The best roundabout design for cyclists. The safest Dutch design described and an explanation of why this is the most suitable for adoption elsewhere

Roundabouts are often disliked by cyclists because using them by bicycle can be fraught with danger. When riding on a roundabout, you rely upon drivers seeing you on your bike. There is a tendency for motorists to look right through cyclists while looking for other motor vehicles, hence the frequency of "SMIDSY" incidents. However none of this has to be the case. The best Dutch roundabout designs do not cause significant danger for cyclists. But note that not all Dutch roundabouts are created equal. There are big differences in the safety of different designs of roundabout used in the Netherlands, and not all advice from this country emphasizes the safest design.

This blog post is mainly about this roundabout. It's an urban roundabout used by a large volume of traffic including pedestrians, cyclists, cars. buses and trucks. It's interesting because of its very good safety record - just four crashes in five years, all minor car-car crashes, none of which involved a pedestrian or cyclist and none of which caused an injury to anyone.

There is a common misconception held in other countries that Dutch roundabouts are safe for cycling due to their geometry, but actually the roundabouts of Assen, just as other Dutch cities, vary enormously in design. The geometry of Dutch roundabouts is not the common factor which makes them safe. What makes them safe is removing cyclists from harm's way and the safety of different Dutch designs comes down very much to how well they keep cyclists away from potential injury.

In the Netherlands it is not expected that cyclists should be mixed with motorized traffic on roundabouts. There is always a cycle-path or lane of some form. While cycle-lanes around roundabouts are not generally thought to work well. there are two opposing views on how these cycle-paths should be designed. One view holds that cyclists should have priority across each road leading to the roundabout, the other holds that it is dangerous for cyclists to have this priority. The current recommendation¹ is for roundabouts within towns to be the "cyclists priority" design while roundabouts outside towns give priority to motor vehicles, and many towns in the Netherlands have adopted these recommendations. However, not all towns have done this and Assen is one of the hold-outs.

Adverse camber on the roundabout
itself encourages slow speeds, which
improves safety for all users. Longer
vehicles have to use the red surfaced
raised area which further increases
the camber.

The roundabouts in Assen have a particularly good safety record even by comparison with other Dutch roundabouts in other Dutch cities. During the five year period between 2007 and 2012, there were just two cyclist injuries at all the 21 roundabouts combined. The impressive safety of Assen's roundabouts is in part due to the city having ignored the recommendations made in the CROW manual and having retained motorist priority on each of the crossings. This may sound as if it makes cycling less convenient, but we have not found this to be a significant problem. It's rare that a cyclist must put their foot down and stop. It is more often the case that cyclists adjust their speed and merge through any traffic which is crossing the roundabout. That is actually much the same as a cyclist would do on approach to any other roundabout design. In reality you must give way at some point or another on entering any design of roundabout. All that changes between these two designs is at which point you must give way.

The design of Assen's roundabouts results in crossings of roads always being at 90 degrees and the 90 degree crossing point being where cyclists must give way. This makes it easier for both drivers and cyclists to see what is happening in all directions of interest. This roundabout design also makes sight-lines longer which gives more time to react, more time to adjust speed so that it's almost always possible to cross without stopping. Both of these result in safety advantages over the other Dutch roundabout design which has an annular ring.

With this design, a significantly higher degree of safety is achieved in exchange for perhaps a very slight decrease in convenience. But the decrease in convenience is really not large as people often fear, especially when we take into account that cyclists can cross safely in both directions around roundabouts where the crossings are at 90 degrees. This saves time because it's possible to take a short-cut across the junction and reduces exposure to risk as we need cross only one arm of the roundabout to make a left turn instead of more if we had to ride all the way around the roundabout to make a left turn.

Please do watch the video as it demonstrates clearly how efficient and safe this design is. Note how at the start of the video it is demonstrated that it is possible to travel across this roundabout by bicycle without adjusting one's speed at all. This would not be the case with a "cyclist priority" roundabout or by cycling on road as in both cases a reduction of speed would have been necessary at the point of reaching the roundabout.

The video shows one of the busiest roundabouts for cyclists in Assen and demonstrates why it is both safe and convenient for cycling. Only four collisions of any type were recorded here in five years, and they were all of the "fender bender" variety, where one driver shunted another at low speed on the way on or off of the roundabout. No cyclists or pedestrians were involved in any way in any of these minor collisions and there were no injuries to the drivers either:

This is even more important for other nations

DO NOT COPY THIS EXAMPLE
This photo has featured on many blogs
but they unfortunately picked a bad
example. This is the annular ring design
with cycle priority at the crossings
which is seven times more dangerous
than the design which I recommend.
This type of roundabouts causes between
 52 and 73 extra injuries per year in the
Netherlands. Copy the safe design
which is illustrated elsewhere in
this blog post.

It has been known within the Netherlands for many years that roundabouts which have annular ring cycle-paths and on which cyclists have priority over each arm are less safe than those of the design which we have in Assen (nationally, SWOV originally estimated an extra "52-73 in-patients a year" due to the dangerous design, there are now three times as many of them so it believed that an additional 100 to 150 cyclists a year are now hospitalized because of the poor "priority" design). The decision to favour the cycle priority design was taken in an attempt to increase cycling convenience at the cost of safety.

The safety cost of choosing cycle priority will almost certainly be greater in other nations than it is here in the Netherlands. Dutch drivers are more familiar with bicycles than drivers of other nations and there is also a good chance here that bicycles will dominate any particular roundabout, making them difficult to ignore or overlook. Neither of these factors can be relied upon in other countries. For that reason I suggest that the safer design presented here should be the only roundabout design for cyclists adopted by other nations.

2018 update: The number of roundabouts in the Netherlands has doubled since the report was written. Because the dangerous priority design was widely adopted there are now 100-150 injuries requiring in-patient treatment at hospital and concerns about the rising number of casualties due to this dangerous design. Please read more about this in a new blog post about this subject. The priority design has proven not to be beneficial to cyclists in this country and it won't be beneficial in your country either.

How much safer is this roundabout design ?

Section from the English language summary of the report on
roundabout safety. The with-priority design is barely safer
than an un-signalled crossing while the safe design shown
recommended here is very much safer.

People keep asking me how much safer this roundabout design is than the "priority" design and if there are any figures to prove this. The document linked two paragraphs ago (there's an English language summary on page 5) gives the answer quite clearly. The annular ring design with cyclist priority is 11% safer for cyclists than an un-signalled junction while the same annular ring design without cyclist priority is 87% safer for cyclists. i.e. The expected injury rate due to cyclist priority alone, on the annular ring design, is nearly seven times higher with cyclist priority ( (1-0.11) / (1-0.87) ~= 6.85).

The roundabout design recommended here is, at the very least, seven times safer than the alternative Dutch design

However the design which I recommend is specifically designed in order to improve sight lines and also to lower both cyclist and driver speeds at the point of conflict (rather than slowing cyclists only at the point of joining the ring). We can therefore reasonably expect that this design will be associated with better injury rates. Combining both the improved sight lines and the better result for priority should result in a much better than 7x improvement in safety. The difference in outcomes suggests that estimating that the improved layout results in at least a 2 or 3 times safety improvement is quite conservative, leading to the safe design described above being at least 20 times safer than the unsafe design with cyclist priority.

There is no need to guess as we do have figures. We see a very obvious result in real life statistics for roundabouts. Injuries are rare at the design which I recommend, while they are remarkably common where the annular ring design is combined with priority for cyclists. Remember that these figures come from real injury statistics in the Netherlands, with Dutch drivers who are familiar with cyclists. There is likely to be a much greater difference in safety should the same designs be tried in other countries where drivers are less familiar with and less respectful of cyclists.

