Monday, 17 August 2015

The most dangerous junctions in Assen and other Dutch cities. What makes junctions dangerous ? What can we do to address that danger ?

Though there isn't a huge amount of traffic at this location, and though speeds aren't particularly high (this is an intersection in a residential area between a 50 km/h road and 30 km/h roads), this is the most dangerous road junction in Assen for cyclists. It doesn't look like much - just a simple road crossing. But simple crossings like this can be dangerous for cyclists.

The problem at this junction is recognized. It led to a redesign
early in 2015 which makes the junction look a lot smaller
than it did. It is not yet clear whether this will be enough
to address the safety issue in this location. Given that the
change was minor and near misses still happen here, I'm not
sure that I believe enough has been done..
This junction was the scene of seven cyclist injuries in the six years between 2007 and 2013. Compared with other cities, especially in other countries, this number is low. For instance, I once wrote about how a single junction in Cambridge had seen 43 crashes with cyclists in six years and how another in London managed to ring up 89 cyclist injuries in just two years. Assen's most dangerous junction perhaps cannot compete with the danger faced by cyclists elsewhere, but this doesn't mean that there is no problem. These most dangerous places could be better.

This junction stands out in large part because cycling in Assen is very safe. Seven cyclist injuries at one location is exceptional because in the same time period just 11 cyclists were injured at all of Assen's 28 locations with traffic lights put together and just two cyclists were injured across all 21 roundabouts.

The very good safety record of Assen's roundabouts is due to adopting a very safe design.

The traffic light junctions have a less obviously impressive safety record but this should be balanced against there being more traffic light junctions than roundabouts and due to traffic light junctions dealing with heavier motor vehicle flows than roundabouts. Many of the traffic light junctions used by cyclists in Assen have a design which is exceptionally convenient and particularly safe for cycling.

If Assen had not adopted such safe designs for larger junctions then it is likely that uncontrolled junctions like this would not be the most dangerous places for cyclists. But as a result of that policy elsewhere, the second and third most dangerous junctions in Assen for cyclists are also uncontrolled junctions - in this case where cyclists have to cross roads unassisted by traffic lights. These caused five and four cyclist injuries each (+ two fatalities - one of a cyclist and one of a moped rider).

Two weeks ago I took a follow-up study tour group to see why
this junction is dangerous. While we were there, both Charlie
and Mark photographed a near-miss. The cyclist was not
surprised to be told that this was an unsafe junction. The
driver was shocked by her mistake. Note that this happened
after the re-design which is supposed to have improved safety.
Why uncontrolled junctions are dangerous
The problem with uncontrolled junctions is that they rely upon perfect driver and cyclist behaviour for their safety. If everyone always behaves correctly, everyone always manages to work out exactly what every other participant in traffic is doing, no-one is ever distracted or makes mistakes, then these junctions work perfectly. Unfortunately, these junctions actually have to be used by real human beings and people do make mistakes.

Dutch drivers and Dutch cyclists are not special. They're people too. Given them confusing situations and they'll make mistakes in just the same way as do people elsewhere.

The problem with this particular junction was illustrated vividly to us on a recent study tour when a near miss was caught on camera (above). This was a genuine SMIDSY ("Sorry Mate I Didn't See You") incident. The driver simply had not seen the cyclist. Luckily, she took a second glance left and stopped her car just in time so that no collision occurred. Both parties were shocked by what had happened.

Let us consider the pressures on this driver as she wished to pull out of this junction and turn right: At this position, the driver has much to too. She needs to check for cyclists in her own street who may try to overtake on either the left or right side of her car and who may potentially conflict with a right turn and also check the cycle-lane on her left for cyclists (including the one she missed). She also needs to bear in mind what drivers might do - both those approaching from behind (hesitation may result in being rear-ended) as well as those going both left and right on the road she's pulling into and also those approaching from dead ahead who may turn across her path. This requires a lot of concentration and also a lot of head swiveling in order to look in all directions at once.

