A Comprehensive Guide to Rear-Facing Car Seats
The Science of Why Rear-Facing Matters
Rear-Facing: The Safer Choice
Rear-facing is the safest travel mode for children – recognized for its critical role in protecting against severe head and spinal injuries.
The American Academy of Pediatrics (AAP) strongly recommends that children ride in a rear-facing car seat for as long as possible, guided by the height and weight limits set by the car seat’s manufacturer. This generally includes all toddlers under age 2, and extends to the majority of children until they are approximately 4 years old.
This recommendation is rooted in a comprehensive understanding of developmental needs and the physics of vehicle collisions, aiming to ensure the highest level of safety for our most vulnerable passengers and their unique vulnerabilities during vehicle collisions.
Optimizing Safety with Correct Car Seat Use
To maximize safety, it’s important that rear-facing car seats are used correctly. Key guidelines include:
- Positioning the harness straps at or below the child’s shoulders.
- Adjusting the chest clip to armpit level and ensuring the harness is snug.
- Following the manufacturer’s instructions for appropriate seat angle and correct belt path installation.
- Maintaining a minimum of 1 inch of the seat shell above the child’s head.
- Opting for either Lower Anchor or Seat Belt installation, not both, unless manufacturer specified otherwise.
- Achieving a tight install, with no more than 1 inch of movement at the belt path.
Adhering to specific car seat and vehicle manual instructions is crucial for safety.
The Science of Crashes
Collision Dynamics and Impact
The nature and direction of a crash significantly influence a car seat’s protective capabilities. Frontal and offset-frontal collisions, which are the most common types of vehicular collisions, emphasize the criticality of rear-facing seats in mitigating risks associated with frontal impacts. Rear-facing car seats are specifically designed to excel in protecting against these crashes, which are more likely to result in serious injuries.
Continue reading to understand why the point of impact is a critical factor in the protective effectiveness of rear-facing car seats.
The Three Collisions in a Crash
During a crash, all occupants and objects within a vehicle are propelled toward the point of impact. A vehicular crash unfolds in three stages:
- The Vehicle Crash: The initial collision where the vehicle’s structure absorbs some impact forces.
- The Human Crash: Occupants continue moving at the vehicle’s pre-collision speed until halted by a restraint system.
- The Internal Crash: Even after the body stops, internal organs may continue moving, leading to potential internal injuries.
Crash Force Distribution
The amount of force needed to bring an occupant to a complete stop during a crash depends on the occupant’s weight and the speed they are moving. For example, a 10-pound infant traveling at 30 MPH would require around 300 pounds of restraining force to bring them to a stop.
When a child is seated rear-facing during a frontal crash, the forces are spread across the entire body, including the head, neck, and back. The child is encased by the protective shell of the car seat, and the head moves in unison with the seat, significantly reducing the risk of severe neck and spinal injuries.
Conversely, in a forward-facing position, the harness secures only the child’s torso, allowing the head to jolt forward. This sudden movement places intense force on the child’s neck, leading to a higher risk of head and spinal injuries.
The Anatomical and Developmental Basis for Rear-Facing
The Developing Spine
The human spine is composed of 24 presacral vertebrae, categorized into 7 cervical (neck), 12 thoracic (upper back), and 5 lumbar (lower back) vertebrae. In young children, these vertebrae are made up of bone segments connected by cartilaginous joints known as synchondroses, rather than fully ossified bone. This developmental stage leaves them particularly vulnerable to spinal injuries in crashes when seated forward-facing.
Over time, these cartilaginous segments gradually ossify, fusing together. By age 3, there’s only a 50% chance that the C3 vertebra has fully ossified. As children grow older, their spinal columns become stronger, achieving complete ossification around the age of 6. Because younger children’s vertebrae are still developing, their spinal cord does not have adequate protection in the event of a crash.
When a child is seated facing forward during a frontal collision, the force exerted on their immature skeletal structure can cause the spinal cord to stretch up to 2 inches; serious injury can occur with just a 1/4 inch stretch. This extreme stretching can lead to severe cervical spine injury.
When a child is seated rear-facing in a frontal crash, the car seat helps decelerate the child’s body by distributing crash forces across the entire back of the seat, utilizing the largest possible surface area to absorb the impact, thereby enhancing safety and minimizing injury risk. In contrast, when seated forward facing, crash forces are instead concentrated only on the harness points at the shoulders and pelvis.
The Proportionate Head Size
In addition to having underdeveloped skeletal and neck structures, infants and toddlers have a larger head-to-body ratio compared to older children. Consequently, in a crash, younger children who are forward-facing experience more significant forces impacting their head and neck than older children. In such a setup, while the child’s torso is secured by harness straps, the head remains unrestrained and can jerk forward violently, potentially causing severe spinal injuries or even death.