Note that the 11% improvement in safety for the priority roundabout design over an un-signalled junction for Dutch cyclists with Dutch drivers is a very small figure. You shouldn't necessarily expect this to apply for cyclists in other countries from the same design. It may even be that the situation is worse than an un-signalled junction in other countries. But the very strong result from the safe roundabout design is likely to still have some significance in other countries.

Safe vs. "convenient" ?
The comparison between these two roundabout designs has in some places taken the form of an argument about safety vs. convenience. There is an attempt to paint the added convenience of one type of roundabout as a certainty while the safety advantage of the other is played down as being "very slight". In fact, it is proven that the safer design (as recommended in this blog post) is seven times safer for cyclists than the other design, while the relative convenience of the designs is open to debate. I find that the safer design is also very convenient. If you doubt this, please watch the first 80 seconds of a video in which I demonstrate how I regularly cross the roundabout illustrated above in both directions without stopping.

While the design on the left is often referred to as a "cyclist priority" roundabout, cyclists actually have to give way on both types of roundabout. The main difference is that the point where you give way is not coincident with the point of conflict on the design on the left while it is coincident with the design on the right. This means that the cyclists at most have to slow down and speed back up once with the design on the right and can do so while assuring their own safety. Note that drivers have to give way at the same point on both roundabouts, and that giving way to cyclists in the Netherlands is significant because there are often more cyclists than drivers using junctions in this country. The case shown above is a best case so far as the "priority" roundabout is concerned. Sometimes they are very much less convenient as can be seen in a video.

A much smaller example following the
safe design princples. A busy
roundabout serving a high-rise car
park which does not injure cyclists.

The principles of design are important, not this exact size and design
I chose this particular example for the video because it's very clear what is going on. It's large and it's relatively green for an urban location, but this makes makes it easy to demonstrate in a video how the roundabout works. The principles which make it safe (90 degree crossings, good sight lines, plenty of time to make decisions, obvious priority, some journeys made without joining the roundabout at all) can be, and often are, applied on a smaller scale.

The small size of the island at this
roundabout can be seen in this photo
from a recent study tour.

The smaller example illustrated here applies all the same principles as the main example above but on a much smaller scale. It could in fact be made smaller yet. There have been no cyclists or pedestrians involved in a crash here. Only two minor fender-benders between motorists are recorded, neither causing an injury.

Summary of points which make the safe roundabout safe

1. 90 degree crossings between cyclists and drivers to improve sight-lines of both.
2. Not relying upon drivers to take decisions which maintain the safety of cyclists or give way on behalf of cyclists but giving that control to cyclists themselves.
3. Adverse camber for cars going around the roundabout to slow cars down.
4. Refuges between streams of motor traffic which are wide enough to accommodate a whole bicycle.
5. Bidirectional cycle-paths because they allow cyclists to cross fewer streams of traffic - crossings are where the dangerous interactions occur.
6. Right turns take place with no interaction at all between cyclists and motor vehicles.
7. The layout makes it very obvious to everyone what they should do.

Not every junction should be a roundabout
CROW suggest that roundabouts are appropriate only on junctions with up to 500-1500 motor vehicles per hour on the busiest arm of the roundabout. Note that that is a peak not an average. It doesn't imply safety with 12000-36000 motor vehicles per day, but that the peak hour should be 500-1500 max. Most roundabouts in the Netherlands have flows considerably lower than the maximum allowed. Where more vehicles must be catered for, they suggest not having cyclists going around roundabouts at all, but using other junction types such as traffic light junctions or cycle unfriendly multi-lane roundabouts which then require grade separation (see next section).

Too little space ? Too much traffic ?
Think about Simultaneous Green, the
other really good junction design.

If you are looking to copy these principles but there is not space for a safe roundabout in your location then perhaps a roundabout is not the correct solution for you. There are other possibilities. Simultaneous Green traffic lights can work even for very small junctions, but in the Netherlands note that many traffic light junctions in small streets have been removed altogether, along with the motor traffic which they used to serve. By doing this, a safe situation can be achieved almost anywhere.

