Most crashes and the most severe crashes happen at the front of a vehicle. In fact, 62% of crashes are frontal, and while 25% of crashes are from the side, nearly all of these have a frontal component.
“...relatively few passenger cars involved in fatal collisions are struck in rear locations (5%) compared with front (62%) and side (25%) impact locations.”2 -National Highway Traffic Safety Administartion. Traffic safety facts 1995. (DOT-Hs-808-471.) Washington, DC: US Department of Transportation, 1996.
When forward facing, children move forward during a crash, leaving the protective cocoon of the child safety seat. While the body is held in place by the harness system, the child’s limbs and disproportionately heavy head fly forward, causing strain on the neck.
“When in an FFCS [forward facing car seat], a frontal crash component causes the child’s head to move forward and further away from the car seat, limiting or removing any benefit of the side wings.”3 - B Henary, C P Sherwood, J R Crandall, R W Kent, F E Vaca, K B Arbogast, M J Bull Injury Prevention 2007;13:398-402. doi: 10.1136/ip.2006.015115 “Forward-facing infants and young children are particularly susceptible when compared with older children and adults to cervical spinal injuries because their relatively large head, lax cervical anatomy contributes to increased cervical spinal cord tension load during a frontal MVC [motor vehicle collision].”4 - Stalnaker RL. Spinal cord injuries to children in real world accidents. Child Occupant Protection 2nd Symposium. Warrendale, PA: Society of Automotive Engineers (SAE 933100), 1997:173-83.
During a frontal crash, a child’s body moves into the safety seat, which spreads the force over the entire body and absorbs the impact. This not only protects the child from flying debris or intrusions into the vehicle, but also prevents extreme strain on their delicate body.
“A rear-facing child seat reduces the risk of injury in a head-on collision by more than 80% when compared to a conventional forward-facing seat with harness system, as the force of an impact is distributed evenly over a large area.”5 - VTI — Swedish Road and Transport Research Institute (Rapport 489A, 2003) “In rear facing car seats, the head, neck, and spine are kept fully aligned, and the crash forces are distributed over all of these body areas.”6 - Elizabeth A Watson,1 Michael J Monteiro2 Cite this as: BMJ 2009;338:b1994 doi:10.1136/bmj.b1994 “...children are less likely to suffer severe crash injuries when sitting in a rear-facing seat than in a front-facing seat.” It is “estimated that children were around 75% less likely to suffer severe injuries in rear-facing seats.”7 - http://www.nhs.uk/news/2009/06June/Pages/CarSeatWarning.aspx citing research published in the British Medical Journal