Crash Dynamics and Misuse Flashcards

If a vehicle's speed doubles from 30 mph to 60 mph, by what factor do the crash forces increase?

Answer: They quadruple (4x).

Crash forces are related to kinetic energy, which is proportional to the square of the velocity. When the speed doubles, the forces involved in a crash increase by a factor of four (2 squared). This physical principle is why small increases in speed have a dramatic effect on crash severity and the importance of restraints.

A caregiver has added a thick, plush harness strap cover and a separate head support pillow to their infant's car seat, which were purchased online. What is the primary safety concern a CPST must address?

Answer: These non-regulated aftermarket products can interfere with proper harness tightness and placement, creating slack and compromising protection in a crash.

Aftermarket products—those not sold with the car seat or specifically approved by the car seat manufacturer—are not crash tested with the seat. They can introduce slack, change how the harness lies on the child, or interfere with the seat's performance, all of which can lead to catastrophic failure in a crash.

The primary safety principle of 'riding down the crash' is best achieved under which of the following conditions?

Answer: A tightly installed car seat with a snug harness, coupling the child to the vehicle's structure.

Riding down the crash refers to the process of an occupant slowing down with the vehicle itself. A tightly installed car seat and a snug harness ensure the child is connected to the car's frame, allowing them to benefit from the vehicle's crumple zones which are designed to absorb crash energy over a slightly longer period, thus reducing the peak forces on the occupant.

A caregiver receives a used car seat from a neighbor. Which of the following represents the MOST critical reason to advise against using it?

Answer: The complete history of the car seat, including any potential crash involvement, is unknown.

A car seat's crash history is the most critical piece of information. A seat that has been in a moderate to severe crash may have unseen structural damage that compromises its ability to protect a child in a future collision. Without knowing the full history, the seat's integrity cannot be guaranteed, making it unsafe to use.

A CPST observes that a newborn in a rear-facing car seat is positioned too upright, causing their head to slump forward with their chin on their chest. What is the primary danger associated with this misuse?

Answer: It can lead to positional asphyxia by obstructing the infant's airway.

Newborns and young infants have weak neck muscles and a disproportionately heavy head. If the recline angle is too upright, the head can fall forward into a 'chin-to-chest' position, which can partially or fully block their fragile airway, leading to positional asphyxia (suffocation). This is a risk both during driving and if the infant is left to sleep in the seat outside the vehicle.

A child is riding in a forward-facing car seat with the harness chest clip positioned low over their abdomen. In a frontal crash, what is the most likely and dangerous consequence of this specific misuse?

Answer: The harness straps can slip off the child's shoulders, increasing the risk of upper body excursion or ejection.

The chest clip's function is to properly position the harness straps over the child's strong collarbones before a crash. If the clip is too low, the straps can spread apart and slip off the shoulders during the forces of a collision, which could allow the child's upper body to be thrown forward or even be ejected from the restraint.