Child restraints and road safety

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 PROTECT YOUR FAMILY: A proper seatbelt restraint for your infant is a necessity. Image: Shutterstock ~ Shutterstock

Ejection from a vehicle is one of the most injurious events that can happen to a person in a crash, with 75% of all vehicle occupants ejected from a vehicle in a crash dying as a result.
Seatbelts are effective in preventing ejections: overall, 44% of unrestrained passenger vehicle occupants killed are ejected, partially or totally, from the vehicle, as compared to only 5% of restrained occupants.
Seatbelts are approximately 50% effective in preventing fatalities in crashes in which motorists would otherwise die. It is estimated that seatbelt use prevented about 15 200 deaths in the United States in 2004. If all passenger vehicle occupants over 4 years of age in the United States had used seatbelts in 2004, nearly 21 000 lives could have been saved (that is, an additional 5800 lives).
A review of various United States studies has shown that child safety seats that are correctly installed and used for children aged 0–4 years can reduce the need for hospitalisation by 69%.
The risk of death for infants is reduced by 70% and that for children aged 1–4 years by 47–54%. Of children aged under five, 485 lives could have been saved in the United States in 2002 if all the children had been in child safety seats.
It has been estimated in the United Kingdom that new rules on the use of child restraints rather than adult seatbelts for children up to
135 cm in height or aged 12 years and above will save over 2000 child injuries or deaths every year. It is estimated that within the European Union seatbelts currently reduce driver fatalities by 40%.
Wearing rates in European countries vary widely from around 70% to over 95%. If all European Union countries were to achieve a 99% wearing rate for drivers, 2400 lives would be saved each year.

In many high-income countries the use of child restraints is common – with usage rates up to 90% – but in other countries they are still rarely used.

Understanding the way seatbelts work

Seatbelts and child restraints are secondary safety devices and are primarily designed to prevent or minimise injury to a vehicle occupant when a crash has occurred. Seatbelts and child restraints thus:

    reduce the risk of contact with the interior of the vehicle or reduce the severity of injuries if this occurs;
    distribute the forces of a crash over the strongest parts of the human body;
    Increasing use of vehicles worldwide has brought more crashes and injuries to vehicle occupants, particularly in low- and middle-income countries;
    prevent the occupant from being ejected from the vehicle in an impact;
    prevent injury to other occupants (for example in a frontal crash, unbelted rear-seated passengers can be catapulted forward and hit other occupants).


Infants and children need a child restraint system that accommodates their size and weight, and can adapt to cope with the different stages of their development. The three-point lap and diagonal seatbelt used by adults is not designed for children’s varying sizes, weights, and the different relative proportions of children’s bodies.

For example, a smaller portion of a child’s abdomen is covered by the pelvis and rib cage, while a child’s ribs are more likely than an adult’s to bend rather than break, resulting in energy from a collision being transferred to the heart and lungs. Consequently three-point lap and diagonal seat-belts may lead to abdominal injuries among children, and will not be optimally effective at preventing ejection and injury among them.

Appropriate child restraint systems are specifically designed to protect infants and young children from injury during a collision or a sudden stop by restraining their movement away from the vehicle structure and distributing the forces of a crash over the strongest parts of the body, with minimum damage to the soft tissue. Child restraints are also effective in reducing injuries that can occur during non-crash events, such as a sudden stop, a swerving evasive manoeuvre or a door opening during vehicle movement.

The safest place for children aged 12 years and under is in the back seat, properly restrained in an approved child safety seat. Specially manufactured child restraints should be used for children.


    It is the second collision that is most responsible for injuries, and can be reduced significantly by the use of seatbelts and child restraints. The most frequent and most serious injuries occurring in frontal impacts to occupants unrestrained by seatbelts are to the head, followed in importance by the chest and then the abdomen. Among disabling injuries, those to the leg and neck occur most frequently.

    When a crash occurs, a car occupant without a seatbelt will continue to move at the same speed at which the vehicle was travelling before the collision and will be catapulted forward into the structure of the vehicle – most likely into the steering wheel if they are driving, or into the back of the front seats if they are rear seat passengers. Alternatively, they can be ejected from the vehicle completely.

    At birth, the infant head is around a quarter of their total length and about a third of their body weight. An infant’s skull is very flexible, so a relatively small impact can result in significant deformation of the skull and brain. The smaller the child, the lower the force needed for injury. The infant rib cage is also very flexible. Impact to the chest can result in a large compression of the chest wall onto the heart and lungs and some of the abdominal organs. The infant pelvis is unstable and cannot withstand the forces from an adult restraint system. Infants require their own special seat designed to cradle them in a crash, and provide protection from many types of crashes.

