Identification, Analysis, and Remedial Treatment of Low Guardrail in Virginia

About the report:

Guardrails that are too low may fail to safely redirect errant vehicles; instead, the vehicles may vault the guardrails, resulting in severe accidents. An analysis of data on a small sample of guardrails throughout Virginia showed that over 80% of the guardrails were lower than the current standard height of 27 in. The causes of low guardrail were identified as installation at old standards that were lower than current standards, faulty installation, and inadequate maintenance. Methods for locating low guardrails were identified and six remedial treatments were developed ranging from removal of the guardrail to complete reinstallation. A numerical scoring system was developed whereby correction of low guardrails may be prioritized according to the degree of hazard presented by the low guardrail. The scoring system employs an equation based on the guardrail performance variables considered to be most important; namely, guardrail height, vehicle speed, and expected number of encroachments. Additional factors that can affect the degree of hazard but were not included in the equation are guardrail type, consequences of vaulting, and soil type. Provision were made for increasing total scores or situations in which these variables are important.

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