The danger at uncontrolled junctions is due to many pieces of information to be processed at once.

The most dangerous junctions in other Dutch cities
Uncontrolled junctions are not the most dangerous locations in every Dutch city, but they do appear quite often. For instance, Groningen's most dangerous junction for cyclists is an uncontrolled junction which is also the most dangerous junction for all modes in the whole country. 12 cyclists were injured across both sides of the junction over a period of six years.

Second place in Groningen is a tie between two junctions, each of which injured six cyclists: One of these is a different uncontrolled junction and the other location is a roundabout of the unsafe design in an older suburb which allows through traffic (read more about suburbs further down the page).

This is the safe roundabout to copy.
Unsafe roundabouts:
The unsafe roundabouts in Groningen (see the last paragraph) follow a design where cyclists have priority over other traffic by using a concentric circle cycle-path around the main roundabout. Unfortunately, this is nearly as difficult for drivers to use correctly as an uncontrolled junction, with a requirement to keep track of cyclists and cars from several directions at once and involving nearly as much head swiveling as an uncontrolled junction. A study showed that this design offers cyclists only an 11% improvement in safety over an uncontrolled junction so it should be no surprise to us that roundabouts of that design also quite often appear amongst the more dangerous locations for cyclists in the Netherlands.

The less safe roundabout design was first trialed in Enschede so perhaps it shouldn't be too surprising that Enschede's most dangerous junction for cyclists happens to be one of those roundabouts, where six cyclists were injured. Enschede's second most dangerous junction is an uncontrolled junction which injured five cyclists.

Heading west, the city of Deventer also uses the less safe roundabout design and there too the most dangerous junction is a roundabout. As in Enschede, their second most dangerous is uncontrolled.

Another city to use the less safe roundabout design is 's-Hertogenbosch. In this city, a roundabout which injured five cyclists and three moped riders is the most dangerous junction and second place is taken by another roundabout which injured another three cyclists and a moped rider.

Zwolle's most dangerous junction is another of those unsafe roundabouts, which injured seven cyclists, while second place is taken by an uncontrolled junction.

I have not been able to find a single example which where a roundabout of the safer design stands out.

Shared Space
The Laweiplein Shared Space in
Drachten, Many claims are made for a
low accident rate but it's the second
most dangerous place in the city.
Claims have often been made about improvements in safety in Drachten due to Shared Space junction designs. As it turns out, the most dangerous location in this small city is not a shared space, but another of those unsafe roundabouts, where four cyclists were injured and one cyclist died. However the second most dangerous place in the city, with three cyclists and a moped rider being injured, is a location which I've covered before: the Laweiplein Shared Space "squareabout" which has been central to many claims of improved safety in the past. Far from improving the safety of Drachten for cyclists, the Laweiplein is one of the main causes of danger.

Shared Space designs do not have a good record for cyclist and pedestrian safety nor for inclusiveness.

Traffic light junctions:
The most dangerous junctions in both Amsterdam and Rotterdam are large and traffic light junctions with an outdated appearance which include tram tracks and which have two-stage turns. These junctions, which injured ten and eight cyclists respectively, have similarities with those which have proven to be lethal in Copenhagen.

On the other hand, traffic light junction designs which remove all conflict from the junction don't stand out in these statistics.

Detail from the most dangerous Amsterdam junction. The cyclist on the right of the picture is perhaps trying to reach the left turn box just left of the car. Poor infrastructure design results in cyclists seeing a reason to position themselves like this.
Dangerous streets
While it's relatively easy to find the individual most dangerous locations, it's more difficult to identify streets with an obvious line of injuries along them. I'll give just three examples from Assen and Groningen:
Weiersstraat in Assen. A location with a poor layout of on-road cycle-lanes causing conflict between all modes. I criticized this earlier this year (maps and data from the excellent ongelluken kaart).

Gedempte Zuiderdiep in Groningen. While buses get their own lane, cycles and cars are made to "share". An unpleasant street layout which uses cyclists as rolling traffic calming devices: resulting in a row of cyclist injuries along it.

