Research results

Research Results Presentation Wire Rope Guardrail System in Practical Use

  A newly developed wire rope guardrail

  Tempoku Pass on National Highway 275

  A rubber delineator

  In November 2012, Japan's first Wire Rope Guardrail System was installed on a 1.6km section of the Hokkaido Expressway between Onuma-koen IC and Mori IC. In the following month, such guardrails were also installed on a 320m section of National Highway 275 at Tempoku Pass in Otoineppu Village. In addition to these examples from Hokkaido, such guardrails were installed on a 128m section of the Kisei Expressway between Kisei-Ouchiyama IC and Kii-Nagashima IC, and on a 390m section of the Joban Expressway between Yasuda IC and Mikawa IC. These guardrails are expected to have a great effect on preventing serious traffic accidents.

  Wire rope guardrails substantially differ from conventional guard cables, in that the support pillars deform when a vehicle hits them and the wire ropes absorb the impact to mitigate damage to the vehicle and harm to the passengers. Thin support pillars allow them to be installed on relatively narrow roads and on existing roads. Furthermore, the wires and pillars are easily separable by hand, which enables prompt separation of ropes from the pillars to make openings for emergency vehicles. Also, such guardrails rarely suffer permanent deformation from snow removal and snow does not accumulate at the guardrails such that it narrows the lane and impedes traffic. The latest development was a rubber delineator that cushions crashing vehicles and avoids dispersion of their parts, causing no further casualty from accident.

  Wire rope guardrails were patented in 2012. They have received awards from many academic societies in recognition of their technological uniqueness and high practicality.

  The team plans to work closely with road management authorities to study the guardrails installed on the roads to find out how to improve their specifications, as well as their construction and management methods. The team will summarize these studies in an installation guideline.

(Contact: Traffic Engineering Research Team, CERI)