Roundabout safety for cyclists and why Cambridge's new 'Dutch' roundabout is not what it should have been

This is not the Cambridge roundabout. It's an example of a different
design, the safe roundabout. This design is much more tolerant of
driver mistakes and results in a far lower rate of cyclist injuries.
Please read my blog post about this design and watch the
accompanying video as both of those describe how this
design keeps cyclists safe.

Cambridge in the UK recently opened a "Dutch style" roundabout on Fendon Road to replace another roundabout which had a poor safety record for cyclists in the city. People keep pointing this out to me. I think it's perhaps time for a response.

The design chosen is that which I have consistently recommended against. Why do I recommend against it ? Because it has a poor safety record here in the Netherlands. It has a safety record which is not very different to an uncontrolled crossing or having no cycling facilities at all on a roundabout, which was the situation in Cambridge before this new design was built. I am not convinced that British drivers are better trained or will behave in a safer way on roundabouts than Dutch drivers and therefore I am also not convinced that it will be safer to use this design in the UK than it is here. Dutch drivers have been trained for decades to expect to give way to cyclists under some circumstances and they have also had decades to get used to this type of roundabout, yet it remains unsafe in the Netherlands. Why should we expect this to be different elsewhere ?

Now you might wonder why all my emphasis so far has been on drivers. There's a simple reason. The danger comes from motor vehicles which are faster and heavier than any cyclist. That's why injury rates for cyclists are higher at roundabouts with more cars. Remember always that there is no design of roundabout which is built for cyclists. If it were not for cars then we would have no roundabouts at all and cycling would be all the safer for it.

Dutch research into roundabout safety

Dijkstra's research into roundabout safety in the Netherlands in 2005 is one of the most referenced articles about this subject. Here's a link. It's written in Dutch and having seen the mess that bad machine translations make of this and similar documents I suggest that if you can't read the Dutch then you're best off going no further than the abstract and my explanation below.

The research drew its conclusions from looking at three different earlier studies each of which looked at large numbers of roundabouts. They're well run studies and the people making them attempted to compare like with like. There was no attempt to study only a subset in order to favour a conclusion already drawn by any of the authors. Dijkstra's article is often used by proponents of priority on roundabouts, though I wonder if they actually read it all the way through. It's very clear about the danger caused by giving cyclists priority on roundabouts.

This graph compares the number of serious cyclist and moped injuries per year (Y) at roundabouts of differing types with differing motor traffic intensity (X). The green line shows the effect of a cycle-lane around the roundabout, which has been known to be dangerous for decades and is recommended by no-one  The black line shows a roundabout with no facilities, cycling taking place on the road amongst cars. The blue line shows the effect of cycle-paths around roundabouts, but this is an average as it is not specified which roundabout design or priority rule it refers to, which is a problem as I'll discuss later.

This graph looks a lot like that above, but it includes all serious injuries in all vehicles, not just those which occur to cyclists. However it is clear from comparing this graph and the one before that roundabouts are, generally speaking, far more dangerous for cyclists than they are for drivers. The relatively small number of motor vehicle occupants who are injured at roundabouts pushes each of the lines upward a little. The effect is especially obvious on the lower, blue line as in this case motor vehicle occupant injuries become dominant as traffic intensity increases. But comparing the two graphs does not make a clear-cut case for all roundabouts with cycle-paths because there is no distinction made between two very different roundabout designs discussed later by Dijkstra.

Three different studies are referenced by Dijkstra, that of Van Minnen/CROW (1998), Weijermars (2001) and Gerts (2002). All three of those studies showed that "with priority" roundabouts are substantially more dangerous for cyclists.

Three studies are summarized by Dijkstra. All studies show worsened safety with cyclist priority ('in voorrang') at roundabouts. Crashes (ongevallen) are between 1.75x and 2.9x more common and injuries resulting in death or hospital treatment (slachtoffers) are found to be between 3x and 6x more common. Gerts' study only reported crashes and not injuries.

Some of the data in the document, such as this example, show all injuries and not just cyclist injuries. Overall, a junction with cyclist priority ('in de voorrang') causes about three times as many injuries.  About as many motor vehicle occupants are injured on the two different types of roundabouts, the difference is made by the radically different results for cyclist safety. See the next table.

The same data from Weijemars is used here, but just the figures for cyclists and mopeds are included.

This table shows the number of roundabouts in total, within urban areas, with cycle-paths, with cyclist priority (470), without cyclist priority (314). These numbers come up repeatedly.

Estimated annual hospitalizations of cyclists and moped riders (on the cycle-path - now largely replaced by e-bikes) in the Netherlands due to crashes with motor vehicles on urban roundabouts. There are about 50% more roundabouts with cyclist priority ('in de voorrang') but they cause ten times as many serious injuries as the safe design of roundabout ('uit de voorrang').