For a complete picture of all the complex junctions in Assen, see previous blog posts about every roundabout in Assen and every traffic light junction in Assen.

CROW suggest that a peak (rush hour) hourly intensive above 1500 motor vehicles always requires a tunnel, a bridge or a traffic light junction to be built instead of a roundabout. These solutions are also preferred at lower traffic levels (1200-1750 or >1000) in different situations.

Don't forget about unravelling
Another factor which leads to the safety and convenience of Assen's roundabouts is that they are largely avoided by cyclists. Bicycle routes here are unravelled from driving routes. Many of the 21 roundabouts feature only infrequently on cyclists' journeys or do not feature at all.

CROW suggest that higher traffic levels should result in cyclists being grade separated. Here's an example of just that. This roundabout on the ring-road in Assen has a perfect safety record for cyclists and probably always will have. Why ? Because there's absolutely no need at all for any cyclist to ever interact with motor vehicles on this roundabout:

This roundabout is even safer for cyclists, but it cheats by not really being a roundabout for cyclists at all. Grade separation should be the norm where cycle routes cross busy ring-roads which pose a safety risk.

Other real-life Dutch roundabout designs
Below you'll find examples of other roundabout designs used elsewhere in the Netherlands. Most of these examples have a less convincing safety record than the examples illustrated above. They're shown along with their safety records in order to demonstrate what does not work well and should not be emulated elsewhere.

Shared Space "squareabouts"

Drachten is a smaller town than Assen a few kilometres to our west.

There has been considerable international attention drawn to a Shared Space "squareabout" in that town. Much has been written about this being a safe design. However, if we ignore the hype and look at the statistics then we find a very different story:

Laweiplein Shared Space "squareabout" in Dracthen. There have been ten crashes here, injuring three cyclists and one moped rider. This single Shared Space junction is more dangerous for cyclists than all of Assen's 21 roundabouts and all of Assen's Simultaneous Green traffic light junctions added together. 

Turbo Roundabouts

Turbo-roundabout under construction
by a motorway junction south of
Assen. Absolutely no bikes near here.

There has been an unfortunate mis-understanding in the UK over turbo-roundabouts with at least one council seriously trying to implement a turbo-roundabout for cyclists.

This is a huge mistake. Turbo roundabouts are designed to maximize flow of motor vehicles. They're a good design for motorway junctions and similar places where there are many motor vehicles and absolutely no cyclists or pedestrians.

Note that Turbo roundabouts are also recognized to be dangerous for motorcyclists. Motorcycling groups have complained in the Netherlands.

Groningen

Dangerous roundabout in Groningen.
See the first picture below.

Groningen, which won the Fietsstad competition in 2002, is famous for having the highest cycling modal share in the world. This is the result of policies starting in the 1970s and it is also contributed to by the extremely high student population.

Unfortunately, the city has not progressed so well since 2002 as it did in the years before it was awarded a prize. Local campaigners have been vocal about this. Groningen's infrastructure is variable in quality but problems caused by this are to some extent masked by the high level of student cycling.

One of the most dangerous roundabouts in Groningen has been featured in previous blog post. We've used it for some time on study tours as a contrast with good roundabout design. To demonstrate what not to do:

This busy Groningen roundabout is the scene of 36 incidents in five years resulting in injuries to two pedestrians, three cyclists and two moped riders. This is not good design.

All of the roundabouts within Groningen are of the annular ring design and all give priority to cyclists. Unfortunately, none of them have an especially good safety record:

A suburban roundabout, relatively low traffic but with 18 crashes including six cyclist injuries.

