Fewer persons troubled by traffic: environmental consequences of traffic re-routing in Oslo East during the last decade.

The re-routing of traffic in Oslo East has reduced residents' irritation from traffic, according to a comprehensive traffic and enviromental research programme conducted by the Institute of Transport Economics (TOI). The re-routing led to a dramatic reduction in traffic in most streets in Old Oslo between 1987 and 1996. The major changes resulted from the opening of the Valerengen Tunnel in 1989 and the closure of several streets. The Ekeberg Tunnel was less significant, and there were only minor changes from 1994 to 1996. The equivalent noise level fell from 64dBA to 60dBA, and 56% of the residents experienced over 3dBa noise reduction. The mean level of air pollution was also reduced considerably, especially between 1987 and 1994 and especially for particulates. A new traffic indicator was constructed, considering both traffic in the street where people live and effects within 50m of the highest traffic level. Residents interviewed considered traffic less of a problem than before, but still the major enviromental problem in their district. A clear relationship was found between degree of nuisance experiences, noise, and air pollution. Large differences were found between different local areas. Different traffic enviromental problems were found to be cumulative. Old Oslo still needs more improvements.