CPST Harness Systems and Harness Fit 2 — Questions and Answers
Question 1: The crotch buckle strap on a car seat should be adjusted to the slot closest to the child primarily to:
- Make buckling easier for the caregiver
- Prevent the child from submarining under the harness in a crash (Correct answer)
- Allow the child to sit more comfortably
- Accommodate the child's leg length
Correct answer: Prevent the child from submarining under the harness in a crash
Positioning the crotch strap in the closest slot keeps the harness snug across the hips and prevents forward slide (submarining) during a crash.
Question 2: Twisted harness webbing is a safety concern because it:
- Makes the harness more difficult to tighten quickly
- Reduces webbing strength and can concentrate crash forces on a narrow band (Correct answer)
- Causes premature wear on the seat shell
- Prevents the chest clip from staying in position
Correct answer: Reduces webbing strength and can concentrate crash forces on a narrow band
Twisted straps reduce effective webbing width and strength, concentrating crash loads and potentially cutting into the child instead of distributing force.
Question 3: What clothing is most appropriate for a child to wear in a car seat in cold weather?
- A thick down snowsuit for maximum warmth
- A heavy fleece jacket for insulation
- Thin layers with a blanket placed over the buckled harness (Correct answer)
- A bulky sweater to provide padding in a crash
Correct answer: Thin layers with a blanket placed over the buckled harness
Thin layers allow the harness to fit snugly; a blanket placed over the already-buckled harness adds warmth without creating dangerous slack.
Question 4: When a harness shoulder strap repeatedly slides off a child's shoulder, the most likely cause is:
- The harness is tightened too much
- The harness slots are at the wrong height for the child (Correct answer)
- The chest clip is positioned too low
- The crotch buckle slot is incorrect
Correct answer: The harness slots are at the wrong height for the child
Straps falling off the shoulder indicate the harness slot is set too high or the wrong slot is selected; adjusting to the correct slot height keeps straps on the shoulders.
Question 5: Why are aftermarket harness accessories (such as strap covers or added padding) generally not recommended by CPSTs?
- They are too expensive for most families
- They have not been crash-tested with the specific seat and may alter harness performance (Correct answer)
- They are only approved for seats manufactured after 2015
- They are permitted only for forward-facing seats
Correct answer: They have not been crash-tested with the specific seat and may alter harness performance
Aftermarket products are not tested with specific car seats; they can change harness geometry and energy absorption in ways not approved by the manufacturer.
Question 6: During a harness check, a technician is unable to tighten the harness because the adjuster strap is frayed. What is the appropriate recommendation?
- Reinforce the adjuster with duct tape until a replacement is available
- Contact the manufacturer and potentially replace the seat (Correct answer)
- Use the LATCH strap as an additional tightening point
- Tie a knot in the adjuster webbing to shorten it
Correct answer: Contact the manufacturer and potentially replace the seat
A damaged harness adjuster is a mechanical safety defect; the family should contact the manufacturer and may need to replace the seat.
Question 7: What is the practical difference between a front-pull (no-rethread) harness adjuster and a rear-pull harness adjuster?
- Front-pull adjusters are only found on infant seats
- Rear-pull adjusters require the child to be removed from the seat to retighten (Correct answer)
- Front-pull adjusters cannot be used with the LATCH system
- Rear-pull adjusters provide a tighter harness in a crash
Correct answer: Rear-pull adjusters require the child to be removed from the seat to retighten
Rear-pull adjusters are routed behind the seat back, requiring the child to be lifted out each time the harness needs to be tightened or loosened.
CPST Harness Systems and Harness Fit 2
The crotch buckle strap on a car seat should be adjusted to the slot closest to the child primarily to: