Focus on guardrails: legislation and dimensions of road barriers to limit the consequences of vehicles leaving the road
THE bodyguard is a passive safety and restraint device that is used to contain vehicles on a roadway following a skid or a collision with other vehicles. It is by far the road safety barrier the most used in the world with Jersey barriers. It goes without saying that installing a bodyguard is subject to strict legislation particularly with regard to the size Hey materials.
- Purpose of the guardrail
- Reference legislation
- Where to install the barriers
- Technical characteristics of the guardrail
- Railing materials
- Motorcyclist guardrail
Update March 24, 2023 with the implementation of the latest regulations in terms of road safety barriers or guardrails.
PURPOSE OF THE GUARDRAIL
THE bodyguard o safety barriers are installed essentially with the aim of creating, for road users and any outside persons present, acceptable security conditions in relation to the configuration of the road infrastructure, guaranteeing, within certain limits, the vehicle containment which may tend to leave the roadway.
The impact with the guardrail must therefore cause minor damage of any uncontrolled exit from the vehicle.
Therefore, road safety barriers must be adapted to the absorb part of the energy with which the vehicle is equippedwhile limiting the impact effects on passengers.
GUARDRAILS: REFERENCE REGULATIONS
Over the years, Italy first regulated the design, validation and installation of road safety barriers with Ministerial Decree n. 223 of February 18, 1992 and then with Ministerial Decree no. 2367 of June 21, 2004, supplemented several times by subsequent circulars. However, these decrees are largely superseded by the publication of EU Regulation 305/2011, which established harmonized conditions in all member countries for the marketing of construction products. Indeed, since the entry into force of the European regulation, entry into the Community market for guardrails presupposes the CE markings in accordance with the harmonized standard UNI EN 1317 which establishes procedures for testing and certifying barriers.
GUARDRAILS: WHERE BARRIERS SHOULD BE INSTALLED
THE areas to protect with road safety barriers and other restraint devices must cover at least:
- THE margins of all outdoor street art such as bridges, viaducts, footbridges, overpasses and retaining walls of the roadway, whatever their longitudinal extension and their height in relation to ground level;
- THE traffic splitter if applicable;
- THE lateral road edge in sections of embankment when the difference in height between the crest of the embankment and the level of the ground is greater than or equal to 1 meter; protection is required for all embankments with a slope greater than or equal to 2/3, in other cases it depends on the combination of slope and height of the embankment, taking into account the potential danger situations downstream of the embankment (presence of buildings , roads, railways, hazardous materials depots, etc.);
- THE fixed obstacles (front or side) that may pose a hazard to road users in the event of a collision, such as bridge piers, rocky outcrops, impassable drainage works, trees, light poles, non-yielding sign supports and courtyards of water, as well as manufactured goods such as public or private buildings, schools, hospitals which, in the event of a spill or collision with vehicles, could be damaged, thus causing danger also to non-road users. In particular, it is necessary to protect the aforementioned obstacles and artefacts if they are located at a distance from the outer edge of the roadway that is less than an appropriate safety distance (which varies according to various factors).
Read more: Railings in poor condition: who pays for the damage in the event of an accident?
GUARDRAILS: TECHNICAL CHARACTERISTICS
Railings installed in Italy and the rest of the European Union must comply with the parameters defined by the harmonized standard UNI EN 1317 on road safety devices which, as mentioned, establishes procedures for the testing and certification of barriers. The standard is itself divided into 8 parts, but for certify a road barrier we mainly refer to 3 specific parts:
- UNI EN 1317-1 (Terminology and general criteria for test methods)
This European Standard provides provisions for measuring the performance of road restraint system products subjected to impacts and levels of impact severity. It includes test site data, road restraint system definitions, vehicle specifications (including loading requirements) for vehicles used in crash tests, vehicle instrumentation, calculation procedures and methods of recording crash test data, including crash severity levels and vehicle cabin deformation index. (VCDI).
- UNI EN 1317-2 (Performance classes, impact test acceptance criteria and test methods for safety barriers)
This standard specifies impact performance requirements for road restraint systems, including vehicle guardrails, containment classes, operating width, vehicle intrusion and impact severity levels.
- UNI EN 1317-5 (Product requirements and conformity assessment for vehicle restraint systems)
The standard specifies i requirements for conformity assessment of safety barriers, impact attenuators, bollards, transition elements, vehicle/pedestrian guardrails. Does not apply to temporary barriers. Among the requirements, the sustainability: all vehicle restraint systems, in fact, must be durable for an economically reasonable, duly demonstrated life. For this purpose, it is necessary to declare the materials and the protective coatings used in the manufacture of the safety barrier, specifying their technical characteristics and their impact on the durability (for example, the protective treatment of the steel or the composition and thickness of the concrete).
Then there is the fundamental part of the conformity assessment. Compliance of the road safety barrier with the requirements of the standard shall be demonstrated by initial ITT laboratory testing and crash testing for the barriers, as well as factory production control by the manufacturer, including the product evaluation. In summary, the evidence for crash tests are necessary to verify the basic requirements of a guardrail: 1) the containment capacity of the design vehicle; 2) the correct return of the vehicle to the roadway following the collision; 3) minimizing the risk of injury to occupants of light vehicles by limiting deceleration.
Read more: Guardrail crash tests: When and how quickly do they become deadly?
Guardrails can usually be in steelIn concrete or in drink (with steel core), where environmental requirements require it. THE materials with which the safety barriers are built must meet the essential requirements of mechanical resistance and durability, as well as environmental compatibility characteristics and aesthetic qualities, where applicable. In their most traditional configuration, metal barriers consist of the following structural elements:
- uprights: fixings to the floor or bolted to the support;
- band(s): generally made up of one or more plates in the form of a double or triple wave;
- longitudinal currents: elements arranged parallel to the strip, lower (wheel guard) or upper (in correspondence with the engineering structures);
- spacers: if present, placed between the belts and the uprights and having the function of dissipating the energy of light shocks and guaranteeing the lifting effect of the belt on impact in order to avoid crossing the barrier ;
- bracing diagonals, if any;
- connection and stress bolts;
- stud anchor or drive brackets.
THE bodyguard are protection systems specially designed for i four wheel vehicles. Conversely, they have often proved to be completely useless, even extremely dangerous, for bikers. Indeed, in the majority of accidents, fatal injuries to the spine do not occur during a motorcycle accident, but when after the impact the motorcyclist is ejected from the vehicle by hitting the guardrail, curbs or other roadside barriers. Thus, for some years, with the ministerial decree of April 1, 2019, the so-called guardrail “biker saver” (DSM) of yellow color which must be installed in the lower part of the traditional barriers, at street level, to avoid direct impacts against the uprights or against the protection strips of the railings. However, the obligation does not apply to all roads, moreover (strange but true) the DSMs currently installed do not comply with the reference decree.
Source : Sicur Auto