CDT Traffic Laws & Road Safety Rules 2

Question 1

Under federal regulations, what is the maximum allowable blood alcohol concentration (BAC) for a CDL holder operating a commercial vehicle?

Accepted Answer

0.04%

Answer

Federal law sets the BAC limit for CDL drivers operating CMVs at 0.04%, half the limit for non-commercial drivers.

Question 2

A driver trainer notices a student hesitates before entering a roundabout. Which is the correct rule for yielding in a roundabout?

Accepted Answer

Entering vehicles yield to vehicles already circulating inside

Answer

Vehicles entering a roundabout must yield to all traffic already circulating within it.

Question 3

A school bus has stopped with red lights flashing on a two-lane undivided road. What must the following vehicle do?

Accepted Answer

Stop at least 20 feet away and wait until the lights stop flashing

Answer

All vehicles on both sides of a two-lane road must stop at least 20 feet from a stopped school bus with flashing red lights.

Question 4

What does a yellow X signal above a lane on an expressway indicate to drivers?

Accepted Answer

Move out of the lane — it is closing or closed

Answer

A yellow X warns that the lane is about to close; drivers should move to an adjacent open lane immediately.

Question 5

When must a driver use low-beam headlights instead of high beams while following another vehicle?

Accepted Answer

Within 500 feet

Answer

Most states require drivers to dim high beams to low beams when following another vehicle within 500 feet to avoid blinding the driver ahead.

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