Nieuwe Ebbingestraat in Groningen. There's plenty of width here for proper cycling infrastructure and this could be a pleasant road to cycle down, but none is provided. The street has much through motor traffic and many cyclists are injured both by moving cars and by parked cars, e.g. through dooring. Cyclists are again used as traffic calming devices here and the result is another string of injuries as seen above. Update 2016: Remarkably, Groningen now sees this design as inspirational and wants to build more streets with this same dangerous design.

Video of Nieuwe Ebbingestraat: Groningen's most dangerous street for cyclists. The problems may look minor compared with some other places, but note now they arise for the same reasons as elsewhere: No or poor cycling infrastructure such as narrow cycle-lanes, advanced stop (bike) boxes leading to close over-takes, door zone cycling etc.

Whole suburbs can be made safe
Assen suburb of Kloosterveen.
Population 10000. No yellow:
No cyclist injuries recorded.
For the last 40 years or so, Dutch suburbs have been designed to have few connections by car and to discourage high speed driving. The result is that cyclists and pedestrian injuries are very rare within these suburbs.

We live in the Assen suburb of Pittelo, first to be designed along these principles and built between 1970 and 1975. There are many ways out of the suburb in all directions by bike, but just two exits by car, both of which go to the ring-road. As a result, there is no through traffic and there are no recorded cycling injuries over the last six years. The same characteristics are true of the very newest suburb of Assen, Kloosterveen, which also has zero cyclist injuries recorded.

Groningen suburb Vinkhuizen.
Population 11000. Cyclists
injured in several locations.
The Groningen suburb of Vinkhuizen has about the same population as Kloosterveen however it was built at the very end of the 1960s/beginning of the 1970s and came just too early to benefit from the new ideas about not allowing through traffic. This suburb has many more exits by car and allows through traffic both to an industrial area and another suburb. Many locations within Vinkhuizen have proven to be dangerous for cyclists, including both the roundabouts in this suburb, one of which is listed above as the second most dangerous junction in Groningen. Note that Kloosterveen has twice as many roundabouts as Vinkhuizen and that they appear on the busiest roads within that suburb. But these are all of the safer design and no cyclists have been injured at them.

Note that the most dangerous junction in Assen is also situated in an older suburban area, on a road which allows through traffic.

What is the role of infrastructure ?
Infrastructure of any type should be designed to serve the people using it. That may seem self evident, but time and time again we see infrastructure which is not designed in this way. e.g. streets in cities with a lot of cycling which ignore cyclists (as in the example shown in Groningen above, these can be dangerous). Infrastructure should be designed to accommodate the pattern of use which it is expected to receive, and should also be designed to take into account that human error is inevitable and therefore to reduce the likely consequences of error.

What improves safety ?
It is not enough to put a lower speed limit on a dangerous road design. 30 km/h speed limits are more common in the Netherlands than in any other nation: a third of the whole road network has this speed limit or lower. Lower speeds help a little, but note that many of the examples above are in low speed limit areas. It has long been recognized that lower speed limits do not ensure safety of their own accord.

Infrastructure which relies upon perfect driver and cyclist behaviour for their safety can also not create a perfectly safe result. Human beings make mistakes. "Accidents" are inevitable. Create situations in which there are too many things to do at once, especially where drivers' heads have to swivel repeatedly to look in several directions for things to respond, and you've created a situation where accidents will happen.

Uncontrolled junctions are unsafe compared with controlled junctions, but of course it's not practical to add traffic lights everywhere. Roundabouts of the "with priority" design are somewhat safer than uncontrolled junctions for drivers, but offer only an 11% improvement in safety for cyclists so these are not a solution to the problem.

The genuinely safe roundabout designs and safe traffic light junction designs lead to real improvements if they replace a more dangerous junction design, but of course they won't fit everywhere either.