A few metres away, this roundabout in the same suburb is the scene of 13 crashes including two cyclist injuries

This roundabout has different geometry to the other three and better sight lines. In particular, there is a wide verge the length of a car between the roundabout and the cycle-lane. This gives a space in which drivers can stop between the road and the roundabout in a similar manner to how it is possible for them to do so in the example above from Assen. However this detail but that hasn't prevented there being 8 crashes here. One cyclist and one moped rider were injured. I write about an experience at this roundabout below.

Just outside Groningen to the South we find a roundabout more similar to the design used in Assen, with better sight lines and where motorists have priority. At this roundabout there has been just one collision between a motorbike and a bicycle which unfortunately caused an injury. The vertical grey line in the roundabout is a sculpture.

Zwolle
Zwolle is the current holder of the "Fietsstad" award, an occasional award presented to the Dutch city which is considered to be trying hardest to grow cycling.

Zwolle's "Bicycle Roundabout", built last year, has similar
appearance to known unsafe designs and as yet no safety
record. I'm not praising it unless it turns out to be safer than
it looks.Update: See below. Cyclists were injured here within
weeks of opening.

Zwolle achieved an amazing amount of positive press last year for an unusual "bicycle roundabout" (fietsrotonde) junction design. This unproven design was even used as part of the marketing campaign for the city's Fietsstad competition entry. The "bicycle roundabout" works as a roundabout for cyclists while for drivers it is a straight through road. The kerbs are narrow, sight lines are short and crossings are not at 90 degrees. Press releases about this junction and other sources have made claims made about its safety but in my view praise should wait until there is a proven record of safety. That is why I did not write about this junction before now. We must first wait to find out what the long term safety outcome is and until then treat the new design with caution. This is especially not something for other nations to try to emulate.

It is claimed that Zwolle drivers' familiarity with existing roundabouts will lead to the bicycle roundabout being safe. I see this as spurious as while Zwolle doesn't have many other roundabouts those that it does have actually do not have a good safety record at all by Dutch standards. There are some examples below.

Update: I've discovered that the Bicycle Roundabout in Zwolle has in fact already claimed victims. It opened at the end of August 2013, the first cyclist injury was in September and another cyclist was injured in November. Zwolle's Bicycle Roundabout has therefore claimed as many victims in three months as all twenty-one of Assen's roundabouts caused in five years. Even relative to the previous supposedly unsafe situation this doesn't seem very impressive. According to the Ongelluken Kaart, there was only one injury in this location in the five years between 2007 and 2012. Also read how the Bicycle Roundabout was advertised in advance as part of the effort to win the cycling city (fietsstad) award.

Further update: Thinking more about this, it seems that the whole idea of the "bicycle roundabout" is flawed. Compared with the unsignalled junction which existed before it was built, a normal roundabout of the type used in Zwolle might be expected to achieve a 75% reduction in injuries to motor vehicle occupants but just an 11% reduction in injuries to cyclists. However, the bicycle roundabout as built doesn't meet good guidelines even for that type of roundabout. Sight lines are very short. What's more, given that part of the reason for enhanced safety for cyclists at a normal roundabout is a result of drivers being able to make a choice not to exit the roundabout at a point where there is conflict with cyclists, and given that in this instance that choice has been removed and drivers are forced to exit in conflict with cyclists, there seems no good reason at all for anyone ever to have assumed that this design would in fact be safer. Therefore the elevated injury rate due to the bicycle roundabout should be no surprise to anyone.

Update 2018: In a reader's poll in a local newspaper, the Fietsrotonde was chosen by cyclists of Zwolle as what they believed to be the most dangerous place in the city for cycling. Perhaps more worryingly, even though it had been improved since I wrote this piece, the first roundabout featured below is still of the priority design the the council now admits that this is the most dangerous place in the city for cyclists. If Zwolle had instead converted the roundabout into the the safe design which I recommend then this would not have happened.

Zwolle Urban roundabout with priority for bikes. 15 crashes here including four cyclist injuries
Update 2018: Zwolle completely rebuilt this roundabout, but instead of choosing the safe design featured at the top of this blog post they changed to a different unsafe design so this continues as the most dangerous location in Zwolle for cyclists.

