Automotive Academy

When your child is sat in the car seat ideally you want the child to be coupled in as tightly as possible to the harness system and car seat, and the car seat as tight as possible to the vehicle with the seatbelt of latch system.

When you do this, the child gains all the benefit of “ride-down time” provided by the crushing frame of the vehicle in a crash.  With a loose installation of any kind, the child gets less ride down time and suffers a more severe crash into the harness system.  The analogy is that a tight installation is like catching an egg when you “give” backward with your hand to prevent it from breaking.

A loose installation will be more like holding your arm and hand rigid when you catch the egg.  The egg will splatter in your hand if you don’t give, much like what happens to the internal organs of a person when they are flung into a loose seatbelt or harness. Vehicle frames, advanced seatbelts and airbags are all designed to help passengers slow down more gradually.

Car seats themselves are not designed provide much ride-down time; their main functions are to prevent ejection and to allow the child to be coupled tightly to the vehicle so the frame can provide the necessary ride-down time.??

Rear-end crashes allow for a lot more ride-down time than frontal crashes, the potential energy in a rear-end crash is usually lower than a frontal crash because the speeds involved are slower. In addition, the two vehicles are not usually moving toward each other like they would be in a frontal crash.  That often means one vehicle is allowed to “give”, and the overall ride-down times for both vehicles are much greater, meaning lower forces on the passengers.