A slotted rail terminal (SRT) for W-beam guardrails was successfully developed and crash-tested in accordance with requirements set forth in NCHRP Report 230. The SRT design is intended as a retrofit or replacement of the standard breakaway cable terminal (BCT) and has better impact performance than the eccentric loader terminal and the modified eccentric loader terminal. The slotted rail concept involves cutting three longitudinal 12.7 mm (1/2 in.) wide slots into the W-beam rail, one at each peak and valley in the cross section, to reduce the buckling strength while maintaining the tensile capacity. The reduced buckling strength of the slotted rail allows for controlled buckling of the rail, which greatly reduces the yaw rate of the impacting vehicle, thereby minimizing the potential for the buckled rail to directly contact or penetrate the occupant compartment. The SRT terminal is expected to be less sensitive to installation details because the buckling of the rail is controlled by the slots and is at a force level substantially lower than the unmodified W-beam rail. A slot guard is attached to the downstream end of each set of slots to prevent extension of the slots and rupture of the rail. To help reduce inventory and control cost, the SRT terminal uses many of the standard components used with the BCT and other flared terminals. In addition, the layout and configuration of the SRT terminal is similar to that of the standard BCT terminal to facilitate easy retrofit.


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Media Info

  • Features: Figures; Photos; References; Tables;
  • Pagination: p. 43-51
  • Monograph Title: Geometric design, roadside safety features, roadside hardware monitoring, and scenic loop tours
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00714990
  • Record Type: Publication
  • Files: TRIS, TRB
  • Created Date: Dec 26 1995 12:00AM