Speed limits on most streets in residential areas of the capital are being lowered to 30km/h.
Based on a decision taken last year, lower limits are being posted starting this month, with the full roll-out expected to be completed by the autumn.
The biggest change is a reduction of the speed limit in nearly all residential areas of the city. At present, about half of city streets in residential areas are posted at 40km/h. Most will be reduced to 30km/h.
Speed limits in the city centre will also come down to 30km/h, except on main thoroughfares and on routes to and from the city's harbours. These will be posted at 40km/h.
The current 50km/h speed limit on Mannerheimintie will be reduced to 40km/h on the section between Finlandia Hall and Kuusitie.
Little impact on drive times
Lower speed limits are expected to be reflected in fewer traffic injuries in the city.
Reetta Putkonen, who heads Helsinki's transport planning division, states in a press release that with lower speeds the probability of being involved in an accident declines, and the effects of any accident are less severe. When the speed of impact on a pedestrian is lowered from 40km/h to 30km/h, the risk of fatality is cut in half, she points out.
According to Putkonen, the new speed limits will have little effect on drive times since the limits will remain in force on the region's ring roads and there will be few changes on commuter feeder routes in and out of the city.
Transport officials say that in central Helsinki average daytime traffic speeds on many streets are actually lower than the new limits being posted.