Transport and traffic planning stems from traffic safety. Speed control is an efficient way to improve traffic safety, as the risk of accidents increases when speeds rise. The gravity of accidents is largely dependent on the collision speed.
Speed limits in Helsinki have been lowered since the 1970’s. Today the limit in the inner city and city centre is either 30 or 40 kilometres per hour with the exception of the busiest main routes.
In the 1960’s, about 40 pedestrians per year were killed in traffic accidents. Today the average number is 4, although car traffic has nearly tripled since the 1960’s. One of the main factors contributing to the decline is reduced speeds.
Speeds are reduced in new housing areas by avoiding straight, excessively wide drive-through streets. Old areas often require other solutions, including street bumps and elevated pedestrian crossings.
- Street bumps are an efficient and cost-effective way to control speeds. Street bumps are built on streets where the speed limit is 40 kilometres per hour or less. Bumps are not suitable for areas with soft soil because of the vibration caused by traffic, and they are built on streets used by public transport only for special reasons. More bumps are requested than can be built with current budgets, and such busy streets are prioritized that are crossed by school children.
- Elevated pedestrian crossings are an efficient way to reduce speeds. But they are markedly more expensive than street bumps.
- Elevating a juncture improves the safety of all transport modes, but it is the most expensive of all elevation solutions.
- Roundabouts also reduce speeds efficiently. Dozens of roundabouts have been built in Helsinki since the 1990’s, and dozens more are being planned.
- Narrowed roadways and curves control drivers and reduce speeds especially when vehicles pass each other. Parking on streets can also be used to control speeds.
- An island in the middle of a pedestrian crossing facilitates the crossing of the street. At bus stops traffic can be controlled with long islands in the middle of the street that prevent vehicles from passing buses.
- Street markings and speed displays are efficient reminders and improve the effect of traffic signs. Speed displays are suitable for areas where street bumps cannot be built because of the vibration caused by traffic.
- Traffic lights improve safety at junctions efficiently and allow pedestrians and cyclists to cross streets safely. Traffic lights are installed on the basis of the number and speed of vehicles and the number of pedestrians. Usually traffic lights are installed only at busy street crossings where the speed limit exceeds 40 kilometres per hour. The location of schools and similar institutions may necessitate traffic lights. New traffic lights are installed sparingly, as safety at many junctions can be improved with roundabouts, which are better for the flow of traffic.
- Signal lights at pedestrian crossings warn drivers about pedestrians entering crossings. They may become a cost-efficient and flexible alternative for traffic lights in suburban areas.
- Mixed-use streets are for both pedestrians and vehicles, but pedestrians have the priority. The speed limit is 20 kilometres per hour. Such a street is not established with a traffic sign alone, but the street environment has to comply: the street can be narrowed, elevated and equipped with street furniture such as benches that control speeds. Streets on courtyards are usually included in detailed plans.
- Speed control is the responsibility of the police. In addition to traditional speed control, automatic speed control devices are applied. The City of Helsinki has acquired speed control devices for the police. The City has proposed a law that would allow municipalities to participate in automatic speed control to support the work of the police.
- Drive-through bans are very seldom used to improve traffic safety. Bans are very inefficient because the police have little means to control compliance with them. Drive-through traffic is directed away from residential streets by other means, including reduced speeds. The best way to reduce drive-through is to make some other route more attractive.
Initiatives for street bumps and other means to improve traffic safety should be sent to the City of Helsinki Register Office by mail or email. An idea can also be discussed with the area’s traffic planner.
The City Planning Committee approved the principles to reduce speeds in November 2009. Read proposal (In Finnish) >>