What is a road restraint system (RRS)?
A Road Restraint System is a safety product, which aims at reducing the consequences of accidents of an errant vehicle.
Road restraint systems can be divided in:
Road safety barriers – the road barriers are placed along the roadside or on the central reserve; their role is to prevent errant vehicles from crashing on roadside obstacles, and to retain them safely.
Crash cushions – the crash cushions are collapsible structures that prevent vehicles (usually cars) from impacting specific hazardous sections (eg: the beginning of the central reserve). They safely stop the vehicle, avoiding worse consequences.
Terminals for road safety barriers – Terminals are the ending part of a safety barrier; their role is to avoid those parts from becoming dangerous points for vehicles.
Motorcycles protections systems – MPS represent an integrated system or an upgrade which, if applied on a road safety barrier, can reduce the consequence of impact for a motorcyclist after falling.
Transition between 2 safety barriers – Transitions are products which connect two safety barriers, guaranteeing structural continuity and a correct passage from the performance of the first barrier to the following one without creating black spots in those critical points
Each of those products have to comply with several safety requirements, which takes into account the safety of the occupant involved in the crash as well the safety of incoming traffic, both on the same lane and on the opposite one, depending on their location (lateral/central).
To assess those requirements, crash tests must be performed on each of those products (2 to 6, depending on the type of product); they aim at recreating ideal situations representative of the worst possible real-case that may happen in real-life, considering the “state-of-the-art” of crash-testing technology, the repeatability of the tests and, of course, the need to assess reliable safety features.
What does a road restraint system do?
A road restraint system is generally a collapsible or sliding structure that, through its deformation or displacement, absorbs part or all of the energy of a vehicle that hits it, and redirects and/or stops it safely for the driver and for the other road users.
The EN 1317 is the standard that establishes common European criteria to assess the performance of Road Restraint Systems.
It states which tests shall be undertaken to comply with the norm, how they must be performed and which criteria shall be assessed, in order to identify the most important features of the products and the performance it has in defined situations.
How are road restraint systems used?
Road Restraint Systems have different goals, according to the specific product:
Road safety barriers: Their goal is to prevent an errant vehicle from leaving the road way. This is extremely important when a driver has lost control of his vehcile and is about to impact an unprotected road side obstacle. Even more crucial is the role of road barriers used in the central reserve to prevent a vehicle from crossing it and, so, to avoid the possibility of a frontal impact on motorways or double carriage roads.
Crash cushions: crash cushions are collapsible devices, and their role is to avoid frontal crashes on ‘sensitive’ spots such as motorways exit, in order to reduce the consequences of an accident.
Terminals: terminals are the ending parts of a barrier; their role is to ensure that the ending point of a barrier does not become a hazard for road users that may impact them frontally.
Transition between 2 safety barriers: Transitions are products which connect two safety barriers, guaranteeing structural continuity and a correct passage from the performance of the first barrier to the ones of the second without creating black spots in those critical points.
Motorcycles restraint systems: those products aim at reducing the consequences of an accident when a motorcyclist slides out of the road.
Each country establishes in its national regulation which kind of protection should be used, according to the different situations that may be present on the road network (e.g. which barrier to use on bridges? Which minimum containment level in each situation?), and establishes the different installation and maintenance procedures together with any additional needs not covered by the norm.