Which of these describes the correct way for an adult to wear a lap-and-shoulder belt?

Why B is correct

A restraint is engineered to load the skeleton rather than soft tissue, and the position is what decides which of those it gets. Across the hips, the lap portion is carried by the pelvis, which tolerates enormous force; across the abdomen it compresses organs and can ride inward under load in ways that cause internal injury. The shoulder strap belongs flat against the chest and collar bone, never tucked behind the back or under an arm, because the belt only works correctly as a system with both parts sharing the load. Slack matters as much as position — a loose belt permits you to travel further before it arrests you, and the forces rise sharply with that extra distance.

Why the other options are wrong

A. As loose as is comfortable so you can reach the controls easily

Comfort and protection pull in opposite directions here. Any slack you leave is distance travelled inside the cabin before the belt engages, and that extra travel converts into force absorbed by whatever part of you catches it.

C. Lap belt only, since the shoulder portion is optional in the back seat

Modern belts in every seating position are lap and shoulder together. Using only the lap portion lets the upper body fold forward over it, whichis how occupants strike the dashboard or the seat in front during a moderate crash.

D. Shoulder strap tucked under the arm and lap belt across the stomach

Moving the strap off the chest removes half the restraint from a frontal impact and puts the load onto ribs and soft tissue instead of bone. A strap sitting across the stomach does internal damage before it stops you doing anything else.

On the road

In a fifty mile per hour frontal collision, an unbelted or wrongly belted passenger keeps travelling at fifty until something stops them. The belt worn correctly stretches slightly over maybe a foot of travel, spreading that same stop across the strongest bones in the body.

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