    Like adult seatbelts, child restraints in cars are intended to keep a child firmly secured in their seat so that in the event of sudden braking or collision the child is not thrown against the car interior or ejected from the vehicle. The restraint must absorb kinetic energy (created by the motion of the child during the crash) without itself injuring the child and must be easy to use.

    Choosing the correct child restraints

    There are a number of different types of restraints - The main determining factor for choice of a child restraint is the child’s weight. Older children who are above the height and weight specifications for using child restraints require a properly fitting three-point lap and diagonal seat-belt when riding in a vehicle.

    It is also important that child restraints be used correctly – If a child is restrained in the wrong system for its age or weight, or the straps or harnesses are not adequately secured or entirely left undone, it will place the child at an increased risk of both fatal and non-fatal injuries. Always follow the manufacturer’s instructions when installing a restraint and placing your child in it.

Different Ages Groups and Child Restraints

    Child restraints are designed to match a child’s height and weight. When you buy a restraint you need to consider:
        The size and weight of your child.

        There are three “collisions” that occur in every crash where occupants are unrestrained. The first collision involves the vehicle and another object, e.g. another vehicle(s), a stationary object (tree, signpost or ditch) or a human or animal. The second collision occurs between the unbelted occupant and the vehicle interior, e.g. the driver hits his chest on the steering wheel or his head on the window. Finally, the third collision occurs when the internal organs of the body hit against the chest wall or the skeletal structure.

        The child should be kept in the most appropriate restraint suitable for his or her size and age and only be moved to the next category of restraint when he or she no longer physically fits.
            Infant: Birth-1 Year

        Never carry your child in your arms or share your seat belt with your child. In a crash you won't be able to hold on to your child. He or she may be thrown around the vehicle or thrown out of the vehicle. The safest way for an infant to travel in a vehicle is in the rear facing position. A rear-facing child restraint system (sometimes called an “infant car seat”) provides the best protection for infants until they are 1 year of age. Keep them in this position for as long as possible and only move them to a forward facing child seat when they no longer fit in the rear facing position.
            Children aged 1–4 years

        The bone-forming process is not complete until the age of 6 or 7 and throughout childhood a child’s skull remains less strong than that of an adult. A restraint system needs to limit forward head movement in a frontal impact and provide protection from intrusion in a side impact. A child restraint should therefore distribute the crash forces over as wide an area as possible. Belts and harnesses need to fit well and be properly positioned as designed by the manufacturer.

        The restraint system should also provide protection from contact with the vehicle interior in both front and side impacts. The best type of child restraint for young children is the child safety seat. The integral harness secures the child and spreads the crash forces over a wide area. This seat will last them until either their weight exceeds 18kg or they grow too tall for the height of the adjustable harness.
            Children aged 4–6 years

        Booster seats are best used only when a child has outgrown a safety seat. They are designed for weights from 15 kg to 25 kg. Children should continue to ride in a booster seat until the lap and diagonal belts in the car fit properly, typically when they are approximately 145cm tall. Booster seats raise the seating position of the child so that the adult seat-belt lies properly across the chest, crossing diagonally at the child's shoulder rather than the neck, and low across the pelvis. If the adult belt is too high across the stomach, in a crash serious internal injury could result, or the child could submarine under the seat-belt. The booster seat has a back and can provide some protection in a side impact.
            Children aged 6–11 years

        A booster seat can improve the seat belt fit when your child is too big for a forward facing child seat and too small for an adult belt. As a general guide, buy a rigid booster seat with a back, side wings and a sash guide to keep the seat belt in place.

        Booster cushions without backs are designed for weights from 22kg to 36kg, but manufacturers are now producing booster cushions with backs that cover the full 15kg to 36kg range. Shield booster seats, which have a plastic shield in front of the child, offer less protection and should not be used.

        It should also be noted that although children are best protected when secured in age appropriate child restraints, if such restraints are not available, it is still better to use an adult seat-belt on the child than leave the child unrestrained on the back seat.

        Once your child’s eyes are level with the top of the back seat of the car or the child is approximately 26kg or over, they may use a seatbelt. The seat belt, however, must fit your child correctly; i.e. the lap belt is low over the bony part of the hips (not the stomach) and the sash does not touch their face or neck when all slack is removed.