Note that Dijkstra used data from Gerts who referred only to roundabouts which strictly followed the CROW design standards. By doing so both Gerts and Dijkstra tried to exclude potentially worse results which could have come from priority roundabouts which didn't follow the standards. This turned out to be less important than was expected because Gerts found that there was no statistically different result for roundabouts which followed the CROW norms vs. those which did not (bottom of page 13). Also read pages 34 and 35 where this is confirmed. i.e. The difference in safety between differing roundabouts with cycle-paths is almost entirely due to the priority rule. That is confirmed on page 36 where the conclusion is made that there is a significant link between priority and safety.
A note about 'mopeds'. Most of the data lumps cyclists and mopeds together because mopeds are not actually very common. They make up around 1% of the total traffic volume. As a result, I don't expect that their presence here makes much difference to any of the results. Low power mopeds which theoretically are limited to around 25 km/h on the cycle-path are losing ground these days to electrically assisted bikes which travel at a similar speed. Many Dutch people really don't like mopeds, but they do seem to like e-bikes which are now far more numerous. The two modes are quite similar from a safety perspective. There does seem to be an indication that 'with priority' roundabouts are more dangerous for faster cyclists (moped, racing bike, e-bike) who are more likely to surprise drivers because their speed makes them more difficult for drivers to spot, hence the idea that they suddenly appeared "from nowhere" over the driver's shoulder. Faster mopeds (limited to 45 km/h) are banned from urban cycle-paths so are not of interest here.

Comparison with a non-signalled crossing
In order to find a point of comparison for the effectiveness of substituting one type of roundabout or another, comparisons were made of 177 locations where non-signalled crossings ('voor, kruispunt') were converted into roundabouts ('na rotonde').

Note that this is not a comparison with traffic light junctions. That's a completely different story which I have addressed elsewhere: well designed traffic light junctions which separate cyclists in time and space from cars create an almost completely safe space for cyclists and as a result have an excellent safety record in the Netherlands. But they are not discussed by Dijkstra. These comparisons are between roundabouts and the straightforward non-signalled crossings without roundabouts or traffic lights which existed in the same location before they were built.

The comparison over time with non-signalled crossings in the same location across 177 junctions gives us a very good idea of the relative danger creating by giving cyclists priority at a roundabout.

Roundabouts are highly effective at preventing motor vehicle occupant injuries, reduced by 80% on average over the previously existing crossing, however for cyclists they are far less effective. Compared with non-signalled (no traffic lights) road crossings, Dutch roundabouts on average only lead to around a halving of cyclist serious injuries. But this statistic is deceptive because both the 'with priority' and safe roundabout designs have been mixed here to create an average.

In this table they've been separated and we if we consider only the safe roundabouts where cyclists do not have priority ('uit de voorrang') then we see a significant 87% reduction in the number of injuries vs. a non-signalled junction.

By comparison, if we consider only the roundabouts where cyclists do have priority ('in de voorrang'), the improvement in injury rate over a non-signalled crossing is just 11%. i.e. priority for cyclists on roundabouts results in nearly eight times as many cyclist hospitalizations as occur at safe roundabouts when replacing non-signalled junctions. But carry on reading...

The simple conclusion to reach here is that 'with priority' roundabouts achieve about an 11% improvement in safety while safe roundabouts achieve an 87% improvement in safety, making them eight times safer. However it's not actually that simple. Over the same period of time, non-signalled crossings across the country became on average about 10% safer (Dijkstra last paragraph of page 10) so we should perhaps reduce both outcomes by this amount. That would imply that there is actually almost no significant difference in safety between an non-signalled crossing and a 'with priority' roundabout while a safe roundabout achieves about a 77% improvement in safety for cyclists.

How safe are 'with priority' roundabouts in reality ?

This blog post began with one of the first graphs from Dijkstra which showed the relative safety of cyclists using cycle-paths and cycle-lanes around roundabouts with cycling on the roadway on the roundabout itself. Unfortunately, that graph did not distinguish between the different types of Dutch roundabout which include cycle-paths. However later in the same document with the discussion about replacement of non-signalled junctions, Dijkstra calculates the relative safety of roundabouts with and without priority, and we see that the 'with priority' cause nearly eight times as many excess cyclist injuries as the safe roundabout design. I find it unhelpful that both roundabout designs are presented as one item in that graph as they really are not the same.

Below you'll find a modified version of the same graph showing the likely real-world safety of 'with priority' roundabouts vs. the average for all cycle-paths on roundabouts, cycle-lanes and cycling on the road:

The red line shows what the probably injury rate is for roundabouts with priority cycle-paths in the Netherlands. The blue line is an average for all roundabouts with cycle-paths. A line which represented only safe roundabouts would be lower than the blue line, especially in the first half of the graph.

You'll note that up to around 10000 vehicles a day there is no great difference between the black line, showing the rate of injury for cyclists riding on the road, the green line showing a cycle-lane painted around the perimeter and the red line showing the injury rate for cyclists on 'with priority' cycle-paths. Therefore swapping between a roundabout design where cyclists ride on the road to a design where they use a priority cycle-path should not be expected to bring an improvement in safety. The only option which always looks good is the blue line showing as an average for all roundabouts with cycle-paths, which is skewed downward by the greatly improved safety of the safe roundabout design over the 'with priority' design.

Explanation of the red line: Over half of all urban roundabouts in the Netherlands gave cyclists priority when Dijkstra's graph was created. He found that on these roundabouts about eight times as many injuries per year could be expected. i.e. the corrected data for with priority roundabouts should be at about four times the level of that for the safe roundabouts. The red line which I have added to the graph is at approximately three times the height on the Y axis of that for both types of roundabout combined. This places it at approximately at the level we would expect to see if the two different types of roundabouts had been  treated as two different cases.

Explanation of blue line shape and stippled red: The blue line, for all roundabouts with cycle-paths, has a rather unusual shape, with a peak at around 10000 vehicles a day before dipping downward and rising again with motor vehicle intensity. I believe that this is caused by priority roundabouts causing the vast majority of crashes and injuries but being built mostly in places with lower motor vehicle intensity. As a result, the blue line is pushed upward in the first half of the graph by crashes on 'with priority' roundabouts, but I think the second half of the blue line is made up to a higher extent of data for safe roundabouts. I used a stippled red line from ~10000 onward because it's likely that it is no longer reliable past this point for the same reason. Unfortunately the separate data is not available so that I can test this hypothesis.