Zwolle Suburban roundabout with priority for bikes. 25 crashes here including six cyclist injuries.

Another of Zwolle's cyclist priority roundabouts. 22 crashes here including two cyclist injuries

Eindhoven
Eindhoven is a city which we used to visit quite often as for a while we thought we might settle in that area. It's a larger city with few roundabouts. Much as we've seen elsewhere, the roundabouts which have priority for cycles have injured cyclists while those which keep cyclists well away from motor traffic have not:

Eindhoven roundabout with priority for cyclists. Ten crashes in total, four cyclist injuries

This junction resembles the design used in Assen, but it is truly enormous in scale. It gives cyclists priority. The crossings are far from corners in the cycle-paths and far from the roundabout, which itself has a much larger radius and will support higher speeds. Perhaps it is the resultant speeds of both cyclists and motorists alike at the crossings which adds danger here. Two cyclists have been injured here in five years.

On the other hand, this enormous multi-laned roundabout in Eindhoven has caused no cyclist injuries at all. Why ? Cyclists are completely grade separated from motorists. Therefore, despite the huge size of this road junction, it is both safe and convenient for cyclists to use.

This is the Floraplein in Eindhoven. A turbo-roundabout. Turbo-roundabouts are designed for maximum flow of motor vehicles and should never be built where there are cyclists, but this one was. There has been much local opposition to this roundabout including a protest video showing the problems that it causes. I featured a video of this roundabout in a blog post from 2012 in which I warned against campaigners mistakenly calling for this infrastructure for cyclists. Needless to say, between 2007 and 2012 there were multiple collisions here, several involving cyclists and one cyclist had to go hospital as a result.

Valkenswaard

Valkenswaard roundabout visited in 2006. Not a safe design.
See below for statistics.

Valkenswaard is a village outside Eindhoven which we visited on the 2006 study tour. At that time I was myself impressed by the idea of cyclists having priority on roundabouts. Of course everyone is attracted to the idea of priority, but when we find out that the statistics show this design to unsafe, resulting in people having been sent to hospital because of injuries which occurred here we should of course think twice about the value of such a design.

In 2006 our group spent some time looking at and riding around this one roundabout in particular as cyclists had priority there. That's why I've included this village in these examples.

We now know that this wasn't really a good example to take notice of as even though this is just a small village and there is little traffic here, this roundabout is the site of quite a number of cyclist injuries. Compare this photo with the new Zwolle bicycle roundabout (above). The obvious similarity is part of why I am skeptical of that new design.

A roundabout which the 2006 study tour group were somewhat enamoured by. It's in a relatively low traffic situation suburban but there have been seven incidents here including three cyclist injuries. i.e. even this single roundabout in a small village is more dangerous for cyclists than all of Assen's 21 roundabouts put together. This is because the annular ring design is more dangerous for cyclists even when traffic volumes and speeds are low.

Outside Valkenswaard, a rural roundabout without priority for bikes. Just one crash, no injuries, no involvement of cyclists.

Outside Valkenswaard, a busier roundabout without priority for bikes. No cyclists involved in crashes here.

Enschede
One of the most influential pieces of research in the Netherlands which convinced many people that cyclists having priority on roundabouts was a good idea was carried out in Enschede in 1991 and appeared in a report from 1992. Unfortunately, as is admitted in the conclusion of that report, their positive result was based upon research which involved just a few hours of observation. Based on their short observations, they estimated that the change in priority would have a very small effect on safety. We've now had many years to see what really happened (these roundabouts have proven themselves to be seven times more dangerous as detailed above). This is the very same roundabout as was used for the 1992 research:

The roundabout between the Knalhutteweg and Broekheunering in Enschede used for the investigation into cyclist safety with priority on roundabouts. There were 23 collisions in five years here, two of which injured cyclists, while two more injured a moped rider and a pedestrian. For cyclists, this roundabout, used so often to "prove" the safety for cyclist priority, as shown itself to be as dangerous as all 21 roundabouts in Assen combined.

