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

24 inches

Answer

31 inches

Answer

36 inches

Question 2

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

Accepted Answer

AASHTO MASH

Answer

NCHRP Report 350

Answer

FHWA Circular No. 5040.8

Answer

MUTCD Chapter 6

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

Post depth must equal post height above ground

Answer

Posts must be filled with concrete grout

Answer

Posts must be painted safety yellow for visibility

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

Blunt end with retroreflector

Answer

Turned-down end anchored to the ground

Answer

Concrete anchor block only

Question 5

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

Accepted Answer

6 feet 3 inches

Answer

3 feet 1½ inches

Answer

10 feet

Answer

12 feet 6 inches

Question 6

During guardrail installation inspection, which splice orientation defect requires immediate correction?

Accepted Answer

Rail sections lapped in the wrong direction relative to traffic flow

Answer

Rail sections showing minor surface rust at the splice

Answer

Splice bolts that are slightly overtightened

Answer

Rail stored on wooden pallets before installation

Question 7

What is the purpose of the offset block (blockout) used between the W-beam rail and the guardrail post?

Accepted Answer

To move the rail face away from the post and allow the system to deflect properly during impact

Answer

To increase the decorative appearance of the guardrail

Answer

To reduce the installed height of the rail to AASHTO standards

Answer

To provide electrical insulation between the post and rail