Abstract
In autumn 1989, after an experiment, Finland introduced a reduced speed limit system for wintertime. Speed limits were lowered by 20 km/h on accident prone main road sections. Since then the reduced speed limits have been expanded to cover almost the whole trunk road network. The reduced speed limits have turned out to be effective in decreasing fatal accidents especially on icy and snowy road surface. The accident reduction on main roads during the four winters after introduction of the reduced speed limits was 33 percent compared to the corresponding period before the change. On other roads and streets accident on slippery road surface increased 15 percent. (A)