Poor cycling infrastructure designs struggle when it comes to allowing cyclists to make turns across traffic (a left turn in continental Europe / USA) in a manner which is both convenient and safe. In some cases, designers simply don't really try and this results in such abominations as centre cycle lanes leading into advanced stop lines (bike boxes) on the ground. There are also examples of designs which are promoted quite hard but which don't really help people to cycle because they make turns inconvenient, dangerous or in some cases both inconvenient and deadly dangerous.
The new junction on the day it opened. The cycle-path widens
to nearly 4 metres in width to accommodate cyclists going
straight on as well as those turning left. Note traffic lights
for cyclists. The green for straight on is almost always lit.
This only goes red to allow cyclists to emerge from the right.
On the other hand, there are also good examples, though these are not necessarily so easy to find. Some designs improve both safety and convenience for cyclists. One solution for traffic lights which I'm particularly enthusiastic about because it has a very good track record is the simultaneous green junction, however there is no one design of junction which fits all locations and other good designs are possible.
This new junction demonstrates a very good way to design for asymmetric cycle traffic. In this case, almost all cycle traffic heads head straight on across the junction and they have a nearly full time green light. Only the relatively small number of cyclists who turn left are stopped by the traffic light in the video and this introduces only a short delay until it can stop all conflicting motor traffic and remove all danger from the left turn.
Crossing in the opposite direction is also convenient. Note that
right turning motor traffic is stopped when cyclists have a
green light and all straight on motor traffic is to the left of the
thick white line. There is no conflict in this direction either.
The old junction in this location featured on my blog in 2012. This already worked well, but it stopped cyclists heading straight on relatively frequently and did not allow for a left turn to be made by bicycle. The old junction was built on land and did not incorporate a bridge. The new bridge had to be built to enable re-opening a canal which was filled in decades ago and the new junction is on top of that bridge.
The Weiersbrug is one of six new bridges in Assen which began construction at the end of 2014. Five of those bridges are now complete and one remains to be built. I've been critical in the past of some aspects of the huge FlorijnAs project in Assen, but it has also brought improvements for cyclists in some locations, such as here.
Another view from another angle
This junction really does work very well for cyclists. The delays for a green light are minimal, and this partly is the result of the lights defaulting to red for everyone (cars, bikes, pedestrians) when there is little traffic and responding almost immediately to whoever comes along first. This video shows what it's like to go through this junction twice on a Sunday morning when there are few people about:
An older implementation of the same idea, with inadequate
lane sizes and not enough space to make the turn. This was recently removed from the area around Assen railway station.
Not a new idea, but a top class implementation
The idea of cyclists waiting to turn left at a traffic light in this way is not in itself new. However, this new junction brings a level of refinement which makes it comfortable to use. This new junction works far better for left turning cyclists than did the an older implementation of the same idea which was recently removed from the railway station area of Assen.
The junction shown in the video with a blue arrow showing the route taken by left turning cyclists in the video. While cyclists make this maneouvre or any other across the junction which could result in conflict with motor vehicles, red traffic lights hold motorists to remove the conflict.
Come and see
This new junction opened in May on the second day of a follow-up study tour. There is new cycling infrastructure to see every year in Assen and the programme changes each year to allow for what has changed. Future study tours, such as the tenth anniversary tour in September, will feature this junction amongst other pieces of new infrastructure.
Imagine if it were possible for cyclists to take their desire line across traffic light junctions, even riding diagonally if that the shortest path. Imagine if this was possible in complete safety because there were never any cars using the junction when cyclists used it. Imagine if cyclists' green traffic lights were twice as frequent as those for drivers so that average delays were shorter if you cycled. Imagine that all this was already reality...
For cyclists, the safest and most convenient design for traffic light junctions is the simultaneous green.
With this design, cyclists always make their maneuvre in one and directly. There are never inconvenient and unsafe two stage turns, never is there the possibility of being "hooked" by motor vehicles turning across a cycle lane between other traffic lanes, never do you have to merge with motor vehicles making the same or other maneuvres and there's never a requirement to find your way forwards to dubious safety of an advanced stop line or to make your way across several lanes before the junction to get into the correct lane to make a turn across traffic.
Simultaneous Green gives cyclists their own green phase during which they may travel in all directions at once, including diagonally, following their own desire line across the junction. While cyclists are crossing, all motor vehicles are held behind red lights. When motor vehicles are moving, all cyclists are held behind red (with the exception of often being able to make a safe right turn).
This video shows one of the largest simultaneous green junctions in action:
This is one of the largest simultaneous green junctions in Groningen. As the video starts, we are about to cross ten lanes of traffic, diagonally. This is maximally convenient for cycling. Note also it takes just 20 seconds for us to cross and clear the junction. That's the time required for everyone to cross in all directions by bicycle in the world's top cycling city at a very large junction. Note also how easy emergency access through the city is aided by the bus lanes
It's obviously convenient. Is it really safe ?
There have been no incidents with
bikes here at all. Note how west and
east sides of the junction are very
different. No single solution fits
all existing streets.
Because these junctions remove cars from the road when cyclists are riding on them, the main danger to cyclists is removed. The result is that cyclists crossing simultaneous green junctions are rarely involved in collisions and even more rarely injured. These are extraordinarily safe junctions for cyclists. Between 2007 and 2012 Only one incident involving a bicycle was reported at all of the simultaneous green junctions in Assen added together and that incident didn't result in an injury.
People sometimes wonder how it is that cyclists don't collide with one another while crossing diagonally. There are actually good reasons for this. The whole area of the crossing can be used and peoples' desire lines don't cross at the same point in time.
It's not mere opinion which leads me to call these safe junctions. There are figures to support this and they show a stark contrast between the impressive safety record of simultaneous green junctions, of which there are many in Assen and Groningen amongst other Dutch towns but at which cyclist injuries are virtually unknown, and the relatively bad safety figures seen at shared space and other less well engineered junction designs. What's more, simultaneous green junctions are also subjectively safe. Who doesn't feel safe to cycle when there are no cars moving ? The result is that this type of junction empowers vulnerable road users rather than dis-empowering them.
The designs of different sides of
junctions like this vary enormously
depending on the road that they
are connected with. The principle
scales to all sizes and works with
mixed arrangements like this. This
is the junction at which there was a
single minor incident reported by
a cyclist in 2008. An incident which
did not result in an injury.
Why isn't everyone asking for this design ?
I've been writing about the benefits of simultaneous green for many years now and we have been demonstrated these junctions to hundreds of people on our study tours but somehow it's not easy to get the superiority of this design over others through to people.
This is a superior way of using junctions but it suffers from a lack of familiarity.
There's no one size fits all design that people can take away. This is not about We show a variety of different sizes of simultaneous green junction but we find that people still find it hard to understand how this scales to all sizes of junctions. Some think it takes a lot of space or takes too much time from other modes. None of these things is true. Simultaneous green principles apply well at all sizes of junctions and we've found that in all cases it works extremely well. What's more, all the junctions we're aware of have great safety records.
How much impact on other modes ?
There also appears to be a perception that safety and convenience for cyclists has been achieved by making the junction inconvenient for other modes. While it's true that these benefits are the result of cyclists having the entire junction to themselves when they cross, it should be remembered that cyclists travelling in all directions at once make the very best use of the space while they do so. Because of this, even very large junctions can be cleared by big groups of cyclists from all directions at once in a very short time. After they're clear, there are no cyclists left on the road who could in any way inconvenience other modes. What's more, drivers don't even have to do so much as cross an empty advanced stop line because there is not reason for there to be an advanced stop line and they do not have to negotiate road space with cyclists either on the lead up to the junction, while crossing or at the other side. For all these reasons, simultaneous green leads to very efficient use of the junction.
This design can give cycling a competitive advantage
Because cyclists' light are completely independent of those used by drivers, more advanced possibilities are on offer than are possible merely by synchronizing with the cycle used for cars. It is often the case that cyclists are given more than one green phase during each cycle of the lights, meaning that the average delay by bike is half that by car. When simultaneous green is combined with being able to make a safe right turn against a red light, which it very often is, the average delay for cyclists, taking all desired directions into account, is reduced even further. This helps to encourage cycling, which itself improves journey times for motorists.
Examples of scaling to all sizes of junctions
While the video above shows one of the very largest simultaneous green junctions, where you ride straight over or diagonally across a ten lane road in Groningen in one movement, the following photos show how the design scales down from this very large junction to work just as effectively at extremely small junctions. Note that each of these examples is of a different design. There is no one-size-fits-all style of concrete buffer required to separate bikes from cars in a simultaneous green junction. No single easily explained design. The principles are what are important, not an exact pattern which won't necessarily fit into your city:
The same junction as shown in the video above. There are ten lanes here. Four in each direction for general traffic and an additional two lanes for buses only in the middle of the car lanes. From the cycle-path on which we approach you can turn left (diagonally) or go straight onwards. Note the right turn lane for cyclists, which takes cyclists around the corner entirely separately from the road and does not require stopping at a red light at all. There is more about this junction in a much older blog post.
Another view of the same junction from a different angle, in which people can be seen riding in all possible directions. Note that there is no concrete kerb on the corner because this would be in the way. Everyone on a bike is following their own desire line while all motor traffic is stopped. This removal of the main source of danger at the junction is what makes simultaneous green so safe. This may look lik a composite photo because there are bikes all over the place, but it's not. This is just a still image of the same crossing as shown in the video at the top during a different green phase. Cyclists negotiate routes on simultaneous green junctions, making maximum use of the available space. This is why it's such an efficient design
A wide bidirectional cycle-path leading up to a medium sized simultaneous green junction. This is the same junction for which I showed the accident record above. Right turns, and also left from a position to the right of the photo, are possible here against a red light simply by riding around the corner on the cycle-path.
The same junction from a different angle. The narrower road leading up to the junction from this direction has just an on-road cycle-lane, but safety and convenience are enhanced by a kerb for a short distance before the junction which also assists integration with a simultaneous green junction. The blue sign gives specific notice that right turns are allowed against a red light.
The same junction again, this time from a third angle. In this case, a 2.5 m wide single direction cycle-path leads up to the junction. The corner of this junction which appears on the far left of the photo is that which featured in the first photo. The blue sign shows that right turn on red is allowed here.
A smaller junction and a narrower cycle-path which still allows bidirectional use by cyclists. Right turn on red is accomplished by turning right on the cycle path which goes around the corner to the right just off the edge of the photo.
On the other side of the same road, facing the last photo. This is a very narrow one-way street for cars which has on-road cycle-lanesto allow bidirectional use by bike. A short section of cycle-path is used to provide a waiting area for bikes. Those who wish to make a left / diagonal turn use the left half of the cycle-path. Those going straight on use the right half. Simultaneous green scales easily to small junctions like this. Because cyclists must cross the road to head to the right, right turn on red is not possible in this instance.
At the end of a feeder street in a residential area which has no specific cycle provision at all, this bridge is wide enough to provide a small length of cycle-path which provides safe access and a waiting area for cyclists using the simultaneous green. The cycle-path on the far side of the road is bidirectional so we cross the road to turn either left or right and in both cases cross the road first. In this case, right turn on red is not possible.
A view in the opposite direction from the previous photo. A low traffic road has a short length of on-road cycle-lane which leads into the simultaneous green junction. Right turn on red is possible here simply by joining the cycle-path heading left-right across the photo. A different view of this junction can be seen in an older blog post
The design works even at extremely assymetrical junctions such as this. In this case, we're on the bidirectional cycle-path which runs left to right through the previous photo. When the light goes green, cyclists heading in both directions on this cycle-path may turn across to the other side of the canal (right in this picture), go straight on towards each other remaining on the cycle-path, or turn down the small road in the previous photo (left in this picture). A view of the same cycle-path at the same junction but taken in the opposite direction can be seen in an older blog post
Busting myths
I hope with this blog post to have busted myths about Simultaneous Green being difficult to implement or only being suitable for large junctions. In fact, it works extremely well at all sizes of junction from the very small to the very large.
What's worse ?
Almost any other design of traffic light junction creates more problems and danger for cyclists than does this, yet it is these other ideas which are given prominence in design guidelines around the world.
One of the junctions shown
above in Assen looked like
this at the start of 2007.
The "protected intersection"
design which some people
are still pushing.
The much pushed but somewhat mythical "standard Dutch junction" is not a terrible solution but it is less safe and less convenient than simultaneous green.
Copenhagen Left type junctions are not only inconvenient because they require cyclists to stop twice and divert from their desire line to make a turn across traffic but they are lethal in their home country so likely to be lethal in yours too.
Advanced Stop Lines simply don't provide any real protection for cyclists at all and centre of the road cycle lanes which are sometimes used to provide a way to turn across traffic at ASLs encourage cyclists and drivers to cross each others' paths.
Light controlled pedestrian crossings
shown in blue on a crossing in
Groningen. Possible directions by
bike from one corner shown in red.
The zebra crossings give pedestrians
priority over cyclists but in most cases
the pedestrian green light does not
not light at the same time as that for
cyclists.
Pedestrians must also be accommodated by any junction design.
It's not practical to allow pedestrians to walk diagonally across at junction at the same time as cyclists are doing the same as this causes conflict. However, provided that pedestrian crossings are outside of the cycle crossings, as shown in the picture on the right, pedestrians can cross in all directions other than diagonal at the same time as cyclists use the simultaneous green crossing and without any conflict at all.
The time taken for a cyclist to cross a wide road is considerably less than that taken by a pedestrian so there is no extra impact on traffic light cycle times from the point of view of motorized modes due to allowing simultaneous green at the same time as pedestrians are allowed to cross.
In Assen, conflict has been removed by
a further step. Pedestrian crossings are
completely outside the cycle crossings,
meaning that there is no conflict at all.
Pedestrians therefore don't need to rely
upon cyclists stopping for zebra
crossings on cycle-paths
In practice it is necessary at wide junctions to provide central reservations with additional push buttons to operate the pedestrian crossing. This is required to accommodate people who walk slowly. That can also be achieved without any conflict though it's never very pleasant to be in the middle of a road. It should never be necessary for a cyclist to cross any road in more than one stage, even if riding diagonally, even if crossing ten lanes of traffic as shown in the video above, because cyclist speeds are higher than pedestrian speeds.
Groningen's simultaneous green crossings use zebra crossings across the cycle-path in an attempt to give pedestrians priority over cyclists. Unfortunately, they placed the pedestrian crossings in front of the cyclist stop lines. The problem with this design is that it can result in a pedestrian reaching the far side of the road just as cyclists are given a green. Cyclists are therefore delayed entering the junction and may be tempted to jump a red light. This potentially converts a minor bike-pedestrian conflict into a more serious bike-car conflict. In Assen a superior design is used which places the pedestrian crossings completely outside the cycle crossings. Therefore cyclists can always go without delay when they have a green light, and pedestrians never clash with cyclists.
Choose Simultaneous Green
Simultaneous Green is by far the most convenient design of traffic light junctions for cyclists. What can be more convenient than following your desire line across a junction ? This is also now an extensively tested solution which has proven to be extremely safe - this is objectively shown by viewing the online map of collisions. This junction is more convenient and safer than the mythical "standard Dutch junction", much more convenient and very much safer than the proven lethal two stage turn design and it also has also proven to be far safer for cyclists than shared space junctions even when those are on a smaller scale, catering for a much smaller number of motor vehicles.
Dutch signage for
simultaneous green.
Given the advantages and the flexibility of simultaneous green, this is the junction design which cycling organisations the world over should be trying to emulate. It may take some changes to your local laws to allow the required signage and to change to way in which traffic lights are sequenced, but these are human constructs which are changed all the time. The advantages of Simultaneous Green are such that it is truly worth campaigning for.
It's not new (I've been writing about it for six years) and it's not an unproven idea. It's popular with cyclists because of its convenience and has proven to be safe. Enough time has passed that had campaigning for this junction design started when I first wrote about it, your laws could already have been changed to accommodate this style of junction. Get campaigning!
In Assen and other Dutch cities, traffic lights are used to control motor vehicles. Cyclists do not require traffic lights on their own but only on some occasions when they come into the same junctions as motorists. Assen provides an excellent example of how to minimise interactions between cyclists and drivers. The city also provides an excellent example of how few interactions with traffic lights there can be for cyclists where the infrastructure is well designed.
Every traffic light in Assen. Note how the centre of the city and residential areas have no traffic lights at all. Most traffic lights are on main routes for cars, not for bikes. Some spots show more than one set of lights.
Every Traffic Light in Assen
There are many misconceptions about how cyclists use traffic lights in the Netherlands. In order to try to explain how cyclists really use traffic lights in the Netherlands, this blog post shows every traffic light in Assen and explains what interactions, if any, cyclists have with each example.
You will see from the map above that there are few traffic lights in this city and those which exist are almost entirely on the main routes for motor vehicles. Residential areas have many junctions but no traffic lights in them at all. The very centre of the city also has no traffic lights at all. Many journeys by bicycle can be made without interacting with traffic lights. It was a specific goal when building the new suburb of Kloosterveen outside of the city on the west, that new residents would be able to reach the city centre by bicycle without meeting any traffic lights along the way. Traffic lights do occur on the motor vehicle route from the new suburb to the city.
Traffic lights are to be found where there are most cars, not where there are most bicycles. In many cases, due to the unravelling of driving routes from cycling routes, these traffic lights are not used by cyclists at all so never cause any inconvenience. Most cycle journeys do not involve repeatedly stopping at traffic lights.
Traffic lights controlled crossing are also provided to help cyclists to make convenient and safe crossings of major roads.
In total there are 28 locations with traffic lights in Assen, numbered 1-26 below (with "a" and "b" used where there are two too close together to separate on the map above). They are classified as below. Between these 28 traffic light locations, there have been 11 cyclist injuries over six years:
Pedestrian and cyclist crossings (1, 6, 13)
These lights are provided in order to improve cyclist safety when crossing potentially busy roads. While cyclists may find a red light when they reach one of these crossings, they never have to wait more than eight seconds (it's often less) before motor traffic is stopped and the light goes green for crossing. Junction one in a west-east direction is shown in this video:
There is also a traffic light at this location which occasionally stops both cyclists and motorists travelling north-south if a bus goes along the bus-road parallel with this cycle-path. However this defaults to green for both bikes and cars and provides only a very rare and very brief inconvenience.
Earlier videos demonstrate both junctions six and 13. These are just as convenient for cyclists as the crossing illustrated in the video above. One cyclist injury in Assen occurred at a crossing like this.
Simultaneous Green for bikes (9, 14a, 22, 23)
In Assen, traffic lights prioritize cycling. One of the ways in which this is done is the use of simultaneous green lights on which cyclists ride in any direction, including diagonally, across the junction with no interaction whatsoever with motor vehicles. These are combined with being able to turn right against a red light. Junction 22 is a mid-sized simultaneous green junction which has featured several times on this blog but this principle can also be used successfully on smaller and large junctions.
Where cyclists use traffic light junctions, the simultaneous green layout is the most convenient and safe way to do this. No cyclists have been injured at simultaneous green traffic light junctions in Assen.
Cyclists using the secondary W-E route south of the canal use
a simultaneous green junction. Those using the primary route
north of the canal have a bicycle road with no traffic lights
Junction nine is interesting because west-east (the most common direction of travel at this location) cyclists will only have their journeys interrupted by this traffic light if they are on the southern side of the canal, which is a secondary route. The North side of the canal is a bicycle road which offers the primary route for cyclists. It provides a direct nearly-car-free route to the city centre with no delays due to traffic lights for people who live on the west of Assen.
The main route for motor vehicles is also west-east in this location. The north-south route connects to residential feeder streets with lower traffic levels.
Default to Green for bikes (3, 4a, 17)
Three junctions in Assen default to a green signal for cycling and only make cyclists stop if a driver has triggered a sensor. The intention is that it is normally the case that you ride over these junctions without stopping.
There are videos which demonstrate both junction 3 and junction 17. No cyclists have been injured at default to green crossings.
Traffic light junctions which only exist for motor vehicles (7, 14b, 16, 18, 19, 26)
These junctions simply don't exist so far as cyclists are concerned. They regulate motor traffic along busy roads which provide routes for motor vehicles completely unravelled from cycling routes.
Junctions 16 and 18 don't apply to cyclists at all even though they are in line with junction 17 which defaults to green for bikes. You can see them in this video.
Junction 19. On the other side of these traffic lights is the motorway. The only reason why you would reach this point on a bicycle is if you were that sort of vehicular cyclist who is determined to ride on motorways. There are far better routes North from Assen by bike than this one and they have fewer traffic lights too. While few cyclists use this junction, one person on a bike was injured here. View Larger Map
Traffic lights with only incidental interaction with cyclists (12, 25)
To access the hospital from the city
centre we follow the cycle path in
red directly to cycle parking by the front door. It's only necessary to cross
using the lights from the South
Junction 25, at the hospital entrance, is a major junction for motor vehicles combined with a simple crossing for bikes.
Major road junctions with cycle crossings on some sides of the roads (2, 4b, 5, 8, 10, 11, 15a, 15b, 20)
Junction 15a (15b is nearly identical)
A major junction for cars. Delays are
short for cyclists and there is time to
cross all six lanes without stopping
in the middle.
These junctions are nearly invisible to cyclists because they serve traffic on the ring road and in industrial areas and cyclists routes are mostly unravelled from them. When we do have to ride near these roads we often ride alongside them and do not cross. Nevertheless, when we do cross at these points, the delay to get a green light for bikes is not excessive: generally less than 30 seconds.
Junctions 15a and 15b are both very large and very busy. Both of these junctions have injured cyclists (five in total at these two junctions).
Junction five. In the video below, I ride
from South to North here. Pink/red
show cycle-paths/my route.
There is never a requirement for cyclists to stop in the middle of the road and operate a second traffic light in Assen, no matter how many lanes are crossed.
Junction five is illustrated in the video below. This video also demonstrates the junction timing. Note how the delay before crossing is not long (these cyclists reached the junction only slightly ahead of me) and how when cyclists are given a green light, it stays green long enough that a large group can cross this major junction (in this case five lanes of traffic) in one:
The blue bridge which the cyclists go under carries only cars, but it was built for the benefit of cyclists so that there did not need to be a traffic light on the cycle-route. Find out more about this.
Where there is a requirement for cyclists to be able to turn right, these junctions provide for safe right turns when there is a red light (a privilege which motorists don't enjoy in the Netherlands). It is very rare that anyone should have to ride across two arms of these junctions as part of one manoeuvre because in each case, another route exists.
Junction eight is really only a crossing so far as cyclists are concerned. It featured in a video showing children on a school trip. Oldest junctions, soon to be replaced (21, 24)
Outside the railway station. Cycle
routes (not all are cycle-paths)
highlighted. This is being changed.
Junction 24 almost made it into the major junctions category. It doesn't cause many problems for cyclists, but it does represent an older attempt at providing cycling infrastructure and the work has already started on replacing that junction altogether within the next few years.
Junction 21 is an interesting example. It's the least satisfactory traffic light junction in Assen and because it's right next to the railway station, it's one of the first pieces of infrastructure that people see when they visit the city.
This is the closest example that we have of the sort of thing that seems to come to mind to many people outside this country if they try to think of what a typical Dutch traffic light junction looks like. It's actually one of the oldest pieces of infrastructure in this city, dating back to 1989 when the existing railway station was built. Two cyclists were injured at this junction.
This junction dates from the 1980s. It's the most awkward traffic light junction for cyclists in Assen and often requires people to make a two-stage turn. Don't take inspiration from older infrastructure like this. It is soon to be removed.
In the near future, through motor traffic
will be underground while cyclists
stay at ground level. No traffic lights
will be required so no more delays or
multi-stage turns for cyclists.
The railway station as well as the junction are to be replaced in the next few years and the traffic lights are going away. Most of the problem with traffic here is caused by through motor traffic travelling North-South. This traffic will use a tunnel in future. The result is that the junction outside the railway station can be transformed into a far more pleasant space which will provide for access to the station by car but should not be dominated by motor vehicles.
When this work is complete, this last of these older style traffic-light junctions in Assen will be gone. No traffic-lights will be required here once the main road is underground, greatly increasing convenience for cycling. The cycle-route between the railway station and the centre of the city will no longer have any traffic lights on it.
Places where there used to be traffic lights, but they're no longer needed
The first traffic lights installed in Assen were here. They
are no longer needed because this is now nearly car free
The idea of changing places so that motor vehicles don't dominate is not new to Assen.
Like all city centre streets in Assen, and across the Netherlands, the streets in the photo on the right was dominated by motor vehicles in the mid 20th century. This was the busiest street in Assen and the first traffic lights in the city were installed here in order to deal with the traffic.
However, the city centre streets are now either completely car free or now nearly car free. They can still be used as a through route by bike but not by car. The removal of through motor vehicles meant that the traffic lights were no longer needed at this location or several others in the city centre, making cycling more convenient.
How well does this combination of junctions work ?
Every junction in Assen, whether with traffic lights or otherwise, can be used safely by every cyclist in Assen. What's more, this infrastructure is not only safe but also convenient. Children, older people, those with disabilities all use the same infrastructure as confident adults and fast cyclists because the same infrastructure works best for everyone in terms of both safety and convenience. No-one is expected to choose between a safe route and a convenient route.
Of Assen's 28 traffic lights, six simply don't "exist" so far as cyclists are concerned. Two more of the local traffic lights have only incidental influence on cyclists. Three are provided specifically to create safe crossing points for cyclists and three more default to green for bikes so rarely cause slowing for cyclists.
An underpass built in the 1970s
allows cyclists from the east of the
city to pass under three railway lines
and two roads, and avoid the old
set of traffic lights by the station.
Only half the traffic lights, fourteen sets, remain to be considered. Four of these are of the excellent simultaneous green design which provides the best combination of both convenience and safety for cyclists. Nine are large junctions which we use rarely by bike but which are in any case safe and convenient if you should have to use them.