Politics

Back in 1998, SWOV's own research already demonstrated a worse safety record for 'with priority' roundabouts. Their research indicated that 52-73 extra cyclists would find themselves in hospital with serious injuries each year if that design was used. Despite this concern, a political decision was made to go along with a standard recommendation that cyclists should always have priority on urban roundabouts. This happend after they were given two re-assurances: first that the new standards advised by CROW would be applied everywhere and second that introduction of these standards would result in improved safety for 'with priority' roundabouts.

Unfortunately, the expected safety improvement was not realised. This was not merely because the guidelines still were not followed in all cases, but because it was discovered that the guidelines didn't actually have a measurable effect on safety even where they were followed. In an appendix on pages 29 to 35 of Dijkstra ("Voorrang voor fietsers: effect van vormgeving?") it is shown statistically using data gathered from many real world roundabouts spread across the country over five years that there is no detectable difference in safety between 'with priority' roundabouts which adhere strictly to the CROW guidelines and those which do not. Therefore it would seem that roundabouts with significant differences from the norms (e.g. different radii, crossings too close to the roundabout, inadequate road markings, allowing bidirectional cycling around the roundabout etc.) were not worse from a safety perspective at all. The research suggests very strongly that exactly following CROW's guidelines is not important for safety at all. Just one thing makes roundabouts with cycle-paths dangerous and that is giving cyclists priority.

Since the decision was made to go along with the "with priority" guideline in urban areas, the number of roundabouts in the Netherlands has tripled. For that reason we can now reasonably expect that instead of 52-73 extra cyclists receiving injuries resulting in hospitalization or death each year that there are now between 150 and 210 more than would have been the case if the safe roundabout design (used all over Assen with extremely low injuries as a result) had been standardized upon across the entire country.

The CROW argument that roundabouts with priority are "slight less safe" than the safe design was based upon the 52-73 extra casualties being only between 1.8 and 2.5% of the total. Unfortunately, with their number having tripled, we can now expect that these dangerous roundabouts account for between 5.4% and 7.5% of cyclist casualties per year, which is certainly not insignificant. Given that after a period of decline, Dutch cyclist deaths are now rising once again, this is something we should be looking at more closely. We already know how to reduce injuries on roundabouts by 87%. We just have to switch to building the proven safe roundabout design.

Cambridge

So now back to Cambridge. Why did that city outside the Netherlands adopt a design has been proven to cause excess injuries and deaths in the country where it came from ? Why are they following a decision which was made in the Netherlands for political reasons and not based on safety ? Personally, I think they were extremely badly advised.

Valkenswaard roundabout visited in 2006. Not a safe design.
See statistics. This roundabout does not conform 100% to
CROW standards, but as you can read above, we now
know that it probably wouldn't make a difference if it did.

Now I take a little responsibility for this because I used to live in Cambridge, I was a member of the Cambridge Cycling Campaign who campaigned for Dutch style cycling infrastructure to be built in that city, and I organised study tours in the Netherlands for members of the campaigning group and people working for the council. Indeed, on the first of these study tours, way back in 2006, I was myself enthusiastic about the cyclist priority design of roundabout and I showed it to people from Cambridge.

However my enthusiasm for priority roundabouts didn't last long after I moved to the Netherlands, experienced near misses on these designs, learnt Dutch and read Dijkstra's and other studies of roundabout safety. I change my mind when presented with contrary facts and it's simply not possible to continue to believe that these designs are safe when they clearly are not. That is the reason why I promote the safe design of roundabout, especially in countries outside the Netherlands.

The advantage that the safe roundabout design has is of complete predictability for the cyclist. As a cyclist you can take control of your own safety. While mistakes made by drivers on priority roundabouts where the driver does not cede priority often result in crashes and cyclist injuries, drivers on safe roundabouts who make errors typically just slow or stop when they need not have done. This can actually be slightly annoying for a cyclist who has adjusted their speed to slip across the road before or after any given car, but it's a safe failure mode which doesn't result in injury.

There is also the potential difference between British and Dutch drivers. I've not only cycled but also driven in both countries and I think the ability to drive safely is quite similar between the two countries. However there is a difference in behaviour in that Dutch drivers typically drive more slowly, at least on minor roads and in towns, and that there is less aggression. This is probably also a function of the unravelling of routes which keeps drivers who are minutes late for their destination from making through journeys near cyclists. They are also used to the idea of ceding priority to cyclists on roundabouts and elsewhere, and most people here do cycle. What effect this difference in driver behaviour will have on a roundabout design which requires drivers to cede priority in order to ensure cyclist safety is currently unknown.

Unfortunately the mistake in Cambridge goes far beyond just choosing a poor and dangerous design of roundabout. Their ambition unfortunately went no further than substituting one roundabout design for another and it is now being heralded as a victory for cycling before we even know whether it turns out to be safe in this location. In reality there is no roundabout design which has ever been built for the benefit of cyclists. They're all just ways of trying to address the problems caused by motor vehicles.

Most road junctions in Dutch residential
areas look something like this. Much
more common than any traffic light
or roundabout design, a non-signalled
junction in a residential area, with 30 km/h
speed limit, raised table, small corner
radii, and most importantly it's not a
through route for motor vehicles.

