Comparison of Road Traffic Noise Calculation Models

The results of a round robin test on road-traffic noise calculation schemes are presented and analyzed for differences. On the basis of the information supplied, corrections were applied to make results more comparable.

Every day situations, as simple as possible were presented, such as straight, asphalted roads with no reflections, ramps, curves or blocks.

The spread in results is large, from 6 to 10 dB, with larger differences for the motorways and for the night situation.

On closer examination of the calculation models the source models were seen to cause the largest differences.

The conclusion is therefore that before comparing noise levels and standards between countries, one should be aware that large unexplainable differences result when the same situations are calculated with different methods. The differences vary between 6 and 10 dB(A), even after correction. This means that the differences when comparing official outcomes (according to the national standards) may be even larger.

The need for combined effort to establish a common calculation method is obvious. From the data it seems impossible to prepare a translation between methods since the differences lack any trend.