Salvaged and/or re-galvanized guardrail on construction projects

Arizona DOT uses salvaged guardrail in some cases.
Under what circumstances will the state agency authorize its use? – When the guardrail is in good condition, but the height will be out of spec due to the overlay thickness. In that instance, crews may remove and replace with the salvaged guardrail.
How does the state agency verify and certify that the salvaged and/or re-galvanized guardrail meets state specifications? – They use the guardrail that was originally at the location, which met state specifications. They do not allow contractors to bring in salvaged guardrail for new installations.
How long has the state agency allowed the use of salvaged and/or re-galvanized guardrail? – Many years.
How is it documented that using salvaged and/or re-galvanized guardrail will result in significant savings? – Just the fact that the existing guardrail is reused with new hardware obviously saves the cost of new guardrail.