Title of Example

Example

Utrecht was a compact city: expansions around the old centre were limited and surrounded by highways and a canal. With the new suburb 'Leidsche Rijn' being reclaimed it is divided in two parts by a highway and the canal. New bridges over the canal and ‘covering’ the highway should remove the barriers and unify the suburb.

To protect air quality and to prevent noise it was proposed to cover 1,5 km of the road. But the ministry of transport, the most important financier, gave priority to internal safety. Because there was no physical need, like a canal, for covering the highway, the ministry didn't want to introduce a risk of accident with a lot of casualties. Even with safety measures that would have made it the safest tunnel in Europe, it was not acceptable.

The parallel roads for through traffic could be covered if the transport of LPG was via another route. And only parts of the main highway of 350 metre at the most could be covered. A screen along the open parts should reduce the area not suitable for living regarding high air pollution and traffic noise.

A few years ago the municipality of Utrecht accepted this solution, because discussions about safety were influenced by some recent accidents in European tunnels.

The minimum distance between new houses and the middle of the motorway is calculated with the help of windtunnel measurements. It is possible this distance has to become larger because of new, more pessimistic air quality scenarios. There is also a difficulty with the use of the area between the houses and the highway. It will not be a residential area. But what kind of use is acceptable? The structure should force the right use. The designers hope to get more starting points from the air quality policy.

Last Updated

13th January 2005