To satisfy new legislation, the Norwegian Public Roads Administration implemented a national facade
insulation program encompassing 2,500 dwellings exposed to high levels of road traffic noise. Thereby, the road owner
brought the equivalent noise levels from road traffic in compliance with a new indoor limit of 42dB. Cost-effectiveness
analyses show that facade insulation was the least expensive noise-control alternative per dwelling. However, cost-benefit
analyses show that the benefits were less than 20 per cent of costs. One reason for the poor benefit-cost ratio is that only
the residents of the targeted dwellings benefit from at-receiver measures. Measures at the source and/or targeting the
propagation paths also provide noise benefits for residents living along the same streets as the most noise exposed and
inadequately insulated dwellings.
A mixed noise abatement policy employing low-noise asphalts in addition to facade insulation is therefore considered. For
750 dwellings where two or more of the dwellings were located along the same road stretch, low noise asphalts replaced
facade insulation as noise abatement method. Facade insulation was kept as noise abatement method for the remaining
1,750 dwellings. The mixed noise abatement policy costs more, but now provides total benefits that match the total costs.
Even higher benefit-cost ratios are obtained when reframing the economic analyses within the context of a national policy
to reduce noise annoyance, and when focussing solely on more densely populated areas where low- noise asphalts is a
viable alternative to facade insulation. Since environmental authorities are in the process of further lowering the indoor
noise limit, the road authorities should consider preparing an organisational and financial framework for implementing
low-noise surfaces based on cost-benefit calculations. Such a policy would have the added benefit of improving urban
soundscapes for a significant number of residents, workers, cyclists, pedestrians and children.