Addressing the problems of motor vehicles could have been done in many other and more effective ways. The roads leading to the location of Cambridge's new roundabout are places where people live. Residential streets which have for years endured high traffic volumes. If they had their usage changed so that they no longer had to support that through motor traffic (already done on a tiny scale in Cambridge) then the roundabout probably wouldn't be required at all. A simple non-signalled junction but with very cars, or if a stream of traffic was required to flow between two arms of the junction perhaps a signalled crossing, would have resulted in a better outcome for cyclists.

You could have asked...

There are few people who have lived, worked and cycled on an everyday basis in Cambridge for more than a decade and who have then done the same in a Dutch city for more than a decade. Fewer still who have written about cycling for decades, about cyclist roundabout safety and made suggestions for how countries outside the Netherlands can best learn from the Dutch experience regarding roundabouts and other infrastructure. Still fewer who have gone to the effort of learning Dutch, reading the research and trying to advise on the basis of that research, and I would guess that also bringing people from the council and the local cycle campaigning group in Cambridge to the Netherlands in order to demonstrate to them the pros and cons of different roundabout designs amongst many other things on top of those other things would make me pretty much unique. I'm also not hard to find.

So do you think anyone from Cambridge ever thought to contact me about their new roundabout ? Of course not. Actually that's a bit unfair. A couple of people on the periphery who were concerned about the direction in which that was going did make contact and I have heard from them how what I'd written was dismissed rather rudely. But why ? Did they have some other local expert who could read the Dutch documents in depth and translate them ? Did they not believe the stats therein ? Did they expect that a design which is relatively dangerous in the Netherlands with Dutch drivers would somehow be less dangerous in the UK ?

I of course don't expect any answers. But it's a shame. I could have helped. I fear that Cambridge will regret what has been done. Not now. Not soon. It'll take a while before you have stats - the Dutch research on which I based my advice was itself based on the stats from many roundabouts over many years. The stats above are based on up to 940 rotonde-jaren, or roundabout years. These results have not been cooked up after just looking at a single location for a few weeks.

Conclusion

I am left with a fear that what Cambridge has done is merely to replace one dangerous roundabout design with another. It's a pity that they have done this because it's been done with such a lot of publicity and this may tarnish the concept and make it more difficult to adopt a better design elsewhere. Britain's cyclists need safe infrastructure. It's high time that they got it instead of ineffective projects like this example. However this is just one junction in one city of a country of many millions of people. It won't in itself make a huge difference one way or the other. No single junction ever could do that.

What is required, in Cambridge and elsewhere, is to start looking at the bigger picture. It is a mistake to think that any real change can result from a piecemeal one junction at a time approach. The UK, and everywhere else, needs a complete grid of effective safe and attractive cycle-paths in order to enable efficient go-everywhere cycling. The Netherlands is fabulous for cycling not merely because some of the roundabouts are safe (as you can see above, some certainly are not). An holistic approach makes the difference. There is nothing new and novel about any of this, it's been known for forty years.

Planning occurs in the Netherlands on a much greater scale than in the UK. There are traffic circulation plans which limit the effect of motor vehicles on residential areas and direct cycle routes. Almost all roundabouts form part of a plan which removes motor traffic, especially through motor traffic, from locations where cyclists need to be to make everyday journeys. This makes even less safe designs safer. But removal of motor traffic can even result in a much bigger prize: the removal of roundabouts and traffic lights altogether from cycling routes. Cyclists don't themselves need either of those types of junctions. They are not actually for us, but exist only to moderate motor traffic. There exist very good traffic light designs which benefit cyclists and roundabouts which do likewise but in both cases these things should only be built where there is no choice. i.e. where it's impossible to get rid of the motor vehicles. Cyclists are always better off without big road junctions. This has happened on a large scale at least around the centre of most Dutch cities, spreading outward from the centre in many cities and into the renovation of old suburbs and the design of new suburbs. The process did not begin by changing the design of a single busy junction which will remain busy, but then making a lot of noise about it as if a great change has been achieved.

The piecemeal approach, resulting in years of little or no real action and the effect of such small forward steps as occur usually being swamped by backward steps elsewhere, is precisely why people in the UK have gone from saying that their country is 20 years behind the Netherlands to 40 or 50 years behind. It's only possible to catch up by doing the hard work required to make things better, consistently over years. This is something which no country can afford not to do: when all things are considered, it's cheaper to build cycling infrastructure than it is not to build it.

Update May 2023
Three years later we now have reported collision data for the Cambridge roundabout. In the three years since the roundabout was rebuilt as "Dutch" style there have been 10 collisions, including three which caused serious injury. In the three years before the change there were just six of which none were serious.

I'd been advising people in Cambridge about roundabout designs for well over a decade before they ignored my advice and chose to build this dangerous design instead. They now have injured cyclists as a result of their choice. I take no pleasure in saying that "I told you so", but I did tell them, repeatedly, and the result that they now have is just what I predicted.

Zwolle: The Dutch city which changed its roundabouts from one unsafe design to another unsafe design

I've written three times before (1, 2, 3) about how the roundabouts in Zwolle cause danger for cyclists. Each time, I've pointed out that the use of the "priority" roundabout design in that city results in those roundabouts always featuring as the most dangerous sites for cyclists in the entire city.

The top ten list of most dangerous locations for cyclists in
Zwolle according to the Gemeente. Three are roundabouts.

This has now been confirmed by the local government (Gemeente Zwolle) itself, which admits that the most dangerous place for cyclists in the city is the roundabout pictured above at the junction of the Burgemeester Roeienweg and Pannekoekendijk.

