During a vehicle inspection, a driver finds that one-fourth or more of the leaves in a leaf spring are missing or broken. What is the correct classification of this defect?

49 CFR 393.207 (suspension systems — prohibits cracked, broken, missing, or shifted leaf springs, but sets no numeric fraction); the specific 'one-fourth or more leaves missing' out-of-service threshold comes from CVSA's North American Standard Out-of-Ser

The suspension holds the axles in their proper position; losing a quarter or more of a leaf spring's leaves can let an axle shift out of alignment during driving, risking loss of control. This is one of the specific numeric out-of-service thresholds the knowledge test expects drivers to know exactly, not approximately.