Basics of Using Safety Belts
 
updated 09-08-06

How Safety Belts Prevent Injury
Occupant restraint systems are designed to reduce injury to occupants and help to do so five different ways. Safety belts, air bags and child restraints are designed to:

1. Prevent ejection - People thrown from a vehicle are four times more likely to be killed than those who remain inside. Ejected occupants are also 14 times as likely to sustain cervical spine injury than those who remain within the vehicle.

2. Load crash forces on the strongest parts of the body - For an older child or adult, these parts are the hips and shoulders. For an infant and young child, there is really no part strong enough, so the restraint supports the entire body to avoid stress on any one part.

3. Spread crash forces over a wide area of the body - This puts less stress on any one part of the body. Lap and shoulder combination safety belts and child restraint harnesses spread the crash forces across a large area of the body. A rear-facing infant restraint spreads the force along the entire back, neck and head.

4. Allow the body to slow down gradually - Vehicles are engineered to crush in a controlled manner. Occupants can take advantage of the vehicle ride down only if they become a “part” of the vehicle using a snug safety belt or CRS.

5. Protect the head, neck, and spinal column - A shoulder belt or CRS harness helps to keep the head and upper body away from the hard interior surfaces of the vehicle. A rear facing child restraint supports the head and neck to avoid stress on the neck and trauma to the head and spinal cord.

Unsurvivable Crashes
Some crashes are so violent that even properly restrained occupants are injured or killed. Factors such as the size, weight, speed and direction of the vehicles involved in the impact will affect the outcome. If the occupant compartment is crushed, restraints may be unable to prevent injury or death.

However, probabilities and statistics cannot predict what will happen in every crash. A variety of factors determines injury outcome. Safety belts and child restraint systems are designed to protect against the type of crash forces most likely to occur. The best way to avoid or reduce injury is to restrain the body in the most effective way possible.

Types of Safety Belts
Lap belts - The lap belt is a "2-point" belt that has two anchorage points and fits over the lap (upper thighs/hips). Its primary benefits are to prevent ejection and to keep the occupant from being thrown around inside the vehicle striking other occupants or unforgiving surfaces. The lap belt does not restrain the upper body.

A lap belt should be as snug as possible and at least touching the upper thighs. In this position the crash forces will be loaded on the hips. If the lap belt is too loose, the occupant can "submarine" under the lap belt.

In a crash, seat belt syndrome occurs if a lap belt is worn over or rides up on the abdomen rather than the hipbones causing injuries to the lower spine and organs such as spleen, liver and intestines.

Lap and shoulder combination belt - The lap and shoulder combination belt is a "3-point" belt that has three anchorage points. The shoulder belt provides restraint for the upper chest and shoulders. When positioned correctly, the shoulder belt reduces head excursion, helping to reduce brain and spinal cord injury. The shoulder belt must lie across the collarbone as close to the neck as possible without being uncomfortable.

Placing the shoulder belt under the arm or behind the back is very dangerous. Doing so increases the risk of belt-induced internal injuries in addition to not providing any upper body restraint.

Some of these belt systems are manufactured as one long continuous piece of belt webbing and others are comprised of two separate pieces of webbing. Shoulder belts have been required in front seats since 1973. Rear outboard shoulder belts have been required since 1989. A phase in for requirements that all rear seat positions, including center-rear, be equipped with lap and shoulder belts began with model year 2006 (manufactured September 1, 2005 through August 31, 2006). Beginning with model year 2008 (manufactured on or after September 1, 2007) all vehicles, must equip all rear seat positions with lap and shoulder combination safety belts.

Importance of Correct Fit
The importance of a correct fit of safety belts is often overlooked. However, a safety belt can not provide maximum protection if it is not worn correctly. The shoulder belt should cross the shoulder between the neck and arm and the lap belt must be as low as possible and at least touching the thighs.

Add-on shoulder belt adjusters are not recommended since they are not covered by any Federal standards and may, in fact, do more harm than good. Never tuck the shoulder belt under the arm or behind the back. Placing the shoulder belt under a child’s (or adult’s) arm or behind the back is dangerous and is illegal in North Carolina.

NC Legal Requirements
North Carolina law requires, as of December 1, 2006, that all drivers and occupants of any age be restrained by a properly fitted safety belt or child restraint. Furthermore, most children less than age 8 and less than 80 pounds in weight must be restrained in a child restraint or booster seat. Children must be at least age 8 or at least 80 pounds in weight before being legally allowed to be buckled in by just a lap and shoulder belt. Children between 40 and 80 pounds may be restrained by a lap-ony safety belt if no lap and shoulder combination safety belts are available for use with a booster seat.

Refer to NC Occupant Restraint Laws for more information on legal requirements in North Carolina.