Zwolle's local newspaper has covered this issue several times in the last year and this helped to prompt the local government to produce a top ten list of the most dangerous places in the city for cyclists.

Gemeente Zwolle's top ten list shows that they consider three of the ten most dangerous places in the city for cyclists to be roundabouts. The top location is precisely the same roundabout as I identified as being the most dangerous in the city when I first wrote about the problem of adopting unsafe roundabout designs back in 2014.

The top ten list of most dangerous places for cyclists in
Zwolle according to newspaper readers: Five roundabouts.

The newspaper also surveyed local cyclists who gave a subjective response about how unsafe various places in the city feel. They placed the most dangerous roundabout in fourth place and pointed out several other problematic roundabouts as causing a problem. The worst place according to local cyclists is the "Fietsrotonde".

The fietsrotonde opened in 2013 to claims of safety and much press coverage. Many people praised the new design but I did not because it was unproven. Instead, I pointed out in 2014 that the claims of safety for the fietsrotonde were premature, that I thought the design was confusing and that it gave little chance for recovery from error.

A little later in 2014 I unfortunately had to update my blog post to point out that it had already claimed victims.

Zwolle's Fietsrotonde. It requires perfect behaviour from all
users and much head swivelling from both cyclists and drivers
to predict what each other will do. That is why it's unsafe.
Update: Another crash. 

The subjective view of local cyclists that this junction is difficult to navigate safely is accurate and it results from the same problems as occur with the roundabouts in Zwolle: Cyclists must their "priority" by riding out in front of motor vehicles while relying upon drivers to maintain the safety of cyclists. This never feels safe and it never truly is safe. Drivers are frequently distracted, they often don't see cyclists until it is too late, and of course a fair number are simply not very skilled at driving so cyclists should never be expected to place their safety in the hands of drivers.

Crossing the road
When I wrote about Zwolle's roundabouts a second time (in 2015) it was as part of a blog post about the nature of the most dangerous locations for cyclists in several different Dutch cities. Amongst the most dangerous things that a cyclist or pedestrian can do in a modern city is crossing the road. At uncontrolled crossings our safety is very much in the hands of drivers and this is why uncontrolled crossings and junctions expose cyclists to great danger. While the safe roundabout design which I have been promoting for the last four years almost completely eliminates this danger to cyclists using the roundabout, the unsafe roundabout design as used in Zwolle offers only a very small improvement over an uncontrolled junction (research found just an 11% difference). It should be no surprise therefore that when I went looking for the most dangerous locations in various cities, I found that cities which had adopted the safe roundabout design (like Assen) did not have roundabouts amongst their most dangerous locations for cyclists, while those cities which used the less safe design frequently had roundabouts as amongst their most dangerous locations.

You'll note that Zwolle's local government listed many crossings (kruising) as well as roundabouts (rotonde) in their top ten list. If they had adopted the the safe design of roundabout then their list would probably not have included any roundabouts at all but instead would be made up almost entirely of crossings. Zwolle would have been safer for cyclists than it is.

It may seem quite a big request to make that a city should change its roundabout designs. In Zwolle's case they have actually made this investment. Unfortunately, though, rather than adopting the safer design they spent their money and time converting their roundabouts from one unsafe design to another and as a result they have not improved the safety of cyclists...

After being improved, the most dangerous roundabout remains the most dangerous
When I wrote about Zwolle's roundabouts in 2014, many people were quick to point out that the design of the roundabout was less than optimal. There was little distance between the cycle-path and the road. Claims were made that had this been otherwise, the roundabout would have been safe. We now know that this is not so. This particular roundabout has been changed in design quite radically yet it remains the most dangerous location in Zwolle for cyclists.

Both photos show the same roundabout and this is the same location as at the top of the page. Safe roundabouts don't look like either of these two examples. Neither the "before" photo nor the "after" photo are safe. I pointed out that the first was the most dangerous roundabout in Zwolle in 2014 and Gemeente Zwolle themselves have now pointed out that the "improved" version of the roundabout remains the most dangerous location in the whole city for cyclists in 2018.

Zwolle is now considering changing this design once more to try to make it safe. We should not keep making the same mistakes. There is a better alternative.

The truly safe design
This design is truly safe. Cyclists and drivers meet each other at 90 degrees so that sight lines are maximised. Speeds are reduced by camber on the road and the curves on the cycle-path so that both parties have as much time as possible to make decisions. Priority at the crossings is given to motorists because they have the greatest power to cause harm and the least "skin in the game". Cyclists are prioritized by having bidirectional cycle-paths so that they cross less often and because they can always turn right without considering motor vehicles at all. Please read the entire blog post from 2014 about why this particular design is special and watch a video which explains further.

Dutch cities which use this design see radically fewer cyclist injuries on roundabouts than Dutch cities which adopt the same designs as used in Zwolle.

Safe roundabouts revisited: There's increasing evidence that one particular design really is the safest for cyclists

The safe roundabout design for cyclists looks like this. Please
read my previous blog post and watch the accompanying
video as both of those describe the features of this design

There's been quite a lot of news recently about roundabouts in the Netherlands and I'm pleased to say that the new statistics are highly supportive of my previous article about how a truly safe roundabout should be designed for cyclists. Here in Assen we use this safe design instead of the design used in much of the rest of the country and as a result far fewer cyclists are injured on our roundabouts. Injuries occur elsewhere quite frequently, and it estimated that between 100 and 150 more cyclists a year end up hospitalized because of the unsafe design adopted elsewhere, but the safe design greatly reduces their rate to the point that I don't know of any which have occurred on the particularly safely designed roundabouts in this city. Please go and read my previous article linked above to find out safe roundabout designs.