Additionally, rear-facing child restraints provide enhanced safety benefits during side and frontal offset impacts. When a child is rear-facing in these types of collisions, their head remains better contained within the protective shell of the seat, maximizing the benefit from the seat’s side impact protection mechanisms.
TL;DR
Rear-facing car seats are the safest travel option for children, significantly reducing the risk of head and spinal injuries in crashes by distributing the forces of a crash across the entire back of the seat. The American Academy of Pediatrics recommends keeping children in rear-facing seats as long as possible within the manufacturer’s height and weight guidelines. Proper installation and adherence to the car seat manufacturer’s instructions are crucial for ensuring safety. The anatomical and developmental stages of young children make them particularly vulnerable in forward-facing seats, further underscoring the benefits of rear-facing configurations. It is safe for a child’s legs to touch the vehicle seat back, and this position is generally comfortable due to their flexibility. Rear-facing seats also provide enhanced protection in rear-end and side collisions. The science is clear: rear-facing car seats provide the best defense against the most common and devastating types of vehicle collisions.
FAQs on Rear-Facing Car Seat Safety
No, it is not unsafe. Only a very small number of children in rear-facing seats sustain lower extremity injuries, a rate significantly lower than those facing forward. Children are naturally flexible and can comfortably accommodate their legs touching the back of the vehicle seat. The potential for leg fractures is far less critical than injuries to the neck or spinal cord, which are more common in forward-facing scenarios.
Children generally do not find rear-facing leg positions uncomfortable due to their inherent flexibility. They benefit from being able to sit in various positions such as criss-crossed, legs over the sides, or pulled up. In contrast, children often express discomfort with their legs dangling when forward-facing, as they cannot easily shift positions.
If visibility is a concern, consider positioning the car seat on the passenger side for easier access and reach when stopped. Additionally, a lightweight, securely attached mirror with a soft frame can be used, though it’s essential to ensure it doesn’t pose a projectile risk or distract from driving. Never install the car seat in the front row or in front of an active airbag. For added safety, avoid allowing your child to eat, drink, or play with small toys during the ride to prevent choking hazards, especially when you can’t easily see them.
If your child becomes upset because they can’t see you, remember this isn’t a direct safety issue but can be distressing. Having a companion in the backseat or timing travel with nap times can help manage separation anxiety and keep the child engaged. If the child tends to vomit from excessive crying, try not to travel immediately after meals and consider taking frequent breaks. Understanding that separation anxiety is often temporary may also be comforting; children typically learn that you will return at the end of the ride, which can ease their stress.
Despite some concerns, rear-facing car seats provide substantial protection even in rear-end collisions, which only account for a small fraction of severe and fatal crashes.
Rear-facing seats provide superior protection in the most common and severe crash types, including frontal, side, and offset impacts. Even in the case of a rear-end collision, rear-facing children are not at a disadvantage.
The nature of rear-end crashes typically results in less intense crash forces. These collisions are especially common in urban settings with dense traffic and frequent stops, usually occur at lower speeds and are less likely to be severe. In fact, frontal and side impacts are far more common and typically more severe. The dynamics of the majority of rear-end impacts do not pose the same level of threat as those from frontal or side impacts.
The design and positioning of rear-facing seats provide robust protection, making them the safer option for nearly all vehicular crashes.
In side-impact collisions, rear-facing car seats generally offer better protection than forward-facing ones. This superior safety is largely due to how these seats manage collision forces. In many side impacts, there are also frontal forces involved, which means that the collision is not strictly lateral but includes a forward motion. For children in rear-facing seats, this means that their movement during a collision is contained within the protective shell of the car seat, greatly reducing the risk of injury. This design ensures that the child remains within the confines of the seat’s protective barriers, protecting them against contact with the vehicle interior or external intrusions.
In contrast, children in forward-facing seats face greater risks in similar conditions. Their heads and upper bodies can extend beyond the protective confines of the car seat during a collision, increasing their likelihood of contact with parts of the vehicle or crash intrusions. This is particularly problematic in frontal-offset components of side impacts, where forward-facing children can be thrust forward and sideways, moving away from the protective features like head support or seat shell. Conversely, a rear-facing child will move deeper into the car seat’s shell, which acts as a buffer against these forces.
Although a purely lateral side impact might not show a significant difference in protection between the two orientations, such scenarios are uncommon. Most side impacts include frontal forces, making rear-facing seats significantly safer. Given this, rear-facing car seats are recommended for as long as possible to ensure optimal protection in a variety of collision scenarios.