Title of Example

Example

The infrastructure planning sees the need for a new bridge crossing Göta älv river in Göteborg. The existing two bridges and the tunnel under Göta älv can’t handle more increase of the traffic, traffic jam occurs every morning and evening. One of the most exposed spots for air pollution is at the existing tunnel, Tingstadstunneln between Ringömotet and Gullbergsmotet. Something has to be done to reduce the air pollution in that area. The Environment Administration got the task to do the dispersal calculations and forecasting for year 2010 of NO₂ values for the different examples that were planned to be built. It is four places there it is possible to build a bridge, Lärje, Backadal, Nylöse and Marieholm. At one of the places it is also possible to build a tunnel under the river, Marieholm (Figure 1).

Figure 1 Map of the area for the planned bridges

The bases for the calculations are inputs from the road traffic. Traffic models and forecasting were made for each bridge and the surrounding roads including Tingstadstunneln. The forecast for Marieholm were the same for the bridge and tunnel. The traffic model showed that most reduction of the traffic at Tingstadstunneln gains if a bridge/tunnel is built at Marieholm. The further north the bridge is built the fewer cars will use the bridge.

The calculations were made by the software EnviMan Planner. Planner provides simulation of the air quality with dispersion models. The calculation shows that most benefit for the air quality is if the new connection is built at Marieholm. A tunnel is better than a bridge even if the tunnel makes higher concentrations close by the mouths. It does not make any difference if it is a tunnel or bridge for the connecting roads. If a new bridge is built at Nylöse, Backadal or Lärje the air quality in that area still would be below the directives for NO₂. None of the four examples make any significant difference for the NO₂ values at Tingstadstunneln. But a small improvement could discern in the air quality for all four examples (Figure 2-5).

The new crossing over Göta älv which was desired to be built was the one which had most improvement for the air quality, but I doubt it had anything with the Environment Administration and the dispersal models to do. It was the tunnel at Marieholm.

Figure 2 Figure 3

Dispersion calculation today Dispersion calculation bridge Lärje

Figure 4 Figure 5

Dispersion calculationbridge Marieholm NO2 Dispersion calculation tunnel Marieholm NO2

Last Updated

13th January 2005