Now on with the new content:

Dangerous roundabout designs are a continuing issue in the Netherlands
Data from the Smart Traffic Accident Reporting system has been used to create a map which shows the most dangerous roundabouts in the Netherlands. I've picked out below some of the Dutch cities which I've written about before and shown how they rate for roundabout safety. There's a colour code in use. Roundabouts which have caused no problems are not shown, roundabouts with a yellow dot have seen a small number of collisions, orange dots are worse and red dots are the worst locations of all. The colour code doesn't tell whether collisions resulted in injuries.

The outcome is obvious. Every city in the Netherlands which uses the dangerous cycle priority roundabout design, regardless of the details of how their roundabouts are built, has a heightened rate of injury of cyclists. To give a point of comparison, first consider Assen, which has only the safe roundabout design:

Assen

The interesting thing about the map is that it so strongly reinforces the data which I based my previous blog post upon: Only seven of Assen's 21 roundabouts are visible on this map because almost no crashes every occur here on the roundabouts due to the safe design. On those rare occasions when there is a crash it usually results only in minor bodywork damage to cars and that is the case for all the crashes which occurred. Between 2014 and 2017 there were just eight minor crashes with material damage to cars between all 21 roundabouts in Assen. There were no injuries. Annual crash rate: 1 for every 32000 population per year. Injury rate: 0. No-one at all was injured on a roundabout in Assen during this period of time.

Groningen

Groningen is our first example of a city which gives cyclists priority on the roundabouts. Here we will not see the same zero injuries result. Note that on this map we have not only yellow dots but also orange and even red dots indicating sites with far more crashes. Not only were there considerably more crashes, 96 in total, but 26 people were injured severely enough that they had to attend hospital as an in-patient as a result of crashes at Groningen's roundabouts in the same 2014-2017 period. Groningen's population is three times greater than Assen but clearly the roundabouts in that city create far more than three times the danger. Crash rate: 1:7500, Injury rate: 1:28000. i.e. one in twenty-eight thousand of Groningen's population is hospitalized each year by the roundabouts in use in that city.


Zwolle

Zwolle's population is 125000 which makes just under twice the size of Assen. This city also uses the dangerous design of roundabout and again you see orange and red dots where many crashes have occurred. 105 crashes resulted in 37 people being hospitalized at the roundabouts in Zwolle between 2014 and 2017. Three years ago I identified one of Zwolle's roundabouts as the most dangerous place in the city for cyclists and it's highlighted on the map above having caused three more injuries. Crash rate: 1:4800, injury rate: 1:13500. One in every 13500 people in Zwolle is hospitalized each year by Zwolle's roundabouts.

Please read a more recent update about the danger of the roundabouts in Zwolle. Zwolle went to the effort of rebuilding roundabouts but they chose a different unsafe design to replace the unsafe design they already had. As a result, even the local government of the city has had to admit that three of the top ten most dangerous places in the city for cyclists are roundabouts.

's-Hertogenbosch

The population of 's-Hertogenbosch's 152000, which makes it about two and half times the size of Assen. The city uses the dangerous design of roundabout and they caused 105 crashes with 34 injuries over the 2014-2017 period. Three years ago I assessed two of the two of Den Bosch's roundabotus as being the most dangerous places for cyclists in the whole city and one of those is highlighted above showing the that it has caused three more injuries. Crash rate: 1:5800, Injury rate: 1:17900. One in every 17900 people is hospitalized each year in Den Bosch each year due to the roundabout designs used.

Enschede

Enschede's population is about 160000 which makes it also about 2 and half times the size of Assen. Enschede was the first city to use the dangerous "priority" roundabout design. Three years ago I identified the roundabout highlighted above as the most dangerous in the city for cyclists and clearly it has continued to injure people. In total, 80 crashes occurred at Enschede's roundabouts between 2014 and 2017 and 10 people were wounded. Crash rate: 1:8000, Injury rate: 1:64000

Middelburg

The same pattern is seen even in small cities which use the dangerous roundabout design. Middelburg is a small city in the South West of the Netherlands with a population of just 48000, about 2/3rds the size of Assen. There are relatively few roundabouts but the design used is the dangerous "priority" design. Middelburg's roundabouts have caused a total of nine crashes in which five people have been hospitalized. A crash rate of 1:21000 and a hospitalization rate of 1:38000 per year.

Drachten

Drachten is also smaller than Assen with about three quarters of the population yet its roundabouts have caused a total of 32 crashes, 8 injuries and one death over the period when Assen's roundabouts caused no injuries at all and just eight minor crashes. The roundabout which is highlighted for Drachten is the shared-space "squareabout" at the Laweiplein, which on its own is responsible for five crashes and two injuries. Unfortunately, there are many exaggerated claims made for the safety of this junction when it is actually a very unsafe design. Please read my previous post on the subject of the Laweiplein for more details. Crash rate: 1:5600, Injury rate: 1:22500, Death rate: 1:180000

More Shared Space roundabouts ?
Given the poor track record of Shared Space in general and the poor track record of the Shared Space roundabout in Drachten, you might think people would steer clear of the concept. But that's not happening: A new shared space roundabout was recently built in Winschoten and it's got such a bad record already that it was recently recognized as the most dangerous roundabout in the entire country with just one location having caused 13 crashes and 3 injuries. Winschoten's population is only about 18000 but this roundabout is so bad on its own that we get a crash rate of 1:5500 and an injury rate of 1:24000 per year for the population while ignoring everything else in Winschoten.

