Dutch roads go underground
More and more roads and motorways in the Netherlands are going underground. Motorists are continually running up against roadworks for the construction of new tunnels. The main reason for putting roads underground is the environment.
There are already around 25 large tunnels in the Netherlands. Most of them go under waterways. But in recent years there has been a rapid increase in the number of land tunnels, which just hide the roads.
Engineer Stephan Lezwijn works for the Underground Construction Centre (COB) and he explains why land tunnels have suddenly become so popular.
"The economy is still growing and so is welfare. That automatically leads to more mobility and therefore more infrastructure. Where people used to put up with a road along the edge of their gardens, it is certainly not possible nowadays. So underground solutions are on the increase. Even in wooded or nature areas, people are less prepared to accept the nuisance of having a road."
The new Hubertus Tunnel in The Hague is a good example. It is 1600 metres long. On top of it is a beautiful park which has been left undisturbed by digging the tunnel. There are also office blocks and houses on the route of the invisible tunnel, and they are not bothered by the busy traffic.
You could see land tunnels as an expensive environmental measure. But that is not entirely true. Building new roads means car use increases. That is a general rule, and it wipes out any environmental benefits of covering the traffic. At the tunnel openings there is actually more pollution. According to Mr Lezwijn this is a point the road builders should take into account:
“More measures need to be taken. Chimneys and filters for instance. But more than anything the location of the tunnel mouth and the proximity of housing needs to taken into account on the drawing board."
Most land tunnels are actually long concrete shoe boxes covered by a layer of earth. Quite a few are due to open soon, or are planned. The world’s longest at 3.5 kilometres is planned for a motorway from the Dutch new town Almere to Amsterdam’s Schiphol Airport.
This is an alternative for a proposed tunnel under the Naarden Lake nature reserve which was scrapped after prolonged protests. But the motorway will eventually have eight lanes which makes you wonder whether it is better for the environment in the end. But at least the lake will not be affected.
Land tunnels are expensive, very expensive. It depends from case to case how much more expensive it is to build a tunnel rather than a road. However, according to Mr Lezwijn, it is always many times more expensive. Because it is a hot item for both politics and public safety, the measures are strict:
"Most of the measures are about making it possible for people to escape in case of an emergency. We’re talking about alarm installations and escape doors. The average number of escape doors for roads in the Netherlands is 10 per kilometre. Behind the door is a space which is fire resistant and safe enough for long enough until the emergency services arrive. Most tunnels have a special escape route which allows people to flee to the surface."
There is just one thing that no safety measures can take away and that is that sense of unease as you drive into a tunnel. But that is something we will just have to get used to: “Motorways are increasingly going underground, they just have to.”
Thijs Westerbeek van Eerten