A few hundred metres to the North, this is the roundabout between the Knalhutteweg and Vlierstraat. At this location, there have been 15 crashes and no fewer than five cyclists injured in five years.

Closer to the centre of the city, this roundabout has been the site of 38 crashes. In this case only one cyclist was injured, but two car occupants were also injured in one crash.

Another Enschede roundabout. This example has had 20 crashes over 5 years. Six cyclists were injured here.

Looking for relatively good examples from Enschede, I found this "roundabout", the location of just five minor crashes and no injuries over five years. Suspicious of the exposed ground on the left of the picture, I looked at Streetview which revealed that this wasn't a roundabout at all during the time when the statistics were counted. It will be interesting to see what happens here in the future. Will converting this previously very safe junction into a roundabout lead to a safety improvement ?

Fietsberaad still have the Enschede roundabout as a good example on their website. I disagree. The four roundabouts in Enschede that I feature above have wounded 14 cyclists in five years. That's seven times so many injuries as all 21 roundabouts in Assen combined. This gives each of the Enschede roundabouts which I looked at a safety record on average 36 times worse than an average roundabout in Assen.

Purmerend
A webcam set up to observe a roundabout in Purmerend has unfortunately led to people from the English speaking world thinking that they're observing a safe example from which to copy. In fact, the Purmerend roundabout has caused many injuries to cyclists:

The roundabout in Purmerend near the software company "Archie CRM" has caused many crashes. It is recorded that twelve crashes occurred and that those crashes injured six cyclists such that they required hospitalization in just the two years of 2008 and 2009. There's a lack of data for other years but the design of this junction has not changed.

's-Hertogenbosch
Den Bosch is another of the cities where the more dangerous design is preferred and another where the most dangerous junctions for cyclists are roundabouts.

The most dangerous junction for cyclists in 's-Hertongenbosch is this roundabout which caused hospitalization injuries to five cyclists and three moped riders in the three years between 2008 and 2010. These are not good examples of roundabouts to copy from.

Update: Where the danger comes from
It seems I need to explain more about why the roundabouts with priority dangerous, regardless of their layout. It's not just that the annular design of cycle-paths makes visible difficult but also that it expects perfect behaviour from drivers.

Giving cyclists "priority" sounds positive, but what actually happens with the priority design of roundabout design is that cyclists are stripped of control. The design requires that cyclists should ride out in front of motor vehicles and hope for the best. On this type of junction design, cyclists are used as mobile traffic calming devices. The cyclist priority design requires that drivers who don't know the rules, are tired, talking on the telephone, changing channel on their radios, arguing with other people in their cars, who can't see out of misted windows, who are impatient and don't want to stop for a cyclist (especially important in other nations where there is more anti-cycling sentiment than here) or who are simply not skilled at driving must never make a mistake because the safety of cyclists depends almost entirely on the driver and not on the cyclist themselves.

My view is that cyclists make better decisions about their own safety than drivers can make for them. This is supported by the comparative injury statistics above for roundabouts which give cyclists control over their own safety vs. those which give them "priority" or supposedly let them share equally with drivers.

An incident from earlier this week may help to explain. Judy and I rode nearly 80 km planning a cycling holiday route and we passed seven roundabouts on our way. Five of them were of the safe design and were crossed without stopping. One was of the safe design and we had to wait about ten seconds.

I'm the red arrow, the learner is the blue
arrow, the woman from the right is the
green arrow. There's too much to look
out for here. That's the problem with
this design. Good design doesn't rely
upon bright yellow warning signs to
try to enforce priority.

