Transitions from one type of infra to the other

Source: BicycleDutch

  “Occasionally it will be necessary to provide a transition from on-carriageway cycle lanes to off-carriageway cycle tracks and vice versa. This transition should be clear, smooth, safe and comfortable for cyclists. Minimum speed change and vertical and/or horizontal deviation for cyclists should be the objective.”

Not my words, but I couldn’t have said it better myself. This is from the draft of the revised London Cycling Design Standards by Transport for London (TfL) that was under consultation in the summer of 2014. (Par. 3.2.28)

Not quite designed according to the draft design standards. This cycle track starts and ends on the side-walk right at a pedestrian crossing. (London)

Not quite designed according to the draft design standards. This cycle track starts and ends on the side-walk right at a pedestrian crossing. (London)

And there is more wisdom in that draft:

“It is particularly important not to have a vertical step change in level along a line running along the general direction of travel. This can happen if cyclists are directed to cross at a shallow angle over a dropped kerb that has not been laid properly. Such situations can de-stabilise cyclists’ steering.” (Par. 3.2.29)

But what I found in London so far, does unfortunately not meet these descriptions. My photo below (a picture I took for a blog post in 2012) shows a dropped kerb at the Vauxhall gyratory, that is indeed not properly laid. The kerb has not been dropped in the right place (the drop should have aligned with the white line and the kerb in the direction of travel) and it has also been dropped too far, creating a puddle after the rain.

A transition in London. A dropped kerb in the wrong place, not wide enough and too deep, so a puddle forms. The situation hasn’t changed, according to Google StreetView.

A transition in London. A dropped kerb in the wrong place, not wide enough and too deep, so a puddle forms. The situation hasn’t changed, according to Google StreetView.

And London is not alone. Other countries have trouble creating good transitions as well. When I was in Australia last year I saw some very promising cycling infrastructure. But it would stop right before junctions, forcing people cycling up the side-walk and across pedestrian crossings.

A cycle track in Brisbane that ends and starts on the sidewalk. (This location in Google StreetView)

A cycle track in Brisbane that ends and starts on the sidewalk. (This location in Google StreetView)

I have argued before that cycling infrastructure is most important at junctions. Because that is where most accidents and crashes take place. Rather than to stopright before junctions, cycling infrastructure should start right before you reach those. That means that there will be some transitions right before and right after junctions.

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A rare transition in a straight stretch of street in ʼs-Hertogenbosch.

Transitions in the middle of straight stretches of streets are unusual in The Netherlands, because of the Sustainable Safety policy. Under that policy all roads and streets are categorised. Specific categories of streets and roads require specific cycling infrastructure, but that goes for the entire road or street. A change in the type of infrastructure in the middle of such a street or road is therefore very unusual. There either is separated cycling infrastructure (on through roads) or you will not find it (on residential streets in a 30km/h zone). That is why you usually only go from one type of infrastructure to the other when you turn a corner, to get from one type of street into another.

A transition from an on street cycle lane to a separated cycle track right before you reach a roundabout.

A transition from an on street cycle lane to a separated cycle track right before you reach a roundabout.

If you exit a 30km/h zone from a small side street and you turn into a main street, the transition will take place right at the corner. At the larger junctions the transition often takes place before you reach the junction. That means first of all, that there will be separated cycling infrastructure at the entire junction. Which means that the design principles of junctions can then be exactly the same, whether all streets leading to the junction have separated cycling infrastructure or not. In second place that makes junctions more clear. When junctions are designed in a similar way, they are understood more easily and quicker, and that makes traffic situations safer. Finally it makes cycling past red lights possible.

Both these junctions are designed in a similar way, with protected cycling infrastructure on the junction itself. Even though the junction on the left has two streets leading to it without cycling infrastructure, (North and South) and the size of the junctions is very different.

Both these junctions are designed in a similar way, with protected cycling infrastructure on the junction itself. Even though the junction on the left has two streets leading to it without cycling infrastructure, (North and South) and the size of the junctions is very different.

This roundabout has cycle tracks with priority for cycling. The preferred type of roundabout in the built-up area in The Netherlands. Even though the street coming from the west has no separated cycle tracks. Note also how the junction with the smaller side street on the right (without cycling infrastructure) is designed.

This roundabout has cycle tracks with priority for cycling. The preferred type of roundabout in the built-up area in The Netherlands. Even though the street coming from the west has no separated cycle tracks. Note also how the junction with the smaller side street on the right (without cycling infrastructure) is designed.

The approach from the street from the west of the above picture looks like this on the surface. Note that the transition looks much shorter than it really is. It is over 10 metres (30 Ft) long.

The approach from the street from the west of the above picture looks like this on the surface. Note that the transition looks much shorter than it really is. It is over 10 metres (30 Ft) long.

The Dutch design principles for transitions are like those of TfL I mentioned before. You should be able to make the transition in a safe way and at a reasonable speed. So they must be clear, with wide turns, under shallow angles, with clear sight lines for all road users and the surface must be smooth, especially when the type of surface changes as well.

From a separated cycle track to a street without any separated cycling infrastructure into a 30km/h zone. The transition is very long and smooth. It resembles an entrance to a motorway.

From a separated cycle track to a street without any separated cycling infrastructure into a 30km/h zone. The transition is very long and smooth. It resembles an entrance to a motorway.

The video and the pictures in this post show you examples of transitions between different types of cycling infrastructure in The Netherlands. What is most important is that transitions connect different types of infrastructure in such a way that you can cycle on, at speed and in a safe way. Continuity in your ride, even while you encounter very different types of infrastructure is important to make your ride convenient and safe. With smooth transitions that is very possible.

Video: transitions in cycling infrastructure in The Netherlands