle.