Seatbelts will prevent the head from hitting the windscreen, chest from hitting the steering wheel, and the pelvis from overriding the femur. A recent study has defined two types of frontal impacts; small overlap, where less than 30% of the vehicle front is involved in the crash, and large overlap where more than 30% is involved. Seatbelts were
more effective in preventing serious head injuries in large overlap compared to small overlap frontal impacts . In contrast, back impact leads to acceleration of the vehicle. This leads to hyperextension of the head (whiplash injury). This may lead to fractures of the posterior elements of the cervical spine including laminar, pedicle, and spinous process fractures. Seatbelts have a minor Cilengitide concentration role on preventing such injuries but the head support will reduce it [13, 17–20]. Side impact collision causes similar injuries as frontal impact. It also causes compression injuries to the pelvis which narrows its space. The head learn more and neck can be tilted laterally causing
nerve root avulsion and brachial plexus injury. Seatbelts have little effect on these injuries . In rollover collisions, the unbelted passenger may hit any part of the interior of the passenger compartment. More severe injuries are seen because of the hard shaking motions of the passenger inside the vehicle during the rollover. The occupant can also be ejected from the vehicle, which increases the severity of injury. Seatbelts can prevent the occupant from being ejected from the car . Unbelted occupants of RTC, become projectile within the vehicle which increases the risk of injury to other belted occupants. This
effect will reduce the benefit of seatbelts in prevention of injury in belted patients as they become fixed targets for the projectile unbelted patients. To maximize the benefit of seatbelts, drivers, front seat passengers and back seat passengers should be all belted [21, 22]. Seatbelt reduced perforating eye injuries by 60% . Rear seat occupants are much safer than front seat occupants . A study by Huelke and Compton  has shown that injury severity in restrained occupants was higher for front seat occupants compared with rear seat occupants. Rear seatbelt legislation was established in 1980s in USA, in 1986 Janus kinase (JAK) in Sweden, in 1989 in New Zealand, and in 1993 in the European Union . The relationship between velocity (V) and injury severity in belted occupants was studied, and showed a clear association between fatal injuries and high speed. This formula (Energy = 1/2 mass × V2), explains the relationship between the velocity of the vehicle and the amount of energy in RTC. Energy increases see more exponentially with increased velocity, so the more the velocity is the more serious and fatal the collision is. This relationship was also studied in a speed -injury curve. This curve shows clearly the strong relationship between high speed and severity of injury .