Just one of the roundabouts on our route was of the "priority" design. This just happened to be the same roundabout as I had already written about above as one of the safest in Groningen (it has better sight-lines than many and there have been 'only' eight crashes). On this roundabout, we needed to go straight on (second exit) so joined the annular cycle-path. At the same time as I joined the cycle-path around the roundabout, a learner driver who had been travelling parallel with me with his right indicator flashing joined the roundabout. I had to trust that the learner had seen me, that he understood the priority rules and that he was going to stop. He did, but he did so a little late and his front bumper was uncomfortably near the cycle-lane. My attention was distracted by the learner approaching from my left and I wasn't looking out for the driver coming from my right who had also not been paying attention and who stopped her car very sharply half way across the cycle lane in front of me. I had to swerve to avoid her car.

There was no crash and both these drivers stopped, but they both did so too late. With slightly different timing, for instance if either the drivers or myself had been going slightly faster or slightly slower, it could have worked out differently. This is not fail safe design. SWOV point out that "drivers have to make (too) many observations in a brief time span, resulting in them noticing cyclists too late" and that is precisely what seems to happen at cyclist priority roundabouts.

That is but one anecdotal illustration of the type of incident which simply doesn't happen with the roundabout design which I prefer, and which has been proven to be safer. We have known for more than a hundred years that we cannot rely upon perfect behaviour from drivers but this is what the priority roundabout design does rely upon. Instead of cyclists being able to take safety into their own hands, their control is taken away and their safety is assured only by drivers behaving perfectly. The roundabout priority design flies in the face of the sustainable safety principles which otherwise keep Dutch roads safe.

Even very young cyclists can ride
safely across this junction in Assen
where cyclists have priority over
drtivers. Perfect safety record here.

This blog post is about roundabouts
Don't confuse the concerns about safety at roundabouts with priority with other locations and situations. It is never helpful to try to apply a one size solution to all problems.

Concerns about roundabout priority do not apply in other situations. There are many thousands of safely designed junctions between roads and cycle-paths, here in Assen and elsewhere in the Netherlands, where cyclists have priority. Where this is the right solution. i.e. junction design is good, sight lines are long and traffic volumes and speed are not overly high, these junctions have very good, often perfect, safety records.

It is the existence of such infrastructure which makes cycling both convenient and safe in the Netherlands.

Find out more
Book a study tour to find out more about good junction design and other factors which lead to the high rate of cycling and good safety record for cyclists in the Netherlands.

¹ The CROW Design Manual for Bicycle Traffic states that "On roundabouts inside built-up areas, it is recommended that cyclists on separate paths continue to have right of way. After all, this corresponds with a cyclist-friendly policy". I disagree that this is the best way to design roundabouts, especially when considering road conditions and existing road use conventions in other nations. The CROW manual also refers to low traffic (less than 6000 pcu/day) roundabouts as not requiring cycling infrastructure. In reality, roundabouts in the Netherlands without cycling infrastructure are roughly as common as unicorns. I can't remember seeing a single example.

The Dutch Institute for Road Safety Research, SWOV, are also skeptical about roundabouts which give priority to cyclists. You can read more from them here: http://www.swov.nl/rapport/Factsheets/UK/FS_Roundabouts.pdf, http://www.swov.nl/rapport/R-2004-14.pdf


Part way through writing this blog post, several people drew my attention to the new Austroads document about cycle-lanes around roundabouts. They came to a correct conclusion that encouraging people to cycle around the edge of roundabouts is a bad idea, but their suggested fix (sharrows to encourage cyclists to "take the lane") is not adequate. The design presented above works well for all abilities of cyclist.

All the aerial photographs with flags showing collisions on this page come from the excellent ongelukken kaart. This shows all crashes in the Netherlands between 2007 and 2012. Blue flags indicates crashes and the number is how crashes have occured at that location. Yellow flagss indicate that at least one injury occured, red indicates at least one death

This post originally referred to 19 roundabouts in Assen which I had written about in a previous blog post. That has now been updated to cover an additional two roundabouts which I overlooked. These had also not injured cyclists.

Update 2018: A study tour participant made this drone video of the roundabout at the top of the article: