The purpose of the anti-submergence protection system (ASPS) is to prevent the vehicle occupants from sliding forward when the vehicle brakes suddenly. But the most important function of ASPS is that when the vehicle is subjected to a frontal impact, with the use of a seat belt, the person is restricted to the seat without sliding forward, which can reduce the greater injury caused by the human body sliding forward. This system cooperates with seat belts and auxiliary airbags to achieve complementary effects. There are many particulars about anti-dive design. For example, the angle should not be too large, which will affect the ride comfort; the angle should not be too small; too small will not play the role of anti-diving.