Esri Shape file

From the dataset abstract

The data includes traffic noise zones in the Helsinki metropolitan area (Helsinki, Espoo, Vantaa and Kauniainen). The dataset contains a breakdown of road and rail traffic noise zones, as well as day and night times.

The coordinate system of the dataset is ETRS-TM35FIN.

The noise calculations were carried out at a power workstation specifically purchased for the noise calculations. The calculations took place between November 2011 and January 2012. The calculation times for all situations ranged from 8 to 12 days. The calculation time depended on the number of details in the city’s noise model and the city’s surface area.

Source: Pääkaupunkiseudun liikennemeluvyöhykkeet