KDOT Guardrail, Barriers & Safety Appurtenances

Question 1

What is the standard height of W-beam guardrail from finished grade to the top of the rail?

Accepted Answer

27¾ inches

Answer

AASHTO and KDOT standards specify W-beam guardrail top height at 27¾ inches from finished grade for effective vehicle redirection.

Question 2

Which crash test manual currently governs acceptance of roadside safety hardware on KDOT projects?

Accepted Answer

AASHTO MASH

Answer

The Manual for Assessing Safety Hardware (MASH) has replaced NCHRP 350 as the required crash test standard for roadside safety hardware on federal-aid projects including KDOT work.

Question 3

When inspecting guardrail post installation, what must be verified about posts driven into soil?

Accepted Answer

Posts must be set plumb and at the correct embedment depth per plans

Answer

Guardrail posts must be installed plumb and at the specified embedment depth per KDOT plans to ensure the system performs as designed during an impact event.

Question 4

What type of end treatment is required at the approach end of a guardrail run where traffic may directly impact the terminal?

Accepted Answer

MASH-compliant flared terminal

Answer

Approach ends of guardrail must be equipped with MASH-compliant flared terminals to safely redirect or absorb impacting vehicles rather than creating a spear-like hazard.

Question 5

What is the standard post spacing for W-beam strong-post guardrail systems?

Accepted Answer

6 feet 3 inches

Answer

The standard post spacing for strong-post W-beam guardrail is 6 feet 3 inches (75 inches) center to center as specified in AASHTO guidelines adopted by KDOT.

(KDOT) Certified Kansas Department of Transportation Inspector Practice Test

(KDOT) Certified Kansas Department of Transportation Inspector Practice Test

KDOT Guardrail, Barriers & Safety Appurtenances