clarifications of terms related to relevant topics.

The ASI index (Acceleration Severity Index) describes the severity of the vehicle impact, and is considered an important value for the occupant load. This value determines the severity of the load exerted on a vehicle occupant in a collision and is therefore decisive for their risk of injury. They must not exceed a certain level.

The containment level determines the criteria for the impact tests and thus determines the containment capacity of a vehicle restraint system based on the impact speed, impact angle and total mass of the vehicle.

Bridge parapets are an effective protection for road users and the structure. Solid and reliable vehicle restraint systems are even more essential on structures, as here the effects of an accident caused by a vehicle falling can be much more severe. This is also reflected in the national requirements for higher containment levels according to EN 1317.

Precast concrete safety barriers are vehicle restraint systems on roads made of precast concrete. They are intended to prevent uncontrolled departure from the carriageway, collision with vehicles and obstacles along the carriageway and falling from bridges and embankments. The precast concrete safety barriers manufactured by REBLOC consist of precast concrete elements that are connected with coupling systems to form a continuous chain of elements.

Depending on the type of construction and span of the bridge (temperature-related) changes in length (dilations) of between a few centimeters and almost one meter must be expected. In the area of carriageway transition structures, these occurring movements of the bridge structure must also be absorbed in the concrete guide wall system. Special dilatation elements are available for this purpose, which must also guarantee the function as a protective device. In particular, the tensile force transmission must be permanently secured in every position of the dilatation joint.

Road restraint systems must pass the tests according to EN 1317-1 to 1317-4. The standard specifies test procedures and acceptance criteria for the impact test. Breakthrough resistance is demonstrated at various levels and the safety of the occupants is checked. These standardized test procedures enable direct comparability of the systems and the suitable application based on their performance.

Vehicle intrusion is the maximum dynamic lateral position of a vehicle on impact. This refers to that part of the vehicle that protrudes beyond the protective structure and is assessed from high-speed photo or video recordings.

Vehicle restraint systems (VRS) are systems installed on the road to provide a level of containment for an errant vehicle. They are basically placed in those areas along roads where it is better for the occupants if the vehicle crashes against a vehicle restraint system. To ensure road safety, certain road sections require the installation of vehicle restraint systems. These must comply with the requirements of the European Standard EN 1317 "Road Restraint Systems", which regulates the criteria for the test procedures of road restraint systems in Europe.

Integrated Noise Barrier systems offer road safety and noise protection in one system. In addition to its function as a vehicle restraint system, it reduces noise pollution and can be used both temporarily during construction activities and permanently on the finished road.

ENV 1317-4 specifies the performance of transition structures that are considered to provide a connection between vehicle restraint systems of different types. It is required that the transition structures provide a uniform and safe transition from one vehicle restraint system to another.

EN 1317-2 specifies the requirements for the impact performance of vehicle restraint systems, containment classes, working width, vehicle intrusion and acceleration severity index.

Emergency openings enable emergency vehicles to reach the opposite directional lane, for example to reach accident scenes. The emergency opening elements are prefabricated in the factory and delivered with the corresponding integrated tool. This tool remains on site and enables fast and safe opening and closing of the continuous chain of elements without additional tools.

Permanent systems are used for permanent protection in the central reservation and at the edge of the carriageway. The vehicle restraint systems of containment level N1 to H4b are an integral part of the road equipment. REBLOC has a wide range of products and offers systems for numerous installation situations, such as on asphalt, concrete, compacted subsoil or on bridges. Different types of installation (free-standing, embedded, anchored) thus ensure a high level of safety.

Temporary systems provide safe traffic guidance for construction site areas. They separate the individual lanes and at the same time provide protection for construction site personnel and road users. In addition, the consequences of an accident caused by a vehicle leaving the roadway are reduced.

EN 1317-1 contains requirements for the measurement of impact performance and acceleration severity index of road restraint systems.

Transitions (the connection of two safety barriers of different designs and/or performances) ensure continuous protection are tested in accordance with European standard ENV 1317-4 by means of real crash tests.

The working width indicates the required space for a vehicle restraint system. The working width of different vehicle restraint systems is only comparable within the same containment level. The working width is composed of the system width and the lateral displacement of the vehicle restraint system in the event of a vehicle impact.