Crash cushions
A crash cushion is a passive or catching protective device that is usually made of steel or plastic, is used on roads with high traffic and is often designed as an impact base . Impact dampers are located in front of obstacles on or next to the road and are primarily used to reduce the severity of a vehicle impact for the vehicle occupants by converting kinetic energy into deformation energy. To make them easier to see, the impact absorbers are usually provided with a warning mark pointing to the side.
Concrete barriers are not called crash cushions because they do not deform in a collision. However, like boulders and other heavy objects, they can be used as impact protection. They soften the impact by shifting in the event of a collision.
species
Basically, a distinction is made between stationary crash cushions and mobile crash cushions:
- Fixed impact absorbers are placed in front of obstacles on the edge of the road. The obstacles include both larger installations (such as traffic sign bridges ) and entire structures (such as tunnel portals). In the event of an impact, the stationary impact absorber not only protects the vehicle occupants, but also prevents damage to the fixtures or structures.
- Mobile impact absorbers (also called TMA or Truck Mounted Attenuators ) are mounted on the rear of carrier vehicles that are used to protect workplaces of shorter duration . In the event of a collision, this not only reduces the stress on the occupants of both vehicles, but also protects the carrier vehicle and the staff employed in the workplace.
In some countries, crash cushions are used as a safety measure and at the same time to mark motorway exits, which consist of plastic tubs filled with sand or water.
Impact base
Impact bases are often provided as protective devices made of concrete on gantries or bridge piers . The end faces are typically semicircular in order to repel impacting vehicles. Often, an additional protective device in the form of a concrete protective wall or barrier is placed in front of the impact to reduce the impact .
Standards and regulations
- Germany
- DIN EN 1317-3 - Restraint systems on roads - Part 3: Impact absorbers - Performance classes, acceptance criteria for impact tests and test methods
- Guidelines for passive protection on roads through vehicle restraint systems
- Austria
- ÖNORM EN 1317-3 - Restraint systems on roads - Part 3: Performance classes, acceptance criteria for impact tests and test methods for impact absorbers
- RVS 05.02.31 - restraint systems; Requirements and placement
- Switzerland
- SN EN 1317-3 - Restraint systems on roads - Part 3: Performance classes, acceptance criteria for impact tests and test methods for impact absorbers
- SN 640 561 - Passive safety in the street space; Vehicle restraint systems
Web links
- Directional drawings for traffic sign gantries - Directional drawing 4 (PDF file; 1.52 MB)