Seat belts are the most important safety feature of every vehicle. They are designed to secure the driver and passengers of a vehicle against harmful movement that may result from a collision or a sudden stop.
Seat belts can reduce the risk of death or serious injury by about half, according to the Centers for Disease Control and Prevention.
But not all seat belts are the same. There are different types and features of seat belts that can offer different levels of protection and comfort. Here are some of the common seat belt features you may encounter in your car or when shopping for a new one:
Lap belt: This is the simplest and oldest type of seat belt. It consists of a single strap that goes across the lap of the occupant. It can prevent the occupant from being ejected from the vehicle, but it does not protect the upper body or the head from hitting the dashboard, steering wheel, or windshield. Lap belts are usually found in older cars or in the rear center seats of some cars.
Shoulder belt: This is a type of seat belt that goes across the chest and shoulder of the occupant. It can prevent the occupant from being ejected from the vehicle and reduce the impact to the upper body and head. However, it can also cause injuries to the neck, chest, or abdomen if it is not positioned correctly or if it is too tight or loose. Shoulder belts are usually combined with lap belts to form a three-point seat belt.
Three-point seat belt: This is the most common and effective type of seat belt. It consists of a lap belt and a shoulder belt that are connected at a single point near the hip. It can prevent the occupant from being ejected from the vehicle and distribute the crash forces over a larger area of the body, reducing the risk of injury. Three-point seat belts are mandatory for all front seats and most rear seats in modern cars.
• Pretensioner: This is a feature that tightens the seat belt when a crash is detected, removing any slack and holding the occupant firmly in place. It can reduce the movement of the occupant and prevent them from hitting hard surfaces or other occupants. Pretensioners are usually activated by sensors that measure the deceleration or impact of the vehicle.
• Load limiter: This is a feature that limits the amount of force that the seat belt applies to the occupant during a crash, preventing injuries caused by excessive pressure on the chest or abdomen. It can work by allowing some slack in the seat belt or by using a mechanism that absorbs some of the energy. Load limiters are usually combined with pretensioners to balance between restraining and cushioning the occupant.
• Adjustable upper anchor: This is a feature that allows the occupant to adjust the height of the shoulder belt to fit their size and position. It can improve the comfort and effectiveness of the seat belt by preventing it from rubbing against the neck or sliding off the shoulder. Adjustable upper anchors are usually found on the door pillar or on the seat itself.
• Buckle pretensioner: This is a feature that moves the buckle of the seat belt closer to the occupant when a crash is detected, reducing any slack in
the lap belt. It can prevent submarining, which is when an occupant slides under the lap belt and suffers injuries to their lower body or spine. Buckle pretensioners are usually activated by sensors that measure the deceleration or impact of the vehicle.
These are some of the features that can enhance the safety and comfort of seat belts in cars. However, no matter what type or feature of seat belt you have, the most important thing is to wear it properly and consistently every time you drive or ride in a car. Seat belts can save your life, but only if you use them correctly.