Whether it is a natural feature or a man-made barrier, we sometimes need to build bridges to get our cycle routes across them.
Now, I am not talking about crossing a road at surface level here, I am interested in rivers, large roads and rail where we need to be using a bridge of some kind and for those moving under their own steam, the key issue is one of energy and minimising effort expended in getting across the obstacle.
The best solution of course is to keep the crossing level so that no energy is lost. To do this, we either have to raise or lower the obstruction. If not, we’ll have to use ramps to get over or under the obstruction or possibly meet halfway.
The photo below was taken in Malmö and shows the road and cycle track having to dip under a railway. The thing about railways is they are most efficient when built flat and unless you can rebuild a long section (which does happen sometimes), then you have to work with what you have.
Going under something is quite good for cycling because you don’t need too much headroom – about 2.5m is enough. The example above shows the contrast between cycling and general traffic with the latter needing about twice the clearance. To ensure we don’t lose too much energy, slopes are very gentle. We can even do this in the UK as shown in the photo below taken in Stevenage.
Even if we have to leave the obstacle alone, dipping under it with long ramps isn’t terrible, even when they are perhaps a little steep such as this example from Harderwijk;
Of course, there are much nicer Dutch examples such as this one on the outskirts of Amsterdam where the motorway is on an embankment;
There are obviously economic considerations in terms of raising or lowering infrastructure, but if we aim to keep people cycling at grade, then we’ll provide the best outcome. If we are building a new motorway (or rebuilding a junction) we may be able to lift the levels a bit which means we don’t have to drop the cycle crossing as much.
The Ranty Highwayman: Bridging The Gap
Whether it is a natural feature or a man-made barrier, we sometimes need to build bridges to get our cycle routes across them. Now, I am not talking about crossing a road at surface level here, I am interested in rivers, large roads and rail where we need to be using a bridge of some… [Read More]
