noun
seatbelt submarining
Technical term in automotive safety for when a passenger slides under the lap belt during a collision, often due to poor belt fit or reclined seating.
衝突時にサブマリン現象が起こると、腹部を強く圧迫されて重傷を負う危険がある。
If seatbelt submarining occurs during a collision, there is a risk of serious injury from strong abdominal compression.
From English 'submarine' + 現象 (phenomenon), describing the sliding-under motion resembling a submarine diving.