Driver behaviour is more effectively controlled by road layout than by signs or speed limits. In order for it to be safe to give cyclists priority at a crossing, the speed of cars on the road needs to be controlled and traffic volumes need to be low. The junction needs to be designed such that it gives obvious visual priority to cyclists, and sight lines need to be good enough that drivers and cyclists can see each other and respond accordingly. This is not the same concept as "making eye contact". If people driving and cycling are surprised by the other party because they cannot see them in time then they are less likely to be able to respond safely.
residential streets. Three collisions with cyclists occurred over the 2007-2012 period at the second example, one of which caused an injury.
Curve radii and approach visibility
The recommendation of the CROW Design Manual for Bicycle Traffic for curve radii is particularly relevant to cycle priority crossings. The manual says that on curves with below 5 m radius, "cycling speed drops below 12 km/h and the cyclist has to work hard to remain upright" and suggests appropriate curve radii as follows:
- cycle connections that form part of the basic network should have a radius of greater than 10 m, geared to a design speed of 20 km/h;
- cycle routes and main cycle routes should have a radius of greater than 20 m, geared to a design speed of 30 km/h
|CROW recommended visibility at crossings by road width (crossing distance) and speed.|
All the roads shown in the above examples are under 7 m in width and in all those cases there is a 30 km/h speed limit so sight lines of about 50 m in length are required. All three examples include additional measures to control speed. In the first example, the posted speed limit and additional measures are adequate for a 50 m sight line. In the second example they are marginal (though helped enormously by the curve in the cycle-path which places cyclists in a more visible position and the curve in the road which slows drivers). The third example does not meet the requirements because the speed of cars is excessive and the sight-lines are not long enough.
Related: Note that it has been understood for many years in the Netherlands that posting a lower speed limit is not enough to ensure lower speeds.
Difficult to retrofit
It is very difficult to successfully retrofit crossings of this type because existing streets are often too straight, existing paths often not visible enough. While cycle priority crossings are fairly unusual in the Netherlands, retro-fitted cycle priority crossings are even more rare. All the examples of priority junctions in Assen were designed as integral parts of the road design. Those used as examples in the video and images above date from when those parts of Assen were designed and built in the late 1970s through to the 1980s.
Cycle priority is not the same as pedestrian priority
People sometimes ask why cyclists are not given permission to cross with priority on all pedestrian priority (zebra) crossings. There are good reasons why this should not be so. In many locations, it would be difficult for a cyclist to be The risk of a cyclist emerging quickly from behind a building or because there are inadequate sight lines. Cyclists are much faster than pedestrians and they require space in order to make a turn.
|At a very large busy junction, this example joining the 70 km/h ring road to a 50 km/h main route out of the city, neither cyclists nor pedestrians are given priority over motor traffic in any direction. On a road like this with many lanes of traffic, higher speeds and much to look out for it would be dangerous to give priority to cyclists or pedestrians. This junction is too large and busy to be a "protected intersection". While it could have seen implementation of a simultaneous green junction, instead there is a more conventional traffic light junction here next to which cycle path green lights are synchronized with motor vehicle red lights where conflicts would otherwise occur. Priority can be given for cyclists and pedestrians by other means. In other locations in Assen this is done by use of tunnels and very quick reacting light controlled crossings. Two cyclists were injured here. One due to a single sided collision with street furniture, the other due to ignoring a red light.|
A possible solution which people sometimes think of to the problem of turning across traffic is the hook turn. We have precisely one example of this in Assen. It's a relic from the past which has somehow survived on a quiet residential street and it's shown in the photo below. Note that the hook starts with a cycle-path in the top right hand corner of the image and continues more than 60 metres to the junction which it serves in order that it could provide a gradual enough transition for cyclists. The crossing is then assisted by a large raised table. Despite all of this, it's actually quite awkward to use. It perhaps made a little more sense decades ago when this was a busier route, but it certainly doesn't help in this situation now. I don't recommend this type of infrastructure.
|A generously proportioned 60 metre long hook turn assisted by a raised table. But it's still awkward to use.|
The Alternative Department of Transport blog recently coined the phrase "visual priority" to refer to where priority at a crossing is indicated by the design of the street and not merely by signs. The red surfacing continuing through each of the junctions shown in the video at the top of this blog post is a good example. I like this term, it's concise and obvious, so I have used it too. Most examples of crossings in the Netherlands benefit from good visual priority. Of course, good visual priority is only one factor. In itself it is no guarantee of success. As you will see from the video, the third example of a junction with a short raised table which coincides only with the crossing itself is not successful at slowing cars even though the visual priority is good. Junctions must also encourage safe behaviour by other means, such as use of bends on roads and level changes using a raised tables to slow drivers, bends on cycle-paths to improve sight lines, and we must of course realise that there is no one-size-fits-all solution. The majority of junctions are not suitable for a cycle priority treatment for reasons of sight-line or traffic speeds and volumes.
Real examples in real-life usage
Real examples in real-life usage
|It's not possible to completely understand infrastructure like this from reading blog posts and watching youtube videos. On our study tours we demonstrate real life examples.|