How does the Berlin cushion work?

Berlin cushions, rectangular concrete devices, are used to slow down cars without disturbing other road users. They are narrow to allow passage for cyclists and buses without touching them, but wide enough for cars to have to cross over at least one side. These cushions are used to enforce 30 zones where speed is limited. Originally tested in Berlin, these devices have gained popularity in the city, which has reduced the speed of nearly 70% of its roads to 30 km/h.

Origin, operation, and performance

Evolving history

Germany introduced speed bumps in the 1970s, inspired by results from the Netherlands. Delft humps were successfully tested in Krefeld in 1988. In France, Berlin cushions are often used, smaller and easier to cross for trucks and cyclists.
German speed bumps aimed to slow down traffic in residential areas. The Krefeld cushions emerged from a successful test project conducted in Krefeld in 1988. These devices are designed to improve road safety and reduce vehicle speed.
The Berlin cushions, adapted from the German model tested in Berlin, offer an effective alternative to traditional speed bumps. Their size allows trucks and cyclists to pass without difficulty while maintaining an effective speed limit.
In summary:

  • Germany – Introduction of speed bumps in the 1970s
  • Speed bumps – Successfully tested in Krefeld in 1988
  • Berlin cushions – French adaptation offering a more flexible solution
  • Road safety – Main objective behind the use of these devices.


Regular speed bumps can slow down all types of vehicles.
Berlin cushions are more suitable for European vehicles with closer axles. Emergency vehicles can distinguish them by their width between wheels.

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Berlin cushion: effectiveness

Speed is a major factor in urban accidents. To address this, authorities have implemented 30 zones, which significantly reduce the number of accidents. Different devices such as speed bumps and Berlin cushions are used to slow down traffic and ensure the safety of residents.

Practical application

Authorization in France and implementation

Decree 94-447 of May 27, 1994 establishes standards for “speed bumps” and “trapezoidal” speed reducers. These standards do not apply to cushions and raised plates. Recommendations for the use of Berlin cushions are provided by CEREMA, an organization under the supervision of the ministries of Ecological Transition and Territorial Cohesion.

Rubber cushions must meet a specific adhesion measurement according to standard NF EN 13036-4. Non-compliance with standards can have legal consequences, as confirmed by the Administrative Court of Appeal of Lyon in a recent ruling.

Berlin cushions made of vulcanized rubber or prefabricated concrete have a trapezoidal shape that must comply with the restrictions and constraints of decree 94-447 and standard NF 98-300. Their use must therefore be done with caution on public roads to avoid any legal problems.

In France, the cost of a Berlin cushion is generally lower than that of a traditional speed bump, which can represent significant savings for local authorities wishing to equip their roads with these devices.

United Kingdom: changes

Berlin cushions are devices installed on the road to reduce vehicle speed. They can be used in areas where the speed is limited to 30 mph. Different materials, such as concrete, paving, rubber, and asphalt, can be used for their manufacture. The cost varies depending on the chosen material.

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These cushions have been tested to assess their impact on different types of vehicles. The results show that they do not cause excessive discomfort for long buses and fire service vehicles, but can be more troublesome for shorter buses and ambulances with double rear wheels.

It is recommended that the height of the cushions does not exceed 80 mm at the absolute end to prevent vehicles from touching the ground. The suggested optimal dimensions are a length of 3.5 meters, a width of 1.6 meters, and a height of 65 mm with an adequate slope.

Experiments have also shown that the speed practiced varies depending on the width of the Berlin cushion: about 30 km/h for a narrow cushion of 1.6 meters and about 23 km/h for a wider cushion up to 1.9 meters.

In conclusion, the use of these devices can help improve road safety by effectively controlling vehicle speed in specific areas while minimizing the discomfort experienced by users.

Challenges to overcome

Traffic calming devices, such as vulcanized rubber Berlin cushions, are affordable devices but must comply with regulations. It is essential to monitor and regularly maintain these equipments to ensure their effectiveness and safety. New generations of cushions have improved consistency with the roadway and reduced risks for users.

However, some motorcyclists criticize these devices, especially if they are not approved or incorrectly installed. The government insists on the road manager’s responsibility for any non-compliance or issues related to these speed bumps. Disused concrete cushions can also pose problems due to a too high friction coefficient.

The lifespan of the devices varies depending on traffic and the quality of installation. It is crucial to be vigilant about the rapid wear of Berlin cushions as well as the strength of the fixings to avoid any potential danger on the road.

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Infrastructure restrictions

Berlin cushions must be marked, signaled, and lit outside of 30 zones.

Inappropriate behaviors

Some drivers behave poorly in the presence of Berlin cushions. They may drive in the middle of the road or encroach on the space of cyclists, which can be dangerous.

Modification options

Smart speed bump

The smart speed bump, also known as the Tope Inteligente in Mexico and the Actibump system in Sweden, is an innovative alternative to slow down vehicles without causing discomfort. Thanks to an integrated intelligent radar, it automatically retracts when a vehicle respects the permitted speed. This energy-efficient system can support heavy loads while ensuring road safety.

Difference between chicane and lock

Urban chicanes are effective in slowing down traffic without causing discomfort. Well-designed chicanes can adjust the speed of vehicles according to their size. For example, a chicane may allow a light car to pass at 50 km/h but limit a heavy truck to 30 km/h.

On the other hand, locks combine the advantages of chicanes and Berlin cushions without disrupting cyclists on their route.

Speed bumps, cushions, or plates are subject to strict standards to ensure their effectiveness. Some devices, such as “Berlin cushions,” have been subject to legal controversies due to their reduced cost. Innovations like the “smart speed bump” offer more advanced solutions in terms of road safety. Research and regulations on traffic calming devices aim to improve traffic flow and protect road users.