Just only junction is annoying to use - the old junction at the railway station which is soon to be removed and will no longer cause inconvenience. Even at this location, though, there are ways in which many people can completely avoid the delays caused by that junction. Infrastructure that we don't have. Lessons to be learnt
In no cases at all in Assen do we have cyclists on the road mixing with cars at a traffic light junction. There are also no cases where cycle-lanes lead cyclists between streams of moving vehicles. There is no location at which cyclists clash with motorists or have to turn across moving traffic at all. There are no advanced stop lines (bike boxes) used in Assen as these are inadequate to keep cyclists safe. There are no two stage turns and certainly no instances at all of the dangerous design in which cyclists are expected to share their straight on lane with that used by drivers turning right.
We also don't have any junctions of the type which have become known in some circles as a "standard Dutch junction" and this is a very good thing.
The junction closest in design to these that we have is the outdated example by the railway station which, as described above, is being removed. Yes, Assen is getting rid of junctions which look like that, not building more of them.
Badly designed junctions lead to inconvenience. They perhaps also result in a reduction in safety as people try to find more convenient ways to make turns across traffic without having to stop twice.
Unfortunately, the idea that there is such a standard traffic light junction design, that it looks something like this, and that it's something to emulate, has become popular. I've seen this idea pop up in many places. In this case, it's gone so far as to the other side of the world. It is precisely to help people to avoid making mistakes like this that we began running cycling infrastructure study tours way back in 2006. It's not too late for New Zealand's planners, or those from elsewhere, to avoid making expensive and dangerous mistakes. You can do a lot better than this. Contact us. Ask for advice. We're here to help you.
Huge junctions on small roads ?
We often have people ask us how the Dutch accommodate their "huge" junction designs on minor roads. The correct answer is, of course, that they don't do so because they do not need to.
Most junctions are not "huge". Most junctions are not busy. This is by design. Most junctions simply are not on the routes of through motor traffic. You'll note from the map at the top of this blog post that Assen simply doesn't have many traffic lights, and large parts of the city contain none. Many Dutch towns are like this.
In reality, at the most common design of junction in the Netherlands there is very nearly nothing at all to see. However, this is possible for reasons that go well beyond merely how you design traffic light junctions. Minor roads and residential streets have almost no motor traffic on them. To a far greater extent than other nations, the Netherlands has removed opportunities for rat-running.
Cycling routes are unravelled from driving routes to a great extent, making routes for cycling more direct and allowing cyclists to avoid traffic light junctions on their journeys. The only junction at which stopping is irritating is the older style junction at the railway station. This is from another age and we won't have to put up with it for much longer.
Summary
Readers may recall that when I visited London last year I was frustrated with the low speed and stop-start nature of cycling in that city. Many places in the world are like London in this regard. By contrast, it is rare that I stop for a traffic light when cycling in Assen and that is how it should be. Journeys by bicycle must be continuous and direct.
The material above is an example of what we cover on our study tours. We don't just talk about this, but we demonstrate the infrastructure so that participants can see for themselves how well it works. It's important to distinguish the features of modern Dutch infrastructure which make cycling accessibletoeveryone while also demonstrating where it falls down. Where the Netherlands has made mistakes, and where those mistakes have not yet been corrected, it's important that those things are recognized as what they are and do not form the basis for new designs elsewhere.
Assen provides an excellent example of how to do the right for cycling. This city has no university and therefore does not benefit from a large student population which would boost the cycling modal share regardless of infrastructure quality. Assen's higher than average modal share for a Dutch city (a higher cycling modal share than any city outside the Netherlands) has been achieved by investing in a very comprehensive network of better than average infrastructure which is constantly being improved.
On our tours we also visit Groningen, which for many years has been the top cycling city of the Netherlands. Different design choices were made in Groningen. There's also much older and less polished infrastructure than what we have in Assen. This gives an opportunity to compare how well different things work, to point out some errors and to show how older designs differ from modern designs.
We're independent. This means we are not supported by government or engineering companies. We can be entirely candid about what is good and what is less good. We have no commercial reason to push one idea over another, we only tell you what works.
