All over the Netherlands cities are working to get rid of missing links in their cycle grids. That is often done by building viaducts or underpasses, overpasses or bridges. But a missing link can also be bridged by a cycle street through a residential area. This week I will show you how ʼs-Hertogenbosch (aka Den Bosch) completed a cycleway alongside a rural road that was interrupted for exactly 175 metres. (574Ft)
At the edge of ʼs-Hertogenbosch proper there is an area with heavier industry. To stop larger trucks driving from that area to nearby Engelen (a former village that now also belongs to the municipality of ʼs-Hertogenbosch) to take a short-cut, the road to that village was closed for trucks. A turning point for trucks was built in the street and from that point traffic was much thinner. Probably the reason why the separated bi-directional cycleway stopped right there. People cycling had to share the road when they wanted to cycle further on. The shared road then went under the A59 motorway, directly next to the river Dieze. Right after that narrow underpass another bi-directional cycleway started. It runs partly parallel to the motorway and it gives people the opportunity to cross the river, or to go in two other directions. I showed the underpass in an earlier video, in which I filmed all possible points where you can cross the motorways around ʼs-Hertogenbosch. This was crossing number 19, at the time one of the few crossings without cycling infrastructure.
That stretch of road on which people had to share the same space, between the turning point and that other cycleway, was exactly 175 metres long, or perhaps I should I say short. The connecting cycleways on either end are both bi-directional. Because of that, and because you have to ride on the right hand side on a shared road, people cycling north had to cross that shared road twice. That is unwanted, especially since this street is part of the well-used recreational cycle network. And so the city decided to connect both cycleways with a new stretch of cycleway, alongside of the road, when they had a good opportunity; when the road was due for substantial maintenance.
That was easier said than done. There were some problems to overcome. The road also functions as a dike. It is part of a regional defence system against high water. So you couldn’t simply change that road. That is also why there is a pumping station to regulate water levels in the area. Unrelated, there also is a power substation. And, the biggest problem; the narrow underpass right next to the river was a true bottleneck. The only way to create enough space under that bridge, was to remove part of the base of the bridge. But you can’t just take away a big lump of the base of a bridge of course. So a very elaborate investigation into the soil mechanics was done. To make clear if the forces of the motorway on top of that bridge, that were led away through the base, would not be dangerous if part of that base was removed and replaced by a concrete wall. The investigations resulted in a 96 page report. It is full of tables with geotechnical calculations of forces on the soil, but also on anchors and struts that would be placed. Part of the investigation is in English. It is very complicated, but at least the conclusion is clear: it could be done, without risking the stability of the motorway bridge and the dike.
That meant sufficient space could be created under that bridge. The roadway was narrowed and, following the latest design specifications, the centre line was removed. The bi-directional roadway now has a width of 4.8 metres, or 5 metres if you include the gutters. The new bi-directional cycleway is 3.5 metres wide and slightly narrower under the viaduct. But with 3.2 metres there, it is still within acceptable design specifications.
For rainwater to run off (also water that comes all the way down from the motorway) both cycleway and roadway slope 2% in the direction of each other. Rain water is collected in the gutter between the two.
Maybe the most interesting fact in the profile is the clear specification of all the layers of the surface of the cycleway. On the original soil there first is a base, formed by a sand bed with a height of 30 centimetres. On this base we find the foundation: 20 centimetres of granulated concrete. Then we get to three layers of asphalt. First there is a 65 mm base layer (type AC 22 O1-B). On top of this base layer, the bind layer is formed by 44 mm of asphalt (type AC 16 bind T2). Both these layers are normal black asphalt. The top layer is in red asphalt and 25 mm thick (type AC 8 surf PMB). So the total height of the cycleway surface, including the foundation, is an impressive 63 centimetres (2.07Ft). Strong enough for maintenance vehicles (like snow removal machines) to use that cycleway without damaging it. The cycleway can also be crossed by larger vehicles, that need to reach the pumping station or the power substation. The surface of the narrowed roadway was also completely renewed. The works were carried out in stages. The roadway was narrowed and got new asphalt in September 2013. The reconstruction of the base of the bridge and the construction of the cycleway took place in April/May 2014.
In the new situation the cycleway is completely uninterrupted and people cycling north (away from the city) do no longer have to cross the road twice! Both crossing moments were completely eliminated. For people cycling the other way, one junction with a stop sign (rare in the Netherlands) was also removed. You can now simply cycle on without any interference of other traffic.
The new cycleway is only 175 metres long, but it makes cycling safer and more convenient. One more gap in the cycle grid is now completely gone.
My video with a before and after side by side.