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Wire rope safety barrier is a flexible system which deviates along with the impacting vehicle slowly absorbing the energy of the impact and redirecting the vehicle back to the road. The high tensile wire ropes are released from the posts and cradle the impacting vehicle to avoid cross over or tipping over of the vehicle. Owing to its flexible nature and high tenacity, this barrier system keeps the impact severity (force felt by passengers and vehicle) to a minimum for both the vehicle and passengers.
Various standards have been developed, and these are described below.
The Indian Road Congress published its first ever guidelines for traffic safety barriers for use on Indian roads in January 2015 (IRC:119), covering concrete, metal beam and wire rope crash barrier systems. IRC:119 has taken into account importance of using crash tested barriers systems and have made it mandatory for all systems to be tested and approved as per EN-1317 or NCHRP:350 norms. The IRC has also included Wire Rope Safety Barriers in its manual for Specifications of 2-Lane, 4-Lane and 6-Lane Highways, as well as the Expressways manual. The IRC has recommended that Wire Rope Safety Barriers shall be supplied by a reputed supplier having approvals for a system adhering to EN-1317-2 norms for test levels N2 / H1 / H2.
Standards have been developed within the European standardisation body, CEN (Commite Europeen de Normalisation), for how impact tests are to be performed on road safety barriers. These road barrier impact tests are described in CEN 1317, Road Restraint Systems. The CEN standard imposes functional demands on the road road safety point of view. According to the CEN standards, the road barriers are to be impact-tested at different containment levels. The elongation of the road barrier is also measured, and this determines its working width. The road environment in which the barrier is to be constructed determines the appropriate containment level as well as the permissible working width. Furthermore, the CEN standard requires that the risk of injury in a collision with the barrier is minimised (injury risk class). This standard is used in the European countries and is common in countries near to Europe as well as in Australia and New Zealand, among others.
NCHRP stands for the National Cooperative Highway Research Program, a program developed by the Transportation Research Board of the National Research Council, USA. Report 350 is entitled “Recommended Procedures for the Safety Performance Evaluation of Highway Features”. The standard describes how impact tests are to be carried out and the result determines a working width expressed in metres. This standard is used mainly in the USA.