Winschoten's Shared Space roundabout - recently chosen as the most dangerous in the country. Truly a horrible design. No-one knows what they're supposed to be doing and uncertainty results in accidental risky behaviour.
Are we designing for efficiency and safety ?
The crash and injury rates quoted for each city above are a primitive way of making a comparison, simply dividing the population by the average annual rates of crashes and injuries without any other factors, but nevertheless, the point as does all the other data, towards Assen's roundabouts being amongst the very safest in the Netherlands. So why isn't the rest of the country copying this safe design ?

We shouldn't be surprised by this result. It was predicted 13 years ago.
It's been known for many years that the design of roundabouts which gives cyclists priority over motor vehicles around the edge of the roundabout, relying upon drivers always to spot a cyclist who might emerge quickly from a blind spot and assuming that all drivers pay attention to ensure the safety of others as they drive, inevitably results in more injuries. In 2005 the extra injuries resulting from this design were estimated as 52-73 people requiring hospitalization (in-patient treatment) each year.

Roundabouts in the Netherlands over time

Since 2005, the number of roundabouts in this country has nearly doubled. It is also claimed that more journeys are being made by bicycle than before and there are more cars. Therefore it's reasonable to assume that the number of extra injuries requiring hospital treatment due to the priority roundabout is now around 100-150 per year. That is perhaps why the injuries on roundabouts are now getting more press attention than before. But these extra injuries shouldn't be a surprise to anyone because this was predicted before half of the roundabouts which exist now even existed.

If more than a hundred people per year are being injured due to a choice of roundabout design when a much safer design which is proven and already in wide use could be adopted, there needs to be some other justification for the unsafe design. Typically, people claim that it's more efficient for cyclists to have priority, but unfortunately the "priority" is merely part of the name of the design and not any proven effect. In reality you can't ride around a priority roundabout as quickly as you can ride over the safe design because you have to be quite cautious when you're relying on others always to look out for you. In fact, many "priority" roundabouts are quite unpleasant and inefficient for cyclists because we are forced to cross more lanes, which means slowing considerably and repeatedly checking whether drivers approaching in both directions who are supposed to have noticed us actually will give way to us, and the much tighter corners on the priority design often cause trouble.

Are we just adopting the "priority" design because that word sounds good ?
A few days ago I rode through a particularly poor recently built example of a "priority" roundabout, one which bizarrely has been held up as a good example locally. This morning I went back to the location especially to make a video showing how extraordinarily inefficient a "priority" roundabout can be, and how it can expose the cyclist to needless extra danger:

This video shows my pick for the most inconvenient newly built roundabout anywhere in the North of the Netherlands

Not all of the poor features of this roundabout and surrounding infrastructure are included in the video. This gentleman clearly had ridden on the "wrong" side of the road, treating a narrow unidirectional cycle-path as bidirectional. People do that if the infrastructure makes doing the wrong thing more convenient than doing the right thing. Once you reach a priority roundabout when travelling in the wrong direction, all bets are off for safety.

If I had made a return trip through the roundabout in the video I would have ridden here. This skips the indirection to the other side of the road, but instead riders have to cross three lanes of traffic, the first of which is a bus lane, and pass over two islands, neither of which is wide enough to offer safety even to a child's bike. I suspect that in reality few people go all the way around in the video so there will be many people riding in the wrong direction here. That is far more dangerous because they'll be relying upon drivers looking in both directions at once across three lanes for their safety and they haven't got any refuge to hide in.

Stills from the video above. How can anyone in any seriousness claim that the "priority" roundabout on the left, which requires cyclists travelling South to North to turn sharply and cross six lanes of traffic to go all the way around the roundabout, is safer or more convenient than the one on the right where cyclists cross two lanes of traffic in a straight line with good sight-lines ?

Summary
The safe design is well established and has a proven track record. It also is naturally resistant to error in implementation due to imperfect copying of the design, making an ideal basis for other countries to create their own safe roundabout designs for cyclists.

The "priority" design is proven to cause a significant level of injury to cyclists in the Netherlands and even here is misinterpreted quite often in such a way that it is more dangerous than it need be and causes significant inconvenience to cyclists, as shown in the video above.

The roundabout design which should be copied by countries outside the Netherlands is therefore the safe roundabout design. Copy what is proven to work, not merely anything that is "Dutch".

On our study tours we demonstrate the difference that good infrastructure makes. Roundabout designs are included.


Danish Study
A new study from Denmark provides more supportive evidence. In particular (from the Abstract): "Single-lane roundabouts with separate cycle paths, where cyclists must yield to motorists entering or exiting the roundabout, are safer than roundabouts with cycle lanes." It doesn't matter which country they are inplemented in: the principles of safe roundabout design remain the same.

Update December 2019 - new Dutch study
A new Dutch study which analyzed the safety of all roundabouts in the Netherlands has shown that four times as many cyclists are injured on roundabouts where cyclists have priority as on those where they do not. The study further notes that roundabouts with bidirectional cycle-paths are safer than those with unidirectional cycle-paths. It is of course the case that almost all of the safe without priority roundabouts use bidirectional cycle-paths while these are less common (and less safe) on the with priority roundabouts, so that's further supporting evidence

The Slow-Turbo Roundabout. A promising new Dutch roundabout design and why you should NOT copy it

A few days ago a new Dutch "slow turbo" roundabout design appeared in images on Twitter. Ordinarily, turbo roundabouts are used in the Netherlands to deal with large volumes of high speed motor vehicles in locations such as motorway junctions, which are rarely visible to cyclists and pedestrians, but this new design is intended to be used in areas with high volumes of cyclists and pedestrians:

A promising design, but with unproven safety record so don't copy this yet.

This roundabout is interesting because it combines the safe layout of the proven safest Dutch roundabout design with priority for cyclists at the crossings, when similar layouts have previously only been used where drivers are given priority at the crossings. Extra care has been taken in the design to try to ensure cyclist safety at these priority crossings - a factor which has been proven in the past to lead to a sharp reduction in safety.

A particularly poor "with priority"
design. No sight-lines, no reaction time
Frequent injuries at this location.

This design attempts to reduce the safety problem for cyclists with priority at roundabout arm crossings by a number of measures:

1. It slows both cyclists (by tight corner radii) and drivers (by use of narrow lanes with raised tables), giving both more time to react at the crossing.
2. Good sight lines are ensured because cyclists and drivers cross at right angles to one another.
3. While turbo-roundabouts require multiple lanes, this design keeps the cycle crossings far enough from the roundabout that cyclists are required to cross only one lane of motor vehicles at a time.
4. A generously sized safe refuge is provided between the two streams of traffic.
5. The crossings being placed at a considerable distance from the roundabout itself means that the moment in time when drivers negotiate with cyclists on the crossing is distinctly different from that when they have to negotiate with other drivers on the roundabout.

Why it may not be so safe as is hoped
I think there is great promise in this design but I must sound a note of caution.

Raised tables slow motor vehicles where
cyclists have priority at the crossings, but
they resemble less successful crossings.

I am enthusiastic about the possibilities for this type of roundabout because it follows the good design principles of the proven safe Dutch roundabout design as I discussed in the previous section and that it also gives cyclists priority (everyone wants priority), but I also see reasons why it may fail to be safe. For instance:

1. The distance between the crossings and the roundabout is quite large, but for drivers entering the roundabout the distance between the crossing and the point where they need to choose a lane is very short. This may distract drivers such that they are less likely to notice cyclists.
2. Raised tables on straight roads have only a slight effect of slowing drivers. When I looked at three different priority crossings a few days ago, the crossings where drivers were effectively slowed had more measures than just a raised table and the example which barely slowed drivers at all looked very much like these crossings.
3. This isn't the first time that priority has been combined with a layout which provides better sight-lines. For example, one attempt to design a roundabout in Eindhoven combining good sight-lines with cyclist priority resulted in some injuries.

I remain hopeful about this design, but we must keep in mind that it is an experiment.

Experiments are not always successful
Without experimentation we can never discover new and perhaps better ways of doing things. The Netherlands leads the world in cycling infrastructure design, and experimentation continues here. This is a good thing. But ideas should only be adopted more widely if they have been proven to work safely and efficiently.

Experiments which didn't work out so well include an experimental cycle-path surface which was installed near Assen in 2009, but then replaced again in 2013 after it had proven not to provide an adequately comfortable surface for cycling.

There was also the Zwolle "fietsrotonde" for which bold claims were made in advance, but where poor design caused injuries within months of opening.

As of right now, there is precisely one roundabout of this new design in the world. It should be viewed as a brave and worthwhile experiment and it may eventually form the basis for yet safer conditions for cyclists in the Netherlands, but it should not yet form the basis for other experimentation elsewhere. We do not yet have long term accident statistics for this design and it is premature to make any claim about whether or not this new design is in fact safe.

Note also that the new design requires a very large footprint in order to provide the required sight-lines and space for the lanes of the turbo roundabout. As such, it's unlikely to be able to be applied everywhere.

What to adopt in other countries
For experimentation elsewhere it makes most sense to copy the proven safest Dutch designs. So far as roundabouts are concerned, this is it:

This design provides the best basis for emulation elsewhere. Such roundabouts have the the best safety record within the Netherlands and are likely to remain safe even if aspects of the design are compromised.

The safest design currently in use in the Netherlands, shown in this photo, places the emphasis on cyclists to look after their own safety rather than relying upon perfect driver behaviour to keep cyclists safe. This is one of the reasons why this design is successful. The same principles have also been shown to work on similarly designed roundabouts with considerably smaller footprints.

Awful roundabout design from London
widely described as "Dutch", but
actually nothing of the sort. This is
one of many awful recent proposals
from London, none of which are
similar to Dutch designs which they
claim to have copied.

The details of any design are important. Distance between roundabouts and crossings, heights of raised tables, lane widths, road camber, geometry are all important and none of these should be taken as being the sole reason why Dutch roundabout designs are safe for cyclists. It should also be noted that roundabouts are only used by cyclists in the Netherlands where traffic volumes and speeds are relatively low and are controlled. Unfortunately, it is not uncommon for designers elsewhere to completely misunderstand how Dutch roundabouts achieve their safety. "Cargo-cult" style copies of Dutch roundabouts built in the UK in Bedford, Cambridge and York without the safety features of the Dutch roundabouts which provided inspiration and as a result they are not so safe.

In order to try to assist planners and campaigners alike to make the right choices, we offer cycling study tours which take a unique, independent, view of Dutch cycling infrastructure and which explain everything in plain (native) English. Book a place to discover more about what works well and should inspire new infrastructure design elsewhere as well as what works less well and should not be copied.

Find out how how things really work in the Netherlands before trying to copy anything.