Update 2015: Comparison with Bolton
A correspondent from Britain, Mitt Doot, understood the point I was getting at with this blog post and produced a map showing the positions of all 102 traffic lights in Bolton, a city in the UK with about double the population of Assen:
Mitt writes: "It's really revealing of how endemic Britain's traffic problem is when a town of a similar size to Assen needs 102 signalized junctions in order to 'safely' function. And let's not forget that every single one allows both pedestrians and cyclists to travel through them, only the pedestrians (most of the time) get their own signal phase. Some of these junctions are enormous, multi-laned deathtraps, and cyclists are expected to ride over them nonetheless." and further "The blue line is the most direct route cyclists could take from Farnworth, in the south, to Astley Bridge, in the north. It involves 25 separate traffic light junctions, almost as many as every type of signalized junction in Assen combined, just to travel this 5 mile journey." You can read his entire comment below.
Another correspondent informs me that the blue line which has 25 traffic lights in a five mile distance is designated as a strategic cycle route. That does not make for efficient cycling. It seems the words are rather more impressive than the reality in this case.
Just like the traffic lights, all the roundabouts in Assen also work very well for cyclists. Read the older post "Every Roundabout in Assen".
This location, a large Simultaneous Green junction in Groningen, was chosen for this example because of its symmetry, making it easy to illustrate with arrows showing the routes that people take as they cross the junction. To simplify the diagram I have not shown the straight over routes by bike or the legal right turn against a red light routes. (Google map)
In Assen and Groningen we have many Simultaneous Green traffic light junctions. These offer the greatest safety and convenience for cyclists. Cyclists can at any time make a right turn without stopping even if there is a red light, while straight on and left turns are made with cyclists going in all directions at once, separated in both time and space from motor vehicle traffic (all directions for motor vehicles have red lights while cyclists have green), never having to make an inconvenient two-stage turn in order to cross traffic.
Simultaneous Green design for cyclists works at both small and large traffic light junctions. This junction has many lanes of motor traffic, all of which is stopped while cyclists cross in one swift, safe and convenient movement. Junctions like this can also cater for vast numbers of cyclists. Note how the cycle lanes on several sides of the junction have more than one lane to cope with busy traffic. The cycle-path in the bottom right corner is five metres wide and has two northbound lanes combined with a southbound lane.
I drew this diagram in order to illustrate a common misconception amongst people who have never seen a simultaneous green junction in reality. It is often imagined that there will be many collisions between cyclists at the centre of the junction. If hundreds of cyclists really did try to ride perpendicular to each other directly through the centre of this junction at the same time then there would indeed be collisions, but that is not the reality.
Cyclists travel through curves
The distance that A has travelled to
reach the potential conflict point is
much shorter than the distance B has
to travel to do the same. The result
is no conflict in reality.
Cyclists do not make sharp 45 degree or 90 degree turns. Rather, they travel through graceful curves because this is the only way to control a bicycle. All design for cyclists should be made with this knowledge in mind. Sharp angles have no place in cycling infrastructure because they cannot be followed by a cyclist without slowing down.
In the came of simultaneous green junctions, the arcs that cyclists travel through result in the potential conflict points not being reached all at once by all cyclists but in fact being spread through time and space from the point of view of any cyclist using the junction.
Consider cyclists A and B in the diagram. B has to ride considerably further than A to reach the same point. This means that for cyclists riding at similar speeds there simply is no conflict. He will in any case also expect to give way to A because the convention at these junctions is that everyone gives way to the right.
There is no kerb in the corner of a Simultaneous Green junction. Cyclists must be free to follow many parallel paths in order to make the junction efficient. Cyclists consume less of the traffic light green time than with a two stage turn.
What's more, this is a simplification. My arrows do not show the exact lines of cyclist. In fact, the arcs used by individual cyclists at junctions like this vary enormously. While each cyclist turning left will start and finish in roughly the same place, these arrows should really be much wider in the centre.
While the cycle traffic lights are green, the entire area of the road junction is open for cyclists to use optimally. Faster cyclists often overtake slower cyclists while crossing diagonally. Negotiation takes place in that one party sometimes speeds up a little while another slows down. It is also straightforward to take a wider arc and therefore to go behind someone coming from your right.
The larger the junction, the more parallel routes are possible and the more efficient Simultaneous Green becomes both for cyclists and for other traffic as well because their total red time will be shorter with a simultaneous green layout than if cyclists cannot ride parallel and are required instead to follow each other in straight lines and cross twice.
Success !
It's easy to pick up misconceptions from blogs,
photos and videos online. Simultaneous Green
junctions are demonstrated on our cycling infrastructure study tours.
Simultaneous Green junctions are extremely successful. They have very good safety records and scale to all different sizes of junctions.
