Guardrail Deflection Analysis – Phase I (405160-24)

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Final Report Link: Guardrail Deflection Analysis:  Phase I


Guardrail Deflection Analysis Spreadsheet referenced in the above report.

TTI Research Supervisor:
Akram Abu-Odeh, Ph.D.
Texas Transportation Institute
Texas A&M University System
TAMU 3135
College Station, Texas 77843-3135
(979) 862-3379
[email protected]
Pooled Fund Technical Representative:
Dave Olson
Design Policy, Standards and Research Manager
Washington State Department of Transportation
P.O. Box 47329
Olympia, WA 98504-7329
[email protected]


This research syntheses the deflection of several guardrail systems to help roadway designer select appropriate system for a desired deflection need.

Fifty-three full scale crash test reports were reviewed to tabulate guardrail deflection. The tests were performed in five categories:

  1. Single 12 gauge W-beam rail (35 systems)
  2. Thrie beam rail (6 systems)
  3. Nested rail (2 systems)
  4. 13 gauge rail (1 system), and
  5. W-beam rails designed for special applications (9 systems).

Salient design features if the tabulated included rail height, post size, post material, post spacing, block out, and test designation. The tables present maximum permanent and dynamic deflections, working with width if available. A spreadsheet was developed with this information as a useful tool to engineers to look these guardrail data in order to select appropriate guardrails for the desired maximum deflection.

Weak Post W-beam
Strong steel post W-beam
Strong wood post W-beam
Strong post thrie-beam (G9-S) Modified thrie-beam
Strong post with steel post guardrail (G4(1S))
Weak post W-beam guardrail (G2)


Not applied.


Not available.