What is the Function of a Seat Belt?

[SanMichael]

The function of a seat belt is to instantly tighten and secure the loose belt when a vehicle collision occurs or emergency braking is applied, preventing secondary collisions by firmly restraining the occupant in the seat. If the tightening force of the seat belt exceeds a certain limit, the force-limiting device will appropriately release the belt to maintain stable chest pressure. Methods for using seat belts: 1. The breaking load indicators for the belt, rope, and metal fittings; 2. The waist belt must be a single piece, with a width of 40 to 50mm and a length of 1300 to 1600mm; 3. The protective waist belt should be no less than 80mm in width and 600 to 700mm in length; 4. The safety rope diameter should be no less than 13mm.

[MacMicah]

Once when I was driving, I got rear-ended and my body jerked forward violently. The seatbelt instantly tightened and held me firmly in place. This thing mainly works through an internal retractor and an inertia locking mechanism—when the vehicle decelerates sharply, the webbing automatically locks. It not only prevents you from flying out and hitting the windshield but also disperses impact forces to avoid rib injuries. I later learned that seatbelts can reduce fatal risks by 45%, especially in side collisions where they work together with side airbags for dual protection. Remember, the three-point seatbelt is the correct way to use it—the diagonal strap should cross over the collarbone, not the neck. Now, whenever I sit in the back seat, I remind my family to buckle up. It’s way more effective than phone reminders.

[DiIvan]

Last time when I was driving my child to school, I had to brake suddenly. My four-year-old son remained firmly secured in the car seat thanks to the five-point harness. The pre-tensioning function of the seatbelt can respond to collision signals within 0.1 seconds, while the load limiter gradually releases energy to prevent injury from excessive tightening. A crash at 40 km/h in the city is equivalent to falling from the third floor, and the seatbelt is that lifesaving rope. It works best in conjunction with airbags because airbags deploy at speeds up to 300 km/h—without the seatbelt, you could actually be injured by the airbag. Remember, the webbing must not be twisted or knotted, as this can affect the locking function. I check the buckle monthly to ensure it operates smoothly.

[OJade]

Fatigue driving is the most dreaded hazard on highways, but once my steering wheel suddenly locked up, and the seatbelt's load limiter came to the rescue. This device acts like a smart spring, releasing a 38 cm buffer distance upon impact to prevent internal organ rupture. Studies show the fatality rate in accidents triples for those not wearing seatbelts, with rear passengers at the highest risk. I've seen numerous cases where minor collisions ejected unbelted occupants through windshields. Seatbelts work best when paired with headrests, preventing neck hyperextension during rear-end collisions. Regularly clean the webbing with soapy water—oil stains degrade fibers. Mechanics recommend replacing seatbelts every decade due to material fatigue.