Luckily, these larger and more expensive designs of junction are not required everywhere. In fact, they're only required where there are motor vehicles. Without the added danger of motor vehicles, especially of through traffic, uncontrolled junctions can have perfect safety records too: The safe suburbs discussed above (Kloosterveen and Pittelo) both have many uncontrolled junctions. Neither of these suburbs includes any traffic light junctions and only one of them includes roundabouts (four roundabouts of the safe design in Kloosterveen).

Almost all significant danger to cyclists comes from motor vehicles and therefore restricting car, truck and bus access from where bicycles need to go is the most effective way to improve cyclist safety.

  1. Residential streets should never be through routes by motor vehicle.
  2. City centre streets can largely be closed to car access and should also not operate as through routes.
  3. Main routes between these places which must be shared with drivers need good quality cycle paths and well designed junctions.
  4. Routes from which motor vehicles have been excluded have less need for such infrastructure because they will already not have the same clusters of injuries along them as appear along roads where cyclists and drivers "share" the same infrastructure.
  5. Data which exists shouldn't be ignored. We can tell from a map of where injuries have occurred where intervention is required.
  6. New isn't always better. Wide pavements do not improve conditions for for cycling. Unfortunately, such designs are now quite common around the world, including in the Netherlands.
  7. Shared Space where cars and bikes are mixed is not a success for improving safety.
  8. Paths shared between cyclists and pedestrians lead to conflict.

The most effective way to improve safety of cyclists is the same as it's always been: remove motor vehicles from where cyclists need to be and give cyclists their own space This not only improves safety for cyclists but also enables improvements in efficiency for cycling.

Sometimes it's necessary to build new roads or new bridges for cars in order to improve conditions for cyclists.

Study Tour
Study Tours. Click for booking information.
Since 2006 we've demonstrated the difference between safe and unsafe infrastructure on study tours of Dutch cycling infrastructure. We offer independent advice. See many examples in real life.

Update: Dutch Drivers
A news item published two days after this blog post includes the interesting fact that over 21000 speeding fines were handed out to drivers in Assen last year, who paid over €1.2M in fines as a result.

As I pointed out many times before, including above, Dutch driver behaviour is not different to that of drivers elsewhere. Safety for cyclists in the Netherlands comes primarily through good infrastructure design, not better driving.


Restlesstablet123 said...

When you mentioned simultaneous green is safer than other junctions did you mean subjectively safer? A protected intersection can also prohibit conflicts (of course some people will run red lights in both cases, which will be the most likely source of problems I think), but has the disadvantage of scaring people away, because heavy motor traffic going next to you even if you know they are prohibited from conflicting with you (on a well designed protected intersection). It can also have higher waiting times to go left, which means people are closer to motor vehicles for longer in some cases.

David Hembrow said...

Restlesstablet: Please follow the links to find out more. Simultaneous Green junctions are not only subjectively safe and convenient. They also have a particularly good safety record with regard to accident stats.

Greg said...

Based on a 2014 California law adding separated cycle tracks to the state highway design manual, Caltrans has until January 2016 to publish design standards for the new facilities. Unfortunately, it doesn't sound like they have any plans to add protected intersections to the standard.

David Hembrow said...

Greg: That's unfortunate. But if they do show signs of wanting to build safer intersections please try to get them to come over here and find out what real Dutch intersections look like before designing and building anything. Dut to misunderstandings, the current batch of "protected intersections" in the US fall a long way short of real Dutch infrastructure, not only with details of the design, but important parts missed out (such as ensuring priority for cyclists with traffic lights) and with the wrong ideas being used in the wrong places (i.e. solutions suitable for very small junctions being scaled up to huge busy junctions in an inappropriate manner).

Matt said...

Hi David, looks almost British!!

It shows that there is space by using some of the pavement, or making it one way for cars, or both. Problems have solutions, and I was especially 'heartened' if you get my drift, that Dutch drivers frequently get speeding tickets, 1) because the law is being upheld and 2) they are no better or worse than British drivers, so this is more ammo against 'sharing the road nicely' as advocated by